CN107689915A - Message forwarding method and device - Google Patents

Abstract

The invention provides a kind of message forwarding method and device, wherein, this method includes：First node receives message to be forwarded, wherein, the destination address of the message is section point；First node searches target topology corresponding with the message in the topology previously generated, wherein, the topology previously generated includes：First the second topology of topological sum for generating to obtain according to maximum redundancy tree MRT algorithms, the 3rd topology obtained according to SPF SPF algorithms, the above-mentioned topology of first topological sum second and the 3rd topology are different each other；Above-mentioned first node is searched in target topology for being forwarded to the next-hop node of above-mentioned section point, and forwards the packet to next-hop node.By the present invention, the purpose that Segment routing network is combined with MTR functions is realized.

Description

Message forwarding method and device

Technical field

The present invention relates to the communications field, in particular to a kind of message forwarding method and device.

Background technology

Quick heavy-route (the Fast Re- of maximum redundancy tree (Maximally Redundant Trees, referred to as MRT) Route, referred to as FRR) it is a kind of newer FRR technologies, it is right using two different forwarding topologys to greatest extent in the technology The link or node failure of single-point can provide 100% protection.MRT frameworks define two kinds of forwarding mechanisms, i.e. label distribution is assisted Discuss (Label Distribution Protocol, referred to as LDP) forwarding mechanism and procotol-tunnel (IP-tunnel) turns Hair mechanism.LDP forwarding mechanisms forward behavior by different labels to distinguish the topological forwarding behavior of acquiescence or MRT so that Forwarding plane, which does not make any upgrading, can support MRT-FRR.IP-tunnel forwarding mechanisms then need to waste special MRT Loopback addresses are supported to forward, and equally also cause Forwarding plane not make any upgrading and can support MRT-FRR.Compare and Speech, LDP forwarding mechanisms are more reasonable, so the acquiescence maximum redundancy tree configuration file default MRT Profile of MRT frameworks Middle use is exactly LDP forwarding mechanisms, not yet defines other MRT Profiles at present.

Segment routing technology will allow node be that message specifies its forward-path, it is rather than most short by general Path forwards, by adding in messages by the letter of the segment identification Segment ID section list Segment List correlations formed Breath, it is not necessary to be on the intermediate node status information of the maintenance per path.Segment routing primary expansion IGP is to support to notice and learn Practise Segment ID.Typically in the network of Segment routing is deployed, in this way it is no longer necessary to dispose LDP and be based on Traffic Engineering extensions RSVP (Resource ReSerVation Protocol-Traffic Extension, referred to as RSVP-TE) .In Segment routing network, it is known that FRR technologies have the unrelated loop free alternative paths (Topology of topology Independent Loop Free Alternate, referred to as TI-LFA), but the safeguard rule that TI-LFA is defined is very multiple It is miscellaneous and also immature.

MRT functions are introduced in Segment routing network to have important meaning, and still, there has been no documents so far The content of this respect, therefore, in the related art, it can not realize that Segment routing network is combined with MTR functions.

The content of the invention

The embodiments of the invention provide a kind of message forwarding method and device, at least to solve nothing present in correlation technique Method realizes the problem of Segment routing network is combined with MTR functions.

According to one embodiment of present invention, there is provided a kind of message forwarding method, including：First node receives to be forwarded Message, wherein, the destination address of the message is section point；The first node searched in the topology previously generated with Target topology corresponding to the message, wherein, the topology previously generated includes：Generated according to maximum redundancy tree MRT algorithms First obtained the second topology of topological sum, the 3rd topology obtained according to SPF SPF algorithms, first topological sum Described second topological and described 3rd topology is different each other；The first node is searched in the target topology to be used for The next-hop node of the section point is forwarded to, and the message is forwarded to by the next-hop section based on predetermined forwarding mechanism Point, wherein, the predetermined forwarding mechanism uses point based on tunnel nested mode of every topology per Segment routing overall situation block SRGB Section routing forwarding mechanism.

Alternatively, methods described also includes：The first node according to the MRT algorithms from first topology to institute State routeing and being determined in second topology into the route of the destination address for protecting the described 3rd to open up for destination address The protection of route in flutterring to the destination address is route, and determines topology corresponding to the protection route to protect topology；With/ Or, the first node according to color-coded information from first topology to termination point of a tunnel route and it is described second topology In determined into the route of termination point of a tunnel for protect in the 3rd topology to the destination address route protection route, And determine that topology corresponding to the protection route is protection topology, wherein, the termination point of a tunnel is that the first node is protection Destination address and the distant-end node selected, the distant-end node are no loop loop-free for trouble point, work as failure The first node is used to the MRT tunnel encapsulation messages of the distant-end node during generation.

Alternatively, the first node searches target topology bag corresponding with the message in the topology previously generated Include：The first node judges whether the link for being used to reach the section point in the 3rd topology breaks down； Judge in the case of not breaking down, the first node determines the 3rd topology for target topology；And/or In the case where judging failure, the first node determines the protection topology for target topology.

Alternatively, before the message to be forwarded is received, methods described also includes the first node：Described first Node generates to obtain the topology of the first topological sum second according to the MRT algorithms, and generates to obtain according to the SPF algorithms 3rd topology.

Alternatively, the first node generates to obtain the topology of the first topological sum second according to the MRT algorithms, and Generating to obtain the 3rd topology according to the SPF algorithms includes：The first node determines the MRT where the first node Island, wherein, the MRT Island are by being in same domain in the first node and with the first node Open Shortest Path First on area or same levels level other nodes OSPF or Intermediate System-to-Intermediate System Under ISIS examples after enabled Segment routing SR and maximum redundancy tree configuration file MRT profile where the first node Area or level in by the first node and other described nodes reciprocally negotiate what is formed；The first node is based on institute State MRT Island and run the MRT algorithms and generate the second topology described in first topological sum, and, based on the area or Level runs the SPF algorithms generation the 3rd topology.

Alternatively, specified in the MRT profile and use the predetermined forwarding mechanism.

Alternatively, methods described also includes at least one of：The first node is that the described first topology distributes first Segment routing overall situation block SRGB, and by the first SRGB in the domain area or level level where the MRT Island Flood；The first node is that the described second topology distributes the second Segment routing overall situation block SRGB, and the 2nd SRGB is existed Flooded in domain area or level level where the MRT Island；The first node is the described 3rd topology distribution the Three Segment routing overall situation block SRGB, and by the 3rd SRGB in all the domain area or level where the first node Flooded in level；The first node receives the topological Segment routing overall situation block previously generated on other nodes SRGB, records the topological SRGB previously generated on other described nodes and will be described pre- on other described nodes The topological SRGB first generated continues to be advertised to the node in addition to other described nodes.

Alternatively, the message is forwarded to the next-hop node and included by the first node：The first node is true The outgoing label of the fixed first node matched with the message；The first node encapsulates the outgoing label of the first node The next-hop node is sent to onto the message, and by the message after encapsulation.

Alternatively, the outgoing label for the first node that the first node determines to match with the message includes：Work as institute State target topology for the described 3rd it is topological when, the outgoing label of the correspondence of the first node target topology is by the first segment Prefix index prefix-sid of the point based on purpose prefix prefix corresponding to destination address is corresponding with the next-hop node What the SRGB of the 3rd topology was calculated.

Alternatively, the outgoing label for the first node that the first node determines to match with the message includes：Work as institute State target topology for described first it is topological or it is described second it is topological when：If the section point is the section in the MRT Island It is described when purpose prefix prefix is the node level prefix prefix of the section point corresponding to point and the destination address First node is determined as follows the outgoing label of the correspondence target topology of the first node：The first node Before the outgoing label of the corresponding target topology is by node level prefix prefix of the first node based on the section point The SRGB for sewing the index prefix-sid target topologys corresponding with the next-hop node is calculated；If second section Point is not second section for purpose prefix prefix corresponding to the node in the MRT Island or the destination address During the not a node level prefix prefix of point, the first node judges whether the next-hop node is outside the MRT Island Node；When judged result is no, the first node is determined as follows the correspondence mesh of the first node Mark the outgoing label of topology：The outgoing label of the correspondence target topology of the first node is label stack, and outer layer label is described For first node to the label of termination point of a tunnel, vpn label is label of the termination point of a tunnel to the purpose prefix prefix；Its In, the outer layer label by node level prefix prefix of the first node based on the termination point of a tunnel prefix index Prefix-sid and the SRGB of the extremely target topology of the next-hop node of the termination point of a tunnel in target topology are calculated Obtain, the vpn label is by prefix index prefix-sid of the first node based on the purpose prefix prefix and institute The SRGB for stating the 3rd topology of termination point of a tunnel is calculated；In judged result for when being, the first node is in the following way Determine the outgoing label of the correspondence target topology of the first node：The correspondence target topology of the first node goes out Label is by prefix index prefix-sid of the first node based on the purpose prefix prefix and the next-hop node The SRGB of correspondence the 3rd topology be calculated.

Alternatively, the first node by the outgoing label of the first node be encapsulated on the message include it is following at least One of：When the type of message of the message is Internet protocol IP message, on the IP heads of the IP messages described the in pressure The outgoing label of one node；When the type of message of the message is Segment routing SR label packets, by the SR label packets Outgoing label of the stack top tag replacement of label stack into the first node.

