CN109005109B - Route setting method and multicast networking system - Google Patents
Route setting method and multicast networking system Download PDFInfo
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- CN109005109B CN109005109B CN201810820267.3A CN201810820267A CN109005109B CN 109005109 B CN109005109 B CN 109005109B CN 201810820267 A CN201810820267 A CN 201810820267A CN 109005109 B CN109005109 B CN 109005109B
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- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L45/00—Routing or path finding of packets in data switching networks
- H04L45/38—Flow based routing
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L45/00—Routing or path finding of packets in data switching networks
- H04L45/28—Routing or path finding of packets in data switching networks using route fault recovery
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L45/00—Routing or path finding of packets in data switching networks
- H04L45/74—Address processing for routing
- H04L45/745—Address table lookup; Address filtering
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L47/00—Traffic control in data switching networks
- H04L47/70—Admission control; Resource allocation
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- H04L47/806—Broadcast or multicast traffic
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Abstract
The present disclosure provides a routing setting method and a multicast networking, wherein the multicast networking comprises a first multicast routing device and a target rendezvous point corresponding to a target multicast group. The target rendezvous point receives multicast traffic forwarded by the first multicast routing equipment through different paths, and when the received multicast traffic is detection traffic including detection marks, RPF routing corresponding to a source address of the detection traffic and multicast routing corresponding to a destination address of the detection traffic are searched in the target rendezvous point; and setting the interface of the target convergent point for receiving the detection flow as a backup RPF interface in the searched RPF route, and setting the interface of the target convergent point for receiving the detection flow as a backup interface in the searched multicast route, so that the multicast flow with the forwarding path consistent with the detection flow can pass the RPF check on the target convergent point.
Description
Technical Field
The present disclosure relates to the field of communications technologies, and in particular, to a routing setting method and a multicast networking system.
Background
PIM-SM (Protocol Independent Multicast-Sparse Mode) is a Multicast routing Protocol in a Sparse Mode, and a core task of implementing Multicast forwarding is to construct and maintain an RPT (Rendezvous Point Tree). The RPT selects a certain routing device as a common root node RP (Rendezvous Point), and requests a receiver of multicast data and a multicast source sending the multicast data to realize forwarding of the multicast data by interacting with the RP.
The multicast data sent by the multicast source to any multicast group is sent to the RP corresponding to the multicast group first, and then the RP distributes the multicast data along the RPT of the multicast group. When a forwarding path between a multicast source and an RP fails, multicast data packet loss may result. By adding the backup forwarding path, when the original forwarding path fails, the multicast data can be quickly switched to the backup forwarding path for forwarding.
However, when receiving multicast data, the routing device performs RPF (Reverse Path Forwarding) check on the multicast data to determine whether an interface receiving the multicast data is on the shortest Path from the routing device to the multicast source, and if so, the routing device forwards the multicast data, but the multicast data forwarded from the backup Forwarding Path is unlikely to pass the RPF check, and finally packet loss still occurs.
Disclosure of Invention
In view of the above, an object of the present disclosure is to provide a routing method and a multicast networking system, so as to at least partially improve the above problems.
In order to achieve the above purpose, the embodiment of the present disclosure adopts the following technical solutions:
in a first aspect, an embodiment of the present disclosure provides a route setting method, which is applied to a multicast networking system, where the multicast networking system includes a first multicast routing device and a target rendezvous point corresponding to a target multicast group, and the method includes:
the target rendezvous point receives multicast traffic forwarded by the first multicast routing equipment through different paths, and when the received multicast traffic is detection traffic including detection marks, reverse path forwarding RPF routing corresponding to a source IP address of the detection traffic and multicast routing corresponding to a destination IP address of the detection traffic are searched in the target rendezvous point;
setting the interface of the target rendezvous point receiving the detection flow as a backup RPF interface in the searched RPF route, and setting the interface of the target rendezvous point receiving the detection flow as a backup interface in the searched multicast route, so that the multicast flow with the same forwarding path as the detection flow can pass RPF check on the target rendezvous point.