Alternatively, the first node determines that the outgoing label of the first node includes：When the first node and described When section point is same node, then the first node is described based on the next-hop node that target topology determines First node, the first node do not have outgoing label.

Alternatively, methods described also includes：When the first node and the section point are same node, including： When the type of message of the message is Internet protocol IP message, the first node is by the message up sending to described first The control plane of node；And/or when the type of message of the message is Segment routing SR label packets, the first node The stack top label of the label stack of the SR label packets is ejected, and continue the label stack based on the message lower floor's label or IP heads are tabled look-up forwarding.

According to another embodiment of the invention, a kind of apparatus for forwarding message is additionally provided, including：Receiving module, it is used for Message to be forwarded is received, wherein, the destination address of the message is section point；Searching modul, for previously generating Target topology corresponding with the message is searched in topology, wherein, the topology previously generated includes：According to maximum redundancy tree MRT algorithms generate first obtained the second topology of topological sum, the 3rd topology obtained according to SPF SPF algorithms, institute It is different each other to state the second topological and described 3rd topology described in the first topological sum；Forwarding module, in the target The next-hop node for being forwarded to the section point is searched in topology, and is forwarded the message based on predetermined forwarding mechanism To the next-hop node, wherein, the predetermined forwarding mechanism is used based on tunnel of every topology per Segment routing overall situation block SRGB The Segment routing forwarding mechanism of road nested mode.

According to still another embodiment of the invention, a kind of storage medium is additionally provided.The storage medium is arranged to storage and used In the program code for performing above-mentioned steps.

By the present invention, MRT functions are introduced in Segment routing network, it is achieved thereby that Segment routing network and MTR work( The purpose that can be combined.

Brief description of the drawings

Accompanying drawing described herein is used for providing a further understanding of the present invention, forms the part of the application, this hair Bright schematic description and description is used to explain the present invention, does not form inappropriate limitation of the present invention.In the accompanying drawings：

Fig. 1 is the flow chart of message forwarding method according to embodiments of the present invention；

Fig. 2 is the MRT Profile schematic diagrames according to the specific embodiment of the invention；

Fig. 3 is the format chart according to the ISIS MT SR-Capabilities Sub-TLV of the specific embodiment of the invention；

Fig. 4 is the format chart according to the OSPF MT SID/Label Range TLV of the specific embodiment of the invention；

Fig. 5 is the network topological diagram according to the specific embodiment of the invention one；

Fig. 6 is the network topological diagram according to the specific embodiment of the invention two；

Fig. 7 is the network topological diagram according to the specific embodiment of the invention three；

Fig. 8 is the structured flowchart of apparatus for forwarding message according to embodiments of the present invention.

Embodiment

Describe the present invention in detail below with reference to accompanying drawing and in conjunction with the embodiments.It should be noted that do not conflicting In the case of, the feature in embodiment and embodiment in the application can be mutually combined.

It should be noted that term " first " in description and claims of this specification and above-mentioned accompanying drawing, " Two " etc. be for distinguishing similar object, without for describing specific order or precedence.

A kind of message forwarding method is provided in the present embodiment, and Fig. 1 is message forwarding side according to embodiments of the present invention The flow chart of method, as shown in figure 1, the flow comprises the following steps：

Step S102, first node receive message to be forwarded, wherein, the destination address of the message is section point；

Step S104, first node search target topology corresponding with the message in the topology previously generated, wherein, The topology previously generated includes：First the second topology of topological sum for generating to obtain according to maximum redundancy tree MRT algorithms, according to most The 3rd topology that preferential (Shortest Path First, the referred to as SPF) algorithm of short path obtains, above-mentioned first topological sum the Two topologys and the 3rd topology are different each other；

Step S106, above-mentioned first node search the next-hop section for being forwarded to above-mentioned section point in target topology Point, and forward the packet to next-hop node.

Wherein, above-mentioned first node can be any node in MRT Island, and above-mentioned section point can be SR Any node in Domain, the section point are likely to be in the MRT Island or outside MRT Island.Above-mentioned One the second topology of topological sum can be MRT-red topologys with one, and one is MRT-blue topologys；The 3rd above-mentioned topology can be MT-default topologys.

In the above-described embodiments, first node can be based on predetermined repeater-transmitter when forwarding the packet to next-hop node System is forwarded, and the predetermined forwarding mechanism is based on segmentation of every topology per Segment routing overall situation block SRGB tunnel nested mode Routing forwarding mechanism.

By above-mentioned steps, MRT functions are introduced in Segment routing network, it is achieved thereby that Segment routing network and MTR The purpose that function combines.

In an optional embodiment, the above method also includes：First node according to MRT algorithms from the first topology to Determine to be used to protect in above-mentioned 3rd topology extremely into the route of destination address in the route of the destination address and the second topology The protection route of the route of destination address, and determine topology corresponding to protection route for protection topology；And/or first node According to color-coded information from the first topology to termination point of a tunnel route and the second topology in into the route of termination point of a tunnel really The fixed protection for being used to protect the route in the 3rd topology to destination address is route, and determines topology corresponding to protection route to protect Shield topology, wherein, the distant-end node that the termination point of a tunnel is first node to be selected for protection destination address, the distant-end node It is no loop loop-free for trouble point, the first node is used to the MRT tunnels of the distant-end node when an error occurs Road encapsulated message.In the present embodiment, when it is determined that protecting topological, it may be determined that the first topology is protection topology, can also be true Fixed second topology is protection topology, and which specifically chosen topology needs to be determined according to actual conditions as protection topology.

In an optional embodiment, above-mentioned first node is searched corresponding with above-mentioned message in the topology previously generated Target topology include：First node judges whether the link for being used to reach section point in above-mentioned 3rd topology event occurs Barrier；In the case where judging not break down, above-mentioned first node determines the 3rd topology for above-mentioned target topology；And/or In the case where judging failure, first node determines above-mentioned protection topology for target topology.In the present embodiment, chain is worked as When road does not have failure, it can continue to carry out message forwarding according to the topology of acquiescence, it is necessary to use protection after link breaks down Topology carries out message forwarding.

In an optional embodiment, above-mentioned first node is before the message to be forwarded is received, the above method Also include：First node generates to obtain first the second topology of topological sum according to MRT algorithms, and generates to obtain according to SPF algorithms 3rd topology.

In an optional embodiment, above-mentioned first node is generated to obtain the first topological sum second and opened up according to MRT algorithms Flutter, and generate to obtain the 3rd topology according to SPF algorithms and include：First node determines the MRT where first node Island, wherein, the MRT Island are by being in same domain area or same layer in first node and with first node Open Shortest Path First on secondary level other nodes (Open shortest Path First, referred to as OSPF) or Person's Intermediate System-to-Intermediate System (Intermediate system to Intermediate system, referred to as ISIS) is real Under example after enabled Segment routing SR and maximum redundancy tree configuration file MRT profile in the area where first node or Reciprocally negotiate what is formed by first node and other nodes in level；The first node is based on above-mentioned MRT Island operations MRT Algorithm generation the second topology of the first topological sum, and, based on the topology of above-mentioned area or level operation SPF algorithms generation the 3rd.

Specified in an optional embodiment, in above-mentioned MRT profile and use predetermined forwarding mechanism, i.e. in use The Segment routing forwarding mechanism for the tunnel nested mode based on the every Segment routing overall situation block SRGB of every topology stated.

In an optional embodiment, the above method also includes at least one of：First node is the first topology point With the first Segment routing overall situation block SRGB, and by the first SRGB in the domain area or level level where MRT Island it is general Flood；First node is that the second topology distributes the second Segment routing overall situation block SRGB, and by the 2nd SRGB where MRT Island Domain area or level level in flood；First node is that the 3rd topology distributes the 3rd Segment routing overall situation block SRGB, and by the Three SRGB flood in all the domain area or level level where first node；First node receives pre- on other nodes The topological Segment routing overall situation block SRGB first generated, record the topological SRGB previously generated on other nodes and incite somebody to action The topological SRGB previously generated on other nodes continues to be advertised to the node in addition to other nodes.In the present embodiment In, each node can be first topological, second topological, the 3rd topological one SRGB of generation respectively, for different topology lifes Into SRGB be that the SRGB of different and different nodes generations is independent.

In an optional embodiment, above-mentioned first node, which forwards the packet to next-hop node, to be included：First node It is determined that the outgoing label of the first node matched with above-mentioned message；The outgoing label of above-mentioned first node is encapsulated into message by first node On, and the message after encapsulation is sent to next-hop node.In the present embodiment, for different types of message, the envelope of label Dress mode is different.

In an optional embodiment, above-mentioned first node determines the outgoing label bag of the first node matched with message Include：When above-mentioned target topology is topological for the 3rd, the outgoing label of the corresponding target topology of first node is based on mesh by first node Address corresponding to purpose prefix prefix prefix index prefix-sid it is corresponding with next-hop node the 3rd topology What SRGB was calculated.