In a second aspect, an embodiment of the present disclosure provides a multicast networking system, where the multicast networking system includes a first multicast routing device and a target rendezvous point corresponding to a target multicast group; the target convergence point includes:
a first receiving module, configured to receive multicast traffic forwarded by a first multicast routing device through different forwarding paths, and when the received multicast traffic is probe traffic including a probe mark, search, in the target rendezvous point, for an RPF route corresponding to a source IP address of the probe traffic and a multicast route corresponding to a destination IP address of the probe traffic;
a first setting module, configured to set, in the found RPF route, an interface where the target rendezvous point receives the probe traffic as a backup RPF interface, and set, in the found multicast route, an interface where the target rendezvous point receives the probe traffic as a backup ingress interface, so that the multicast traffic received by the target rendezvous point and forwarded through the backup forwarding path can pass RPF inspection.
Compared with the prior art, the embodiment of the disclosure has the following beneficial effects:
the embodiment of the disclosure provides a route setting method and a multicast networking system, wherein the multicast networking system (hereinafter referred to as a multicast networking system) comprises a first multicast routing device and a target rendezvous point corresponding to a target multicast group. When receiving the multicast traffic forwarded by the first multicast routing device through different forwarding paths, the target rendezvous point searches for an RPF route corresponding to a source IP address of the detection traffic and a multicast route corresponding to a destination IP address of the detection traffic in the target rendezvous point when the received multicast traffic is the detection traffic including the detection mark. And setting an interface of the target rendezvous point receiving the flow as a backup RPF interface in the searched RPF route, and setting an interface of the target rendezvous point receiving the detection flow as a backup interface in the searched multicast route, so that the multicast flow with the same forwarding path as the detection flow can pass the RPF check on the target rendezvous point. Therefore, when the main forwarding path fails, the multicast traffic forwarded from other forwarding paths can be prevented from being discarded because the multicast traffic cannot pass the RPF check.
Drawings
To more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present disclosure and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings may be obtained from the drawings without inventive effort.
Fig. 1 is a schematic connection diagram of a multicast networking provided in an embodiment of the present disclosure;
fig. 2 is a schematic flow chart of a route setting method according to an embodiment of the present disclosure;
fig. 3 is a schematic diagram of multicast networking in a specific example provided by the embodiment of the present disclosure;
fig. 4 is a schematic flowchart of a route setting method applied to the multicast networking shown in fig. 3 according to an embodiment of the present disclosure;
fig. 5 is a second flowchart of a route setting method applied to the multicast networking shown in fig. 3 according to the embodiment of the present disclosure;
fig. 6 is a functional block diagram of a multicast networking according to an embodiment of the present disclosure.
Icon: 10. 30-multicast networking; 100-a first multicast routing device; 110-a second setup module; 120-a sending module; 200-a second multicast routing device; 210-a second receiving module; 220-a third setup module; 300-target convergence point; 310-a first receiving module; 320-a first setup module; 40-a multicast source; 50-multicast group.
Detailed Description
To make the objects, technical solutions and advantages of the embodiments of the present disclosure more clear, the technical solutions of the embodiments of the present disclosure will be described clearly and completely with reference to the drawings in the embodiments of the present disclosure, and it is obvious that the described embodiments are some, but not all embodiments of the present disclosure. The components of the embodiments of the present disclosure, generally described and illustrated in the figures herein, can be arranged and designed in a wide variety of different configurations.
Thus, the following detailed description of the embodiments of the present disclosure, presented in the figures, is not intended to limit the scope of the claimed disclosure, but is merely representative of selected embodiments of the disclosure. All other embodiments, which can be derived by a person skilled in the art from the embodiments disclosed herein without making any creative effort, shall fall within the protection scope of the present disclosure.
It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.
Fig. 1 is a schematic diagram of a multicast network 10 according to an embodiment of the present disclosure. The multicast network 10 includes a first multicast routing device 100 and a target rendezvous point 300 (RP) corresponding to a target multicast group. The first multicast routing device 100 may be any multicast routing device between the multicast source and the destination rendezvous point 300. For example, the first multicast routing device 100 may be a multicast routing device directly connected to a multicast source, for example, a DR (Designated Router). In this case, a backup forwarding path from the multicast source to the target rendezvous point 300 can be created by the route setup method provided by the present disclosure.
The multicast routing device refers to a device (such as a router or a three-layer switch) running a multicast routing protocol. In this embodiment, the multicast routing protocol may be PIM-SM.