In an optional embodiment, above-mentioned first node determines the outgoing label bag of the first node matched with message Include：When above-mentioned target topology is the first topology or second is topological：If above-mentioned section point be MRT Island in node simultaneously And purpose prefix prefix corresponding to destination address be section point node level prefix prefix when, first node passes through as follows Mode determines the outgoing label of the corresponding target topology of first node：The outgoing label of the corresponding target topology of first node is by first segment Node level prefix prefix prefix index prefix-sid of the point based on section point opens up with the corresponding target of next-hop node The SRGB flutterred is calculated；If section point is not purpose prefix corresponding to the node or destination address in MRT Island When prefix is the not a node level prefix prefix of section point, first node judges whether next-hop node is MRT Island Outer node；When judged result is no, first node is determined as follows going out for the corresponding target topology of first node Label：The outgoing label of the corresponding target topology of first node is label stack, and outer layer label is mark of the first node to termination point of a tunnel Label, vpn label are label of the termination point of a tunnel to purpose prefix prefix；Wherein, outer layer label is based on tunnel end by first node The node level prefix prefix of point prefix index prefix-sid and the interior next-hop node to termination point of a tunnel of target topology The SRGB of target topology is calculated, and vpn label is by prefix index prefix- of the first node based on purpose prefix prefix The SRGB of 3rd topology of sid and termination point of a tunnel is calculated；In judged result for when being, first node is true in the following way Determine the outgoing label of the corresponding target topology of first node：The outgoing label of the corresponding target topology of first node is based on by first node What the SRGB of purpose prefix prefix prefix index prefix-sid the 3rd topologys corresponding with next-hop node was calculated.

In an optional embodiment, the outgoing label of first node is encapsulated on above-mentioned message and wrapped by above-mentioned first node Include at least one of：When the type of message of above-mentioned message is Internet protocol IP message, on the IP heads of IP messages in pressure The outgoing label of above-mentioned first node；When the type of message of message is Segment routing SR label packets, by above-mentioned SR label packets Label stack stack top tag replacement into first node outgoing label.

In an optional embodiment, above-mentioned first node determines that the outgoing label of first node includes：Work as first node When with the section point being same node, then first node is first node based on the next-hop node that target topology determines, The first node does not have outgoing label.That is, if above-mentioned first node is exactly section point, first node is based on target topology really Fixed next-hop node is exactly itself, now without outgoing label.

In an optional embodiment, the above method also includes：When first node and section point are same node, Including：When the type of message of message is Internet protocol IP message, the first node is by above-mentioned message up sending to first node Control plane；And/or when the type of message of above-mentioned message is Segment routing SR label packets, the first node marks SR The stack top label ejection of the label stack of message is signed, and continues lower floor's label of the label stack based on above-mentioned message or IP heads are tabled look-up and turned Hair.

With reference to specific embodiment, the present invention will be described：

In embodiments of the present invention, Segment routing is combined with MRT technologies, there is provided one kind is based on Segment routing repeater-transmitter The MRT-FRR methods of system.In the present embodiment, a kind of MRT Profile are increased newly for MRT frameworks, uses Segment routing repeater-transmitter System, the topological forwarding behavior of acquiescence and MRT topology forwarding behaviors are distinguished by Segment routing forwarding mechanism.

The MRT-FRR methods based on Segment routing forwarding mechanism in the embodiment of the present invention comprise the following steps：

The first step, new MRT configuration file MRT Profile are defined, with giving tacit consent to MRT configuration file default MRT Profile is compared, and difference is mainly reflected in new MRT Profile and uses MRT SR-LSP based on multi-SRGB Tunneling forwarding mechanisms.Wherein, SR-LSP refers to the Segment routing (Segment based on prefix-sid generations Routing, referred to as SR) type LSP, be similar with LDP LSP.SR-LSP tunneling forwarding mechanisms refer to MRT SR LSP in topology are established by purpose node of MRT egress nodes, that is, after MRT FRR switchings occur, in MRT On Ingress nodes, the SR LSP in acquiescence topology are that tunnel is nested in the SR LSP of MRT topologys.SR-LSP During tunneling forwarding mechanisms, it is the silent of purpose prefix distribution that MRT Ingress nodes, which need to perceive MRT Egress nodes, Recognize topologically corresponding SR labels.Multi-SRGB refers to every topology per SRGB, i.e. acquiescence topology and MRT-red topologys and MRT- SRGB in blue topologys is different.

Second step, enabled in IGP area/level on each node (can be only part of nodes) under corresponding IGP examples MRT and above-mentioned new MRT Profile are supported, corresponding MRT Island are generated for above-mentioned new MRT Profile.Base Corresponding MRT-red topologys and MRT-blue topologys, corresponding MT-ID difference are generated in MRT Island operation MRT algorithms It is designated as MT-red and MT-blue.The topologically corresponding MT-ID of the acquiescence generated based on SPF algorithms can be designated as MT- in addition default。

3rd step, the IGP examples on each node of Segment routing are enabled, if also enabling MRT and supporting New MRT Profile are stated, then is not only MT-default distribution MT-default SRGB, also distributes MT-red for MT-red SRGB, and distribute MT-blue SRGB for MT-blue.Here only (MT-default, prefix) distribution phase can be taken The prefix-sid that answers simultaneously floods with (MT-default, prefix), is no longer respectively (MT-red, prefix) and (MT- Blue, prefix) the corresponding prefix-sid of distribution and general with (MT-red, prefix) and (MT-blue, prefix) respectively Flood.

Explanation：Redundancy floods, and (MT-red, prefix) and (MT-blue, prefix) prefix-sid will influence accordingly Network performance, and because being the related information of MRT can only also be flooded in the area where MRT Island, if should Prefix is the prefix outside area, then the prefix is that will not perceive MT-red and MT-blue on original advertisement node Topology, then also do not know where to begin and (MT-red, prefix) and (MT-blue, prefix) phase is distributed on original advertisement node The prefix-sid that answers simultaneously floods to MRT-Island.Node in MRT Island.On the contrary can otherwise such as SRMS comes agent allocation (MT-red, prefix) and (MT-blue, prefix) corresponding prefix-sid, but this method Do not possess actual operability.

4th step, source node S in MRT Island for other destination node D in Island node level prefix (being designated as D-loopback0) calculates the main next-hops of SPF and MRT-blue/MRT-red next-hops, i.e. (MT-default, D- Loopback0 the main next-hops of SPF will be included in), MRT-blue next-hops will be included in (MT-blue, D-loopback0), MRT-red next-hops will be included in (MT-red, D-loopback0).And determine it is above-mentioned MRT- on earth by MRT algorithms Blue next-hops or MRT-red next-hops protect the above-mentioned main next-hops of SPF.

MT-default SR outgoing label in the above-mentioned main next-hops of SPF is based on (MT-default, D-loopback0) phase The prefix-sid answered calculations of offset in the MT-default SRGB of next-hop node obtains；Above-mentioned MRT-blue next-hops In MRT-blue SR outgoing label be based on (MT-default, D-loopback0) corresponding prefix-sid under MRT-blue Calculations of offset obtains in the MT-blue SRGB of one hop node；MRT-red SR outgoing label bases in above-mentioned MRT-red next-hops In (MT-default, D-loopback0) corresponding prefix-sid in the MT-red SRGB of MRT-red next-hop nodes Calculations of offset obtains.

Corresponding forwarding equivalence class will be generated to next-hop label forwarding list according to (MT-default, D-loopback0) First (Forwarding Equivalence Class to NHLFE, referred to as FTN) list item, main NHLFE include above-mentioned SPF master Next-hop and corresponding MT-default SR outgoing label, MRT-FRR include above-mentioned choose for protecting SPF master next for NHLFE The MRT-red next-hops or MRT-blue next-hops of jump and corresponding MRT-red SR outgoing label or MRT-blue SR outgoing label. Corresponding ILM list items are also generated according to (MT-default, D-loopback0), its MT-default SR enters label and is based on (MT- Default, D-loopback0) the MT-default SRGB of corresponding prefix-sid and S nodes calculate, NHLFE with it is upper It is identical to state FTN list items.

S nodes also enter label mapping (Incoming Label accordingly for (MT-blue, D-loopback0) generation in addition Map, referred to as ILM) list item, it is corresponding based on (MT-default, D-loopback0) that its MT-blue SR enters label The MT-blue SRGB of prefix-sid and S nodes are calculated, and NHLFE includes MRT-blue next-hops and corresponding MT-blue SR outgoing label.Also corresponding ILM list items are generated for (MT-red, D-loopback0), its MT-red SR enters label and is based on (MT- Default, D-loopback0) the MT-red SRGB of corresponding prefix-sid and S nodes calculate, and NHLFE includes MRT- Red next-hops and corresponding MT-red SR outgoing label.

5th step, the source node S in MRT Island is also to be other in MRT Island or outside MRT Island Prefix (all other prefix in the network i.e. in addition to the node level prefix residing for S in MRT Island) is calculated The main next-hops of SPF and MRT-FRR backup next-hops, MRT-FRR backup next skip lists are shown as corresponding MRT Egress nodes (being designated as E, corresponding node level prefix is designated as E-loopback0) and color-coded information alert are selected to E nodes The main next-hops of above-mentioned SPF are protected in MRT-red paths or MRT-blue paths.

It is corresponding that MT-default SR outgoing label in the above-mentioned main next-hops of SPF is based on (MT-default, prefix) Prefix-sid calculations of offset in the MT-default SRGB of next-hop node obtains；Above-mentioned MRT-FRR backups next-hop will Corresponding one enters label stack：Bottom label is the MT-default SR labels that E nodes are purpose prefix distribution, that is, is based on (MT-default, prefix) corresponding prefix-sid calculations of offset in the MT-default SRGB of E nodes obtains；On (it is MRT-blue or MRT- to choose bottom according to color-coded information in MRT-blue the or MRT-red paths that layer label is S to E Red paths) corresponding to SR enter label, i.e., based on (MT-default, E-loopback0) corresponding prefix-sid in S nodes MT-blue SRGB or MT-red SRGB in calculations of offset obtain.For needing top layer SR entering label lookup before actual forward Corresponding ILM list items change outgoing label and direct-connected next-hop into, i.e., by it is above-mentioned enter label stack be converted into outgoing label stack.

Corresponding FTN list items will be generated according to (MT-default, prefix), main NHLFE includes the main next-hops of above-mentioned SPF And corresponding MT-default SR outgoing label, standby NHLFE, which is included, is based on above-mentioned MRT Egress nodes E and its respective color mark What will information was calculated enters label stack (needing to change outgoing label stack into before being used for actual forward).According to (MT-default, Prefix corresponding ILM list items) are also generated, its MT-default SR enters label and is based on (MT-default, prefix) accordingly Prefix-sid calculations of offset in the MT-default SRGB of S nodes obtains, and NHLFE is identical with above-mentioned FTN list items.If Prefix is that S nodes are local or direct-connected prefix, then does not have NHLFE information.

Cross-domain forwarding behavior needs especially to consider：

Described according to MRT frameworks, for OSPF, flow of the destination address in area is along MRT-red or MRT- , it is necessary to stay in MRT-Red or MRT-Blue topologys when blue paths forward.But for leaving area flow, it would be desirable that It leaves MRT-Red or MRT-Blue topologys, comes back to the acquiescence topology of shortest path forwarding.ISIS is similar.

If S is as ABR nodes, for those and the IGP neighbours to purpose prefix in same area, ABR will Notice following prefix-sid：

prefix-sid for(MT-default,prefix)

And for those with to purpose prefix, the IGP neighbours in same area, ABR will not notice following prefix- sid：

prefix-sid for(MT-default,prefix)with flag Rainbow

This measure will cause ABR to be received from an area for supporting option different from option described in the embodiment of the present invention Message in avoid the occurrence of MRT SR label, message otherwise can be caused to enter MRT paths.

6th step, when failure occurs, IP or SR label unicast traffics can be forwarded along MRT paths as follows：

MRT Ingress nodes are based on (MT-default, prefix) corresponding FTN list items and instruct IP messages, or ILM tables Item instructs SR label packets to forward.It is specifically divided into two kinds of situations：If 1) flow matches be in MRT Island some section FTN or ILM list items corresponding to point level (MT-default, prefix), then can be by the top-level tab MT- of SR label packets Default SR enter Tag switching into being sent to MRT-red or MRT-blue next-hops after MR-red or MRT-blue SR outgoing label； Or it can will be sent to MRT-red or MRT-blue next-hops after the upper MRT-red or MRT-blue SR outgoing label of IP messages directly pressure. 2) if flow matches is FTN or ILM list items corresponding to other (MT-default, prefix), then can be by SR label packets Top-level tab MT-default SR enter Tag switching into MRT Egress nodes be the prefix distribution MT-default SR labels, it is sent to MRT Egress and saves after compressing to MR-red the or MRT-blue SR outgoing label of MRT Egress nodes MRT-red the or MRT-blue next-hops of point；Or IP messages can directly be pressed the up to MR-red of MRT Egress nodes or It is sent to after MRT-blue SR outgoing label to MRT-red the or MRT-blue next-hops of MRT Egress nodes.

MRT Transit nodes based on the node level (MT-red, prefix) to MRT Egress or (MT-blue, Prefix) corresponding SR ILM list items instruct message to forward, continue by MRT-red or MRT-blue SR enter Tag switching into MRT-red or MRT-blue next-hops are sent to after MRT-red or MRT-blue SR outgoing label.

MRT Egress node bullets fall enter label to MRT-red the or MRT-blue SR of its own after, based on lower floor (MT- Default, prefix) corresponding to the corresponding ILM list items of MT-default SR label lookups instruct message to forward, or IP report Literary head is directly based upon purpose IP forwardings after exposing.

The implementation to technical scheme is described in further detail below in conjunction with the accompanying drawings：

In present embodiment, the MRT Profile in the embodiment of the present invention are illustrated first：

Fig. 2 is the MRT Profile schematic diagrames according to the specific embodiment of the invention, MRT as shown in Figure 2 Profile, it is essentially identical with the default MRT Profile defined in RFC7812, and difference is MRT Forwarding Mechanism options are SR-LSP based on multi-SRGB tunneling Option.

Fig. 3 be according to the ISIS MT SR-Capabilities Sub-TLV of specific embodiment of the invention format chart, ISIS MT SR-Capabilities Sub-TLV forms as shown in Figure 3, with draft-ietf-isis-segment- The SR-Capabilities Sub-TLV provided in routing-extensions are essentially identical, and difference has been more MT-ID words Section, to support to notice different SRGB for different topologys.

Fig. 4 is according to the OSPF MT SID/Label Range TLV of specific embodiment of the invention format chart, is such as schemed OSPF MT SID/Label Range TLV forms shown in 4, with draft-ietf-ospf-segment-routing- The SID/Label Range TLV provided in extensions are essentially identical, and difference has been more MT-ID fields, to support to be directed to Different topologys notices different SRGB.

Specific embodiment one

The MRT paths forwarding process that description purpose prefix is in MRT Island by the present embodiment, Fig. 5 are according to this The network topological diagram of invention specific embodiment one, as shown in figure 5, running OSPF in network, all nodes are in same area It is interior, the MRT defined in Segment routing function and the enabled embodiment of the present invention is enabled under corresponding OSPF examples Profile.S is established to destination node D prefix MRT paths as source node, is then based on this MRT trail protection SPF Main path.Comprise the following steps：

MRT defined in SR and the embodiment of the present invention is enabled under OSPF examples on each nodes of step S501, S, A, B, D Profile, then they a MRT Island is formed in area.And use MRT SR- due to being specified in MRT Profile LSP based on multi-SRGB tunneling Option are as forwarding mechanism, then each node is except distributing MT- Beyond default SRGB, also additional allocation MT-red SRGB and MT-blue SRGB, such as on S nodes can by this three Kind SRGB is designated as respectively：MT_default_SRGB_S [], MT_red_SRGB_S [], MT_blue_SRGB_S [].Other nodes It is similar.

The MT-default topologys that will be obtained in MRT Island on each node based on SPF algorithms in area, and be based on MRT algorithms obtain MT-red and MT-blue topologys.For example be S-D to destination node D MT-default paths on S nodes, MT-red paths are also S-D, and MT-blue paths are S-A-B-D.

The corresponding prefix list items of Topology g eneration are based on each node, such as on S nodes, to mesh in MT-default topologys Node D node level prefix D-loopback0 MT-default next-hops be D, and choose in MT-blue topologys Protect MT-default next-hops D in the MT-blue paths provided, then corresponding MRT-FRR next-hops will be copied to be above-mentioned Next-hop in MT-blue is A, referred to as MRT-blue next-hops.Assuming that (MT-default, D-loopback0) node- Sid is SID0_D, then outgoing label corresponding to above-mentioned MT-default next-hops D is MT_default_SRGB_D [SID0_D], on It is MT_blue_SRGB_A [SID0_D] to state outgoing label corresponding to MRT-blue next-hops A.Below to the list item on part of nodes It is illustrated：

S nodes：

FTN for(MT-default,D-loopback0)

Main NHLFE：Next-hop is D, and outgoing label is MT_default_SRGB_D [SID0_D]

Standby NHLFE：Next-hop is A, and outgoing label is MT_default_SRGB_A [SID0_D]

ILM for(MT-default,D-loopback0)

It is MT_default_SRGB_S [SID0_D] to enter label

Main NHLFE：Next-hop is D, and outgoing label is MT_default_SRGB_D [SID0_D]

Standby NHLFE：Next-hop is A, and outgoing label is MT_default_SRGB_A [SID0_D]

A nodes：

ILM for(MT-blue,D-loopback0)

It is MT_blue_SRGB_A [SID0_D] to enter label

NHLFE：Next-hop is B, and outgoing label is MT_blue_SRGB_B [SID0_D]

B node：

ILM for(MT-blue,D-loopback0)

It is MT_blue_SRGB_B [SID0_D] to enter label

NHLFE：Next-hop is D, and outgoing label is MT_blue_SRGB_D [SID0_D]

D nodes：

ILM for(MT-blue,D-loopback0)

It is MT_blue_SRGB_D [SID0_D] to enter label

NHLFE：Nothing.Represent that SR-LSP has terminated.

Step S502, the message for being sent to destination D-loopback0, when link S-D breaks down, S nodes will As MRT ingress nodes by flow switch to preprepared MRT-blue next-hop A, that is, start message along MT- Blue paths S-A-B-D is forwarded.

If what S was received is MT-default SR label packets, it is based on ILM for (MT-default, D- Loopback0) list item forwards, and will enter label MT_default_SRGB_S [SID0_D] and is exchanged into outgoing label MT_blue_SRGB_ A[SID0_D]；If what S was received is IP messages, it is turned based on FTN for (MT-default, D-loopback0) list item Hair, the outgoing label MT_blue_SRGB_A [SID0_D] in pressure directly on IP heads.

It is MT_blue_SRGB_A [SID0_D] according to the top-level tab of message after step S503, A node receives message, ILM for (MT-blue, D-loopback0) list item is matched, is continued the top-level tab MT_blue_SRGB_A of message [SID0_D] issues B after being exchanged into MT_blue_SRGB_B [SID0_D].

Step S504, it is MT_blue_SRGB_B [SID0_D] according to the top-level tab of message after B node receives message, ILM for (MT-blue, D-loopback0) list item is matched, is continued the top-level tab MT_blue_SRGB_B of message [SID0_D] issues D after being exchanged into MT_blue_SRGB_D [SID0_D].

It is MT_blue_SRGB_D [SID0_D] according to the top-level tab of message after step S505, D node receives message, ILM for (MT-blue, D-loopback0) list item is matched, the local SR-LSP that terminates, is continued after peeling label off based on IP heads Forwarding, because IP heads are D-loopback0, then message up sending control plane.

Step S506, for the not a node level prefix on D nodes, for example can also be on D-loopback1, S node The foundation list item similar with D-loopback0, similar step S501, that is, assume that (MT-default, D-loopback1) is corresponding Prefix-sid be SID1_D, then above-mentioned each node be D-loopback0 establish list item in only need to change into SID0_D SID1_D.Related forwarding behavior also similar step S502~505, are repeated no more.

Preferably, can be only corresponding to node level prefix in MRT Island in embodiments of the present invention Prefix-sid is additionally based on MT-red SRGB and MT-blue SRGB generation MRT SR labels.Below to this optimization method Under each node how to establish corresponding list item for D-loopback1 and illustrate.Also will be according to this optimization side in other embodiments Method describes, and assumes that the loopback0prefix of each node is that node level prefix, other prefix are not a node level prefix。

It should be noted that a kind of Rule of judgment based on above-mentioned optimization method is：If prefix is the section in area Point level prefix and its advertizing node are the nodes in MRT Island, then are that the prefix establishes list item according to step 401, no Then S507 establishes list item in accordance with the following steps.

On step S507, S node, the MT-default next-hops in MT-default topologys to D-loopback1 are D, And the MT-blue paths (S-A-B-D) provided in MT-blue topologys are chosen to protect MT-default next-hop D, then MRT- FRR backup next-hops are MRT Egress nodes D and color-coded information is MRT-blue.Assuming that (MT-default, D- Loopback1) prefix-sid is SID1_D.The list item on part of nodes is illustrated below：

S nodes：

FTN for(MT-default,D-loopback1)

Main NHLFE：Next-hop is D, and outgoing label is MT_default_SRGB_D [SID1_D]

Standby NHLFE：It is MT_blue_SRGB_S [SID0_D] that top layer, which enters label,

Bottom outgoing label is MT_default_SRGB_D [SID1_D]

ILM for(MT-default,D-loopback1)

It is MT_default_SRGB_S [SID1_D] to enter label

Main NHLFE：Next-hop is D, and outgoing label is MT_default_SRGB_D [SID1_D]

Standby NHLFE：It is MT_blue_SRGB_S [SID0_D] that top layer, which enters label,

Bottom outgoing label is MT_default_SRGB_D [SID1_D]

ILM for(MT-blue,D-loopback0)

It is MT_blue_SRGB_S [SID0_D] to enter label

NHLFE：Next-hop is A, and outgoing label is MT_blue_SRGB_A [SID0_D]

D nodes：

ILM for(MT-default,D-loopback1)

It is MT_default_SRGB_D [SID1_D] to enter label

NHLFE：Nothing.Represent that SR-LSP has terminated.

Step S508, the message for being sent to destination D-loopback1, when link S-D breaks down, S nodes will As MRT ingress nodes by flow switch to preprepared to distal end MRT Egress nodes D MRT-blue roads Footpath, that is, start to forward message along MT-blue paths S-A-B-D.

If what S was received is MT-default SR label packets, it is based on ILM for (MT-default, D- Loopback1) list item forwards, and will enter label MT_default_SRGB_S [SID1_D] and is exchanged into outgoing label MT_default_ After SRGB_D [SID1_D], MT_blue_SRGB_A [SID0_D] is compressed, issues next-hop A；What if S was received is IP reports Text, then it is based on the forwarding of FTN for (MT-default, D-loopback1) list item, the outgoing label MT_ in pressure directly on IP heads After default_SRGB_D [SID1_D], MT_blue_SRGB_A [SID0_D] is compressed, issues next-hop A.

The processing that step S509, A node receives message is identical with step S503.

Step S510, the processing that B node receives message are identical with step S504.

After step S511, D node receives message, continuous bullet falls label MT_blue_SRGB_D [SID0_D] and MT_ Default_SRGB_D [SID1_D], continues to forward based on IP heads, and because IP heads are D-loopback0, then message up sending controls Plane.

According to above-described embodiment, it is known that message along MRT paths forward when, be actually along corresponding in MRT Island SR-LSP forwardings in MRT topologys, the wherein prefix of MRT Island interior nodes level are actually by MT-default SR- LSP and MT-blue or MT-red SR-LSP adhesions, and other prefix are actually to carry its MT-default SR-LSP On MT-blue the or MT-red SR-LSP to MRT Egress nodes.

Specific embodiment two

The MRT paths forwarding process that description purpose prefix is in outside MRT Island by the present embodiment, Fig. 6 are according to this The network topological diagram of invention specific embodiment two, as shown in fig. 6, OSPF is run in network, it is equal comprising two area, all nodes Enable Segment routing function under corresponding OSPF examples, S, A, B, C in wherein area1 are enabled to be determined in the embodiment of the present invention The MRT Profile of justice.S is established to destination node D prefix MRT paths as source node, is then based on this MRT path Protect SPF main paths.Comprise the following steps：

Enabled SR under the OSPF examples of all nodes in step S601, area1 and area2.

Enabled under the OSPF examples on each node of S, A, B, C in step S602, area1 defined in the embodiment of the present invention MRT Profile, then they a MRT Island is formed in area1.And used due to being specified in MRT Profile MRT SR-LSP based on multi-SRGB tunneling Option are as forwarding mechanism, then each node is except distribution Beyond MT-default SRGB, also additional allocation MT-red SRGB and MT-blue SRGB, such as can be on S nodes by this Three kinds of SRGB are designated as respectively：MT_default_SRGB_S [], MT_red_SRGB_S [], MT_blue_SRGB_S [].Other sections Point is similar.

The MT-default topologys that will be obtained on each node based on SPF algorithms in area, and obtained based on MRT algorithms MT-red and MT-blue topologys.For example be S-A to destination node A MT-default paths on S nodes, MT-blue paths Also it is S-A, and MT-red paths are S-C-B-A.

List item and embodiment one of each node for each node level prefix foundation in MRT Island in MRT Island Step S501 in for the prefix D-loopback0 list items established be all fours, and purpose IP matchings MRT The forwarding behavior of respective nodes level prefix flow is also all fours with step S502~505 in Island.It is no longer superfluous State.

On step S603, S node, the MT-default in MT-default topologys to prefix D-loopback0 is next Jump is C (assuming that advertizing nodes of the ABR1 as prefix D-loopback0 in area1, then use to destination node ABR1 MT-default paths determine next-hop).For prefix D-loopback0, it is assumed that use Tunnel Endpoint The distant-end node of Selection methods (referring to RFC7812) selection is A, it is assumed that in MRT Island S as GADAG root, And S<<A<<B<<C<<S, then it is S-A to node A MRT-blue paths, it can be used to protect above-mentioned MT-default next-hops C.The list item on part of nodes is illustrated below：

S nodes：

FTN for(MT-default,D-loopback0)

Main NHLFE：Next-hop is C, and outgoing label is MT_default_SRGB_C [SID0_D]

Standby NHLFE：It is MT_blue_SRGB_S [SID0_A] that top layer, which enters label,

Bottom outgoing label is MT_default_SRGB_A [SID0_D]

ILM for(MT-default,D-loopback0)

It is MT_default_SRGB_S [SID0_D] to enter label

Main NHLFE：Next-hop is C, and outgoing label is MT_default_SRGB_C [SID0_D]

Standby NHLFE：It is MT_blue_SRGB_S [SID0_A] that top layer, which enters label,

Bottom outgoing label is MT_default_SRGB_A [SID0_D]

ILM for(MT-blue,A-loopback0)

It is MT_blue_SRGB_S [SID0_A] to enter label

NHLFE：Next-hop is A, and outgoing label is MT_blue_SRGB_A [SID0_A]

A nodes：

ILM for(MT-blue,A-loopback0)

It is MT_blue_SRGB_A [SID0_A] to enter label

NHLFE：Nothing.Represent that SR-LSP has terminated.

ILM for(MT-default,D-loopback0)

It is MT_default_SRGB_A [SID0_D] to enter label

NHLFE：Next-hop is ABR3, and outgoing label is MT_default_SRGB_ABR3 [SID0_D]

ABR3 nodes：

ILM for(MT-default,D-loopback0)

It is MT_default_SRGB_ABR3 [SID0_D] to enter label

NHLFE：Next-hop is ABR2, and outgoing label is MT_default_SRGB_ABR2 [SID0_D]

ABR2 nodes：

ILM for(MT-default,D-loopback0)

It is MT_default_SRGB_ABR2 [SID0_D] to enter label

NHLFE：Next-hop is D, and outgoing label is MT_default_SRGB_D [SID0_D]

D nodes：

ILM for(MT-default,D-loopback0)

It is MT_default_SRGB_D [SID0_D] to enter label

NHLFE：Nothing.Represent that SR-LSP has terminated.

Step S604, the message for being sent to destination D-loopback0, when link S-C breaks down, S nodes will As MRT ingress nodes by flow switch to preprepared to distal end MRT Egress nodes A MRT-blue roads Footpath, that is, start to forward message along MT-blue paths S-A.

If what S was received is MT-default SR label packets, it is based on ILM for (MT-default, D- Loopback0) list item forwards, and will enter label MT_default_SRGB_S [SID0_D] and is exchanged into outgoing label MT_default_ After SRGB_A [SID0_D], MT_blue_SRGB_A [SID0_A] is compressed, issues next-hop A；What if S was received is IP reports Text, then it is based on the forwarding of FTN for (MT-default, D-loopback0) list item, the outgoing label MT_ in pressure directly on IP heads After default_SRGB_A [SID0_D], MT_blue_SRGB_A [SID0_A] is compressed, issues next-hop A.

After step S605, A node receives message, bullet falls label MT_blue_SRGB_A [SID0_A], by lower floor label MT_ Default_SRGB_A [SID0_D] issues next-hop ABR3 after being exchanged into MT_default_SRGB_ABR3 [SID0_D].

After step S606, ABR3 node receives message, label MT_default_SRGB_ABR3 [SID0_D] is exchanged into Next-hop ABR2 is issued after MT_default_SRGB_ABR2 [SID0_D].

After step S607, ABR2 node receives message, label MT_default_SRGB_ABR2 [SID0_D] is exchanged into Next-hop D is issued after MT_default_SRGB_D [SID0_D].

After step S608, D node receives message, bullet falls label MT_default_SRGB_D [SID0_D], based on IP heads after Continuous forwarding, because IP heads are D-loopback0, then message up sending control plane.

According to above-described embodiment, it is known that message along MRT paths forward when, be actually along corresponding in MRT Island SR-LSP forwardings in MRT topologys, after leaving MRT Island, it will be forwarded along the SR-LSP in acquiescence topology.Meet RFC7812 The forwarding rule of definition.

Specific embodiment three

The MRT paths forwarding process that description purpose prefix is in outside MRT Island by the present embodiment, in particular how Realize that the cross-domain forwarding that RFC7812 is defined is regular based on SR-LSP.Fig. 7 is the network topology according to the specific embodiment of the invention three Figure；As shown in fig. 7, running OSPF in network, comprising two area, all nodes enable segmentation under corresponding OSPF examples S, A, B, C in routing function, wherein area1 are enabled in MRT Profile, area2 defined in the embodiment of the present invention B, the MRT Profile defined in the similarly enabled embodiment of the present invention of E, D, F.S is established to destination node D as source node Prefix MRT paths, be then based on this MRT trail protection SPF main path.Comprise the following steps：

Enabled SR under the OSPF examples of all nodes in step S701, area1 and area2.

Enabled under the OSPF examples on each node of S, A, B, C in step S702, area1 defined in the embodiment of the present invention MRT Profile, then they a MRT Island is formed in area1.And used due to being specified in MRT Profile MRT SR-LSP based on multi-SRGB tunneling Option are as forwarding mechanism, then each node is except distribution Beyond MT-default SRGB, also additional allocation MT-red SRGB and MT-blue SRGB, such as can be by this on S nodes Three kinds of SRGB are designated as respectively：MT_default_SRGB_S [], MT_red_SRGB_S [], MT_blue_SRGB_S [].Other sections Point is similar.

The MT-default topologys that will be obtained on each node based on SPF algorithms in area, and obtained based on MRT algorithms MT-red and MT-blue topologys.For example be S-C-B to destination node B MT-default paths on S nodes, MT-red paths Also it is S-C-B, and MT-blue paths are S-A-B.

In MRT Island in area1 each node for each node level prefix is established in MRT Island list item with The step S501 of embodiment one is all fours, and purpose IP matches the stream of respective nodes level prefix in MRT Island The forwarding behavior of amount is also all fours with step S502~505.Repeat no more.

Also enable under the OSPF examples on each node of B, E, D, F in step S703, area2 and determine in the embodiment of the present invention Justice MRT Profile, then they a MRT Island is also formed in area2, corresponding MT- is generated in area2 Default topologys, and MT-red and MT-blue topologys.Assuming that shortest path next-hops of the B to D in acquiescence topology is F.

In MRT Island in area2 each node for each node level prefix is established in MRT Island list item with The step S501 of embodiment one is all fours, and purpose IP matches the stream of respective nodes level prefix in MRT Island The forwarding behavior of amount is also all fours with step S502~505.Repeat no more.

On step S704, S node, the MT-default in MT-default topologys to prefix D-loopback0 is next Jump is C (assuming that advertizing nodes of the ABR1 as prefix D-loopback0 in area1, then use to destination node ABR1 MT-default paths determine next-hop).For prefix D-loopback0, it is assumed that use Tunnel Endpoint The distant-end node of Selection methods (referring to RFC7812) selection is B, it is assumed that in MRT Island S as GADAG root, And S<<A<<B<<C<<S, then it is S-A-B to node B MRT-blue paths, it can be used to protect above-mentioned MT-default next Jump C.Assuming that (MT-default, D-loopback0) prefix-sid is SID0_D.The list item on part of nodes is carried out below Illustrate：

S nodes：

FTN for(MT-default,D-loopback0)

Main NHLFE：Next-hop is C, and outgoing label is MT_default_SRGB_C [SID0_D]

Standby NHLFE：It is MT_blue_SRGB_S [SID0_B] that top layer, which enters label,

Bottom outgoing label is MT_default_SRGB_B [SID0_D]

ILM for(MT-default,D-loopback0)

It is MT_default_SRGB_S [SID0_D] to enter label

Main NHLFE：Next-hop is C, and outgoing label is MT_default_SRGB_C [SID0_D]

Standby NHLFE：It is MT_blue_SRGB_S [SID0_B] that top layer, which enters label,

Bottom outgoing label is MT_default_SRGB_B [SID0_D]

ILM for(MT-blue,B-loopback0)

It is MT_blue_SRGB_S [SID0_B] to enter label

NHLFE：Next-hop is A, and outgoing label is MT_blue_SRGB_A [SID0_B]

A nodes：

ILM for(MT-blue,B-loopback0)

It is MT_blue_SRGB_A [SID0_B] to enter label

NHLFE：Next-hop is B, and outgoing label is MT_blue_SRGB_B [SID0_B]

B node：

ILM for(MT-blue,B-loopback0)

It is MT_blue_SRGB_B [SID0_B] to enter label

NHLFE：Nothing.Represent that SR-LSP has terminated.

ILM for(MT-default,D-loopback0)

It is MT_default_SRGB_B [SID0_D] to enter label

NHLFE：Next-hop is F, and outgoing label is MT_default_SRGB_F [SID0_D]

F nodes：

ILM for(MT-default,D-loopback0)

It is MT_default_SRGB_F [SID0_D] to enter label

NHLFE：Next-hop is D, and outgoing label is MT_default_SRGB_D [SID0_D]

D nodes：

ILM for(MT-default,D-loopback0)

It is MT_default_SRGB_D [SID0_D] to enter label

NHLFE：Nothing.Represent that SR-LSP has terminated.

Step S705, the message for being sent to destination D-loopback0, when link S-C breaks down, S nodes will As MRT ingress nodes by flow switch to preprepared to distal end MRT Egress nodes B MRT-blue roads Footpath, that is, start to forward message along MT-blue paths S-A-B.

If what S was received is MT-default SR label packets, it is based on ILM for (MT-default, D- Loopback0) list item forwards, and will enter label MT_default_SRGB_S [SID0_D] and is exchanged into outgoing label MT_default_ After SRGB_B [SID0_D], MT_blue_SRGB_A [SID0_B] is compressed, issues next-hop A；What if S was received is IP reports Text, then it is based on the forwarding of FTN for (MT-default, D-loopback0) list item, the outgoing label MT_ in pressure directly on IP heads After default_SRGB_B [SID0_D], MT_blue_SRGB_A [SID0_B] is compressed, issues next-hop A.

After step S706, A node receives message, label MT_blue_SRGB_A [SID0_B] is exchanged into MT_blue_ Next-hop B is issued after SRGB_B [SID0_B].

Step S707, after B node receives message, bullet falls label SRGB_B [default_SID0_B], by label MT_ Default_SRGB_B [SID0_D] issues next-hop F after being exchanged into MT_default_SRGB_F [SID0_D].

After step S708, F node receives message, label MT_default_SRGB_F [SID0_D] is exchanged into MT_ Next-hop D is issued after default_SRGB_D [SID0_D].

After step S709, D node receives message, bullet falls label MT_default_SRGB_D [SID0_D], based on IP heads after Continuous forwarding, because IP heads are D-loopback0, then message up sending control plane.

According to above-described embodiment, it is known that message along MRT paths forward when, in the MRT Island in area1 actually It is to be forwarded along the SR-LSP in corresponding MRT topologys, and leaves area1 into after area2, will turns along the SR-LSP in acquiescence topology Hair.Meet the forwarding rule that RFC7812 is defined.

Through the above description of the embodiments, those skilled in the art can be understood that according to above-mentioned implementation The method of example can add the mode of required general hardware platform to realize by software, naturally it is also possible to by hardware, but a lot In the case of the former be more preferably embodiment.Based on such understanding, technical scheme is substantially in other words to existing The part that technology contributes can be embodied in the form of software product, and the computer software product is stored in a storage In medium (such as ROM/RAM, magnetic disc, CD), including some instructions to cause a station terminal equipment (can be mobile phone, calculate Machine, server, or network equipment etc.) perform method described in each embodiment of the present invention.

A kind of apparatus for forwarding message is additionally provided in the present embodiment, and the device is used to realize above-described embodiment and preferred reality Mode is applied, had carried out repeating no more for explanation.As used below, term " module " can realize the soft of predetermined function The combination of part and/or hardware.Although device described by following examples is preferably realized with software, hardware, or The realization of the combination of software and hardware is also what may and be contemplated.

Fig. 8 is the structured flowchart of apparatus for forwarding message according to embodiments of the present invention, and the device can apply to first segment In point, as shown in figure 8, the device includes receiving module 82, searching modul 84 and forwarding module 86, the device is said below It is bright：

Receiving module 82, for receiving message to be forwarded, wherein, the destination address of the message is section point；Search Module 84, above-mentioned receiving module 82 is connected to, is opened up for searching target corresponding with above-mentioned message in the topology previously generated Flutter, wherein, the topology previously generated includes：Opened up according to the first topological sum second that maximum redundancy tree MRT algorithms generate to obtain Flutter, the 3rd topology obtained according to SPF SPF algorithms, the topology of above-mentioned first topological sum second and the 3rd topology that This is different；Forwarding module 86, above-mentioned searching modul 84 is connected to, is used to be forwarded to for searching in above-mentioned target topology The next-hop node of above-mentioned section point, and above-mentioned message is forwarded to next-hop node.In the present embodiment, forwarding module 86 Next-hop node can be forwarded the packet to based on predetermined forwarding mechanism, the predetermined forwarding mechanism, which uses, to be based on often being segmented per topology It route the Segment routing forwarding mechanism of global block SRGB tunnel nested mode.

In an optional embodiment, said apparatus also includes first processing module, for according to MRT algorithms from first Determine to be used to protect above-mentioned 3rd topology into the route of destination address into the route of destination address and the second topology in topology In to destination address route protection route, and determine the protection route corresponding to topology for protection topology；And/or according to Color-coded information determines to use into the route of termination point of a tunnel and the second topology from the first topology into the route of termination point of a tunnel It is route in the protection for protecting the route in the 3rd topology to destination address, and determines that topology corresponding to protection route is opened up for protection Flutter, wherein, the termination point of a tunnel is the distant-end node that first node selects for protection destination address, and the distant-end node is directed to Trouble point is no loop loop-free, and the first node is used to the MRT tunnels of the distant-end node and sealed when an error occurs Fill message.

In an optional embodiment, above-mentioned searching modul 84 can be in the following way in the topology previously generated Search target topology corresponding with above-mentioned message：Judge whether the link for being used to reach section point in above-mentioned 3rd topology goes out Existing failure；In the case where judging not break down, determine the 3rd topology for above-mentioned target topology；And/or judging In the case of failure, determine above-mentioned protection topology for target topology.

In an optional embodiment, said apparatus also includes Second processing module, for receiving institute to be forwarded Before stating message, generated to obtain first the second topology of topological sum according to MRT algorithms, and generate to obtain the 3rd according to SPF algorithms Topology.

In an optional embodiment, above-mentioned Second processing module can generate according to MRT algorithms in the following way The first topology of topological sum second is obtained, and is generated according to SPF algorithms to obtain the 3rd topology：Determine the MRT where first node Island, wherein, the MRT Island are by being in same domain area or same layer in first node and with first node Open Shortest Path First on secondary level other nodes (Open shortest Path First, referred to as OSPF) or Person's Intermediate System-to-Intermediate System (Intermediate system to Intermediate system, referred to as ISIS) is real Under example after enabled Segment routing SR and maximum redundancy tree configuration file MRT profile in the area where first node or Reciprocally negotiate what is formed by first node and other nodes in level；Based on above-mentioned MRT Island operation MRT algorithms generation the One the second topology of topological sum, and, based on the topology of above-mentioned area or level operation SPF algorithms generation the 3rd.

Specified in an optional embodiment, in above-mentioned MRT profile and use predetermined forwarding mechanism, i.e. in use The Segment routing forwarding mechanism for the tunnel nested mode based on the every Segment routing overall situation block SRGB of every topology stated.

In an optional embodiment, said apparatus also includes the 3rd processing module, for performing following operation at least One of：The first Segment routing overall situation block SRGB is distributed for the first topology, and by the first SRGB in the domain where MRT Island Flooded in area or level level；The second Segment routing overall situation block SRGB is distributed for the second topology, and by the 2nd SRGB in MRT Flooded in domain area or level level where Island；The 3rd Segment routing overall situation block SRGB is distributed for the 3rd topology, and will 3rd SRGB floods in all the domain area or level level where first node；Receive previously generating on other nodes Topological Segment routing overall situation block SRGB, record the topological SRGB previously generated on other nodes and by this other The topological SRGB previously generated on node continues to be advertised to the node in addition to other nodes.

In an optional embodiment, above-mentioned forwarding module 86 can forward the packet to next-hop in the following way Node：It is determined that the outgoing label of the first node matched with above-mentioned message；The outgoing label of above-mentioned first node is encapsulated on message, And the message after encapsulation is sent to next-hop node.

In an optional embodiment, above-mentioned forwarding module 86 can be determined as follows matched with message The outgoing label of one node：When above-mentioned target topology is topological for the 3rd, the topological outgoing label of the corresponding target of first node is by the Prefix index prefix-sid of one node based on purpose prefix prefix corresponding to destination address is corresponding with next-hop node What the SRGB of the 3rd topology was calculated.

In an optional embodiment, above-mentioned forwarding module 86 can also be determined as follows what is matched with message The outgoing label of first node：When above-mentioned target topology is the first topology or second is topological：If above-mentioned section point is MRT When purpose prefix prefix corresponding to node and destination address in Island is the node level prefix prefix of section point, It is determined as follows the outgoing label of the corresponding target topology of first node：The outgoing label of the corresponding target topology of first node By node level prefix prefix prefix index prefix-sid and pair of next-hop node of the first node based on section point The SRGB of target topology is answered to be calculated；If section point is not mesh corresponding to the node or destination address in MRT Island Prefix prefix be section point not a node level prefix prefix when, judge whether next-hop node is outside MRT Island Node；When judged result is no, the outgoing label of the corresponding target topology of first node is determined as follows：First segment The outgoing label of the corresponding target topology of point is label stack, and outer layer label is first node to the label of termination point of a tunnel, vpn label Label for termination point of a tunnel to purpose prefix prefix；Wherein, outer layer label is by node level of the first node based on termination point of a tunnel Prefix prefix prefix index prefix-sid and the target topology of the interior next-hop node to termination point of a tunnel of target topology SRGB is calculated, and vpn label is whole by prefix index prefix-sid of the first node based on purpose prefix prefix and tunnel The SRGB of 3rd topology of point is calculated；When judged result is to be, the corresponding mesh of first node is determined as follows Mark the outgoing label of topology：First node corresponding target topology outgoing label by first node based on purpose prefix prefix before Sew what the corresponding with next-hop node the 3rd topological SRGB of index prefix-sid were calculated.

In an optional embodiment, above-mentioned forwarding module 86 can also be at least one in the following way by first segment The outgoing label of point is encapsulated on above-mentioned message：When the type of message of above-mentioned message is Internet protocol IP message, in IP messages IP heads on the upper above-mentioned first node of pressure outgoing label；, will be upper when the type of message of message is Segment routing SR label packets The stack top tag replacement of the label stack of SR label packets is stated into the outgoing label of first node.

In an optional embodiment, above-mentioned forwarding module 86 can also be determined as follows going out for first node Label：When first node and section point are same node, then first node is based on the topological next-hop node determined of target For first node, the first node does not have outgoing label.That is, if above-mentioned first node is exactly section point, first node base In target topology determine next-hop node be exactly itself, now without outgoing label.

In an optional embodiment, said apparatus also includes fourth processing module, for when first node and second Following handle is performed when node is same node：When the type of message of message is Internet protocol IP message, by above-mentioned message On deliver to the control plane of first node；And/or when the type of message of above-mentioned message is Segment routing SR label packets, will The stack top label ejection of the label stack of SR label packets, and continue lower floor's label of the label stack based on above-mentioned message or IP heads are looked into Table forwards.

It should be noted that above-mentioned modules can be realized by software or hardware, for the latter, Ke Yitong Cross in the following manner realization, but not limited to this：Above-mentioned module is respectively positioned in same processor；Or above-mentioned modules are with any The form of combination is located in different processors respectively.

Embodiments of the invention additionally provide a kind of storage medium.Alternatively, in the present embodiment, above-mentioned storage medium can The program code for performing above steps to be arranged to storage to be used for.

Alternatively, in the present embodiment, above-mentioned storage medium can include but is not limited to：USB flash disk, read-only storage (Read- Only Memory, referred to as ROM), it is random access memory (Random Access Memory, referred to as RAM), mobile hard Disk, magnetic disc or CD etc. are various can be with the medium of store program codes.

Alternatively, in the present embodiment, processor performs above-mentioned each step according to the program code stored in storage medium Suddenly.

Alternatively, the specific example in the present embodiment may be referred to described in above-described embodiment and optional embodiment Example, the present embodiment will not be repeated here.

The breach that Segment routing combined with MRT technologies can have been filled up by the scheme in the embodiment of the present invention, be future The evolution of network provides valuable exploration.

Obviously, those skilled in the art should be understood that above-mentioned each module of the invention or each step can be with general Computing device realize that they can be concentrated on single computing device, or be distributed in multiple computing devices and formed Network on, alternatively, they can be realized with the program code that computing device can perform, it is thus possible to they are stored Performed in the storage device by computing device, and in some cases, can be with different from shown in order execution herein The step of going out or describing, they are either fabricated to each integrated circuit modules respectively or by multiple modules in them or Step is fabricated to single integrated circuit module to realize.So, the present invention is not restricted to any specific hardware and software combination.

The preferred embodiments of the present invention are the foregoing is only, are not intended to limit the invention, for the skill of this area For art personnel, the present invention can have various modifications and variations.Within the spirit and principles of the invention, that is made any repaiies Change, equivalent substitution, improvement etc., should be included in the scope of the protection.

Claims (14)

1. A kind of 1. message forwarding method, it is characterised in that including：

   First node receives message to be forwarded, wherein, the destination address of the message is section point；

   The first node searches target topology corresponding with the message in the topology previously generated, wherein, it is described advance The topology of generation includes：First the second topology of topological sum for generating to obtain according to maximum redundancy tree MRT algorithms, according to shortest path The 3rd topology that preferential SPF algorithms obtain, the second topological and described 3rd topology described in first topological sum each other it is each not It is identical；

   The first node is searched in the target topology for being forwarded to the next-hop node of the section point, and is based on The message is forwarded to the next-hop node by predetermined forwarding mechanism, wherein, the predetermined forwarding mechanism, which uses, to be based on often opening up Flutter the Segment routing forwarding mechanism of every Segment routing overall situation block SRGB tunnel nested mode.
2. 2. according to the method for claim 1, it is characterised in that methods described also includes：

   The first node according to the MRT algorithms from first topology to the route of the destination address and described second Determined in topology into the route of the destination address for protecting in the 3rd topology to the route of the destination address Protection route, and determine that topology corresponding to the protection route is protection topology；And/or

   The first node is opened up according to color-coded information from first topology to the route of termination point of a tunnel and described second Flutter into the route of termination point of a tunnel determine for protect in the 3rd topology to the destination address route protection road By, and determine that topology corresponding to the protection route is protection topology, wherein, the termination point of a tunnel is that the first node is guarantor The distant-end node for protecting destination address and selecting, the distant-end node are no loop loop-free for trouble point, when event The first node is used to the MRT tunnel encapsulation messages of the distant-end node when barrier occurs.
3. 3. according to the method for claim 2, it is characterised in that the first node is searched in the topology previously generated and Target topology includes corresponding to the message：

   The first node judges whether the link for being used to reach the section point in the 3rd topology breaks down；

   In the case where judging not break down, the first node determines the 3rd topology for target topology； And/or

   In the case where judging failure, the first node determines the protection topology for target topology.
4. 4. according to the method for claim 1, it is characterised in that the first node receive the message to be forwarded it Before, methods described also includes：

   The first node generates to obtain the topology of the first topological sum second according to the MRT algorithms, and according to the SPF Algorithm generates to obtain the 3rd topology.
5. 5. according to the method for claim 4, it is characterised in that the first node generates to obtain according to the MRT algorithms The topology of first topological sum second, and generate to obtain the 3rd topology according to the SPF algorithms and include：

   The first node determines the MRT Island where the first node, wherein, the MRT Island be by The first node and the opening being in the first node on same domain area or same levels level other nodes Segment routing SR and maximum redundancy tree are enabled under SPF OSPF or Intermediate System-to-Intermediate System ISIS examples After configuration file MRT profile in the area or level where the first node by the first node and it is described its He reciprocally negotiates what is formed by node；

   The first node is opened up based on described in the MRT Island operations MRT algorithms generation first topological sum second Flutter, and, the SPF algorithms generation the 3rd topology is run based on the area or level.
6. 6. according to the method for claim 5, it is characterised in that specified in the MRT profile using described predetermined turn Hair mechanism.
7. 7. according to the method for claim 5, it is characterised in that methods described also includes at least one of：

   The first node is that the described first topology distributes the first Segment routing overall situation block SRGB, and by the first SRGB in institute State and flooded in domain area or level level where MRT Island；

   The first node is that the described second topology distributes the second Segment routing overall situation block SRGB, and by the 2nd SRGB in institute State and flooded in domain area or level level where MRT Island；

   The first node is that the described 3rd topology distributes the 3rd Segment routing overall situation block SRGB, and by the 3rd SRGB in institute State and flooded in all domain area or level level where first node；

   The first node receives the topological Segment routing overall situation block SRGB previously generated on other nodes, records institute State the topological SRGB previously generated on other nodes and opened up what is previously generated described on other described nodes The SRGB flutterred continues to be advertised to the node in addition to other described nodes.
8. 8. according to the method for claim 1, it is characterised in that the message is forwarded to described next by the first node Hop node includes：

   The first node determines the outgoing label of the first node matched with the message；

   The outgoing label of the first node is encapsulated on the message by the first node, and the message after encapsulation is sent to The next-hop node.
9. 9. according to the method for claim 8, it is characterised in that the first node determination matches described with the message The outgoing label of first node includes：

   When target topology is topological for the described 3rd, the outgoing label of the correspondence target topology of the first node is by institute First node is stated based on purpose prefix prefix prefix index prefix-sid corresponding to destination address and the next-hop section What the SRGB of correspondence the 3rd topology of point was calculated.
10. 10. according to the method for claim 8, it is characterised in that the first node determines the institute matched with the message Stating the outgoing label of first node includes：

    When the target topology for described first it is topological or it is described second it is topological when：

    If the section point is purpose prefix corresponding to the node in the MRT Island and the destination address When prefix is the node level prefix prefix of the section point, the first node is determined as follows described first The outgoing label of the correspondence target topology of node：The outgoing label of the correspondence of the first node target topology is by described the Node level prefix prefix of one node based on section point prefix index prefix-sid and the next-hop node The SRGB of correspondence target topology be calculated；

    If the section point is not purpose prefix corresponding to the node in the MRT Island or the destination address When prefix is the not a node level prefix prefix of the section point, whether the first node judges the next-hop node For the node outside the MRT Island；

    When judged result is no, the correspondence target that the first node is determined as follows the first node is opened up The outgoing label flutterred：The outgoing label of the correspondence target topology of the first node is label stack, and outer layer label is described first For node to the label of termination point of a tunnel, vpn label is label of the termination point of a tunnel to the purpose prefix prefix；Wherein, institute State prefix index prefix- of the outer layer label by node level prefix prefix of the first node based on the termination point of a tunnel Sid and the SRGB of the extremely target topology of the next-hop node of the termination point of a tunnel in target topology are calculated, institute Vpn label is stated by prefix index prefix-sid of the first node based on the purpose prefix prefix and the tunnel The SRGB of 3rd topology of terminal is calculated；

    In judged result for when being, the correspondence target that the first node is determined as follows the first node is opened up The outgoing label flutterred：Before the outgoing label of the correspondence target topology of the first node is based on the purpose by the first node The SRGB for sewing prefix prefix index prefix-sid the 3rd topologys corresponding with the next-hop node is calculated 's.
11. 11. according to the method for claim 8, it is characterised in that the first node is by the outgoing label of the first node Being encapsulated on the message includes at least one of：

    When the type of message of the message is Internet protocol IP message, on the IP heads of the IP messages described first in pressure The outgoing label of node；

    When the type of message of the message is Segment routing SR label packets, by the stack top of the label stack of the SR label packets Outgoing label of the tag replacement into the first node.
12. 12. according to the method for claim 8, it is characterised in that the first node determines the bid of the first node Label include：

    When the first node and the section point are same node, then the first node is based on target topology really The fixed next-hop node is the first node, and the first node does not have outgoing label.
13. 13. according to the method for claim 1, it is characterised in that methods described also includes：

    When the first node and the section point are same node, including：When the type of message of the message is interconnection During fidonetFido IP messages, control plane of the first node by the message up sending to the first node；And/or work as institute When the type of message for stating message is Segment routing SR label packets, the first node is by the label stack of the SR label packets Stack top label ejects, and continues lower floor's label of the label stack based on the message or IP heads are tabled look-up forwarding.
14. A kind of 14. apparatus for forwarding message, it is characterised in that applied in first node, including：

    Receiving module, for receiving message to be forwarded, wherein, the destination address of the message is section point；

    Searching modul, for searching target topology corresponding with the message in the topology previously generated, wherein, it is described advance The topology of generation includes：First the second topology of topological sum for generating to obtain according to maximum redundancy tree MRT algorithms, according to shortest path The 3rd topology that preferential SPF algorithms obtain, the second topological and described 3rd topology described in first topological sum each other it is each not It is identical；

    Forwarding module, for searching the next-hop node for being forwarded to the section point, and base in the target topology The message is forwarded to the next-hop node in predetermined forwarding mechanism, wherein, the predetermined forwarding mechanism is used based on every Segment routing forwarding mechanism of the topology per Segment routing overall situation block SRGB tunnel nested mode.