In practical application, for each multicast group, a corresponding multicast routing device is selected as a rendezvous point of the multicast group, and a multicast source firstly sends multicast traffic sent to the multicast group to the rendezvous point of the multicast group and then forwards the multicast traffic to each member in the multicast group. For example, in the scenario shown in fig. 1, the target rendezvous point 300 is a multicast routing device in the multicast network 10. Correspondingly, in implementation, the first multicast routing device 100 sends the multicast traffic addressed to the target multicast group to the target rendezvous point 300, and then the target rendezvous point 300 sends the multicast traffic to each member of the target multicast group. In some embodiments, the first multicast routing device 100 generally forwards the multicast traffic only to the target rendezvous point 300 along the optimal path, and when the optimal path or a node thereon fails, the multicast data sent to the target multicast group will be lost.
In order to improve the above problem, the embodiments of the present disclosure provide a routing method and a multicast network 10, which will be described in detail below.
As shown in fig. 2, the flowchart of a route setting method provided by the embodiment of the present disclosure is illustrated, and is applied to the multicast network 10 shown in fig. 1, where a forwarding information table of each multicast routing device in the multicast network 10 stores a unicast route and a target multicast route using an IP address of a target multicast group as a destination address. The route setting method will be explained in detail with reference to fig. 2, and is described in detail as follows.
Step S21, the first multicast routing device 100 searches for a unicast route using the IP address of the target rendezvous point 300 as the destination address in a forwarding information table of the device, and sets an egress interface corresponding to a backup next hop of the found unicast route as a backup egress interface of the target multicast route, so as to forward the multicast traffic using the IP address of the target multicast group as the destination address through the backup egress interface when a failure occurs in the primary forwarding path between the first multicast routing device 100 and the target rendezvous point 300.
The unicast route issued to the forwarding information table is the optimal route determined by calculation. In the embodiment of the present disclosure, each multicast routing device operates a corresponding unicast routing protocol and starts an IP FRR function, so that each multicast routing device automatically calculates an optimal next hop and a next hop without a loop, sets the optimal next hop as a primary next hop of a unicast route, and sets the next hop as a backup next hop in the unicast route.
In the embodiment of the present disclosure, the active next hop is a next hop with an "active" flag, and the backup next hop is a next hop with a "backup int" flag. The output interface of the multicast router connected with the main next hop is the main output interface, and the output interface of the multicast router connected with the backup next hop is the backup output interface.
In implementation, for a target multicast group for which a backup forwarding path needs to be established, the first multicast routing device 100 may determine, according to an IP address of the target multicast group, an IP address of a target rendezvous point 300 corresponding to the target multicast group. In the multicast group network 10 including the rendezvous point, the RP is dynamically selected for each multicast group and advertised to each routing device in the group network, so that each routing device in the group network can determine the RP of different multicast groups.
After determining the IP address of the target aggregation point 300, a unicast route with the IP address as a destination address is searched. Obtaining the next hop of next hop in the found unicast route, determining the outgoing interface corresponding to the next hop of next hop on the first multicast routing device 100, setting the outgoing interface as a backup outgoing interface in the target multicast route, and setting the existing outgoing interface in the target multicast route as a main outgoing interface.
Optionally, in this embodiment, step S21 may be implemented by the following sub-steps:
the first multicast routing device 100 determines the IP address of the target rendezvous point 300 according to the destination IP address of the target multicast route at preset time intervals, and searches a unicast route using the IP address of the target rendezvous point 300 as the destination IP address in a forwarding information table of the device.
In this embodiment of the present disclosure, a destination address of each target multicast route stored in the first multicast routing device 100 may be periodically obtained, where the destination address is an IP address of a target multicast group corresponding to the target multicast route, and therefore, the IP address of the corresponding target rendezvous point 300 may be determined according to the obtained destination address, and a unicast route using the IP address of the target rendezvous point 300 as the destination address is further searched.
Alternatively, in this embodiment, step S21 may also be implemented by the following sub-steps:
when receiving the multicast traffic sent by the multicast source to the target multicast group, the first multicast routing device 100 determines the IP address of the target rendezvous point 300 according to the destination address of the multicast traffic, and searches a unicast route using the IP address of the target rendezvous point 300 as the destination address in a forwarding information table of the first multicast routing device 100.
Based on the above analysis, the first multicast routing device 100 may set a backup outgoing interface in the target multicast route periodically, or may set a backup outgoing interface in the target multicast route matching the destination address of the multicast traffic when receiving the multicast traffic.
Optionally, in this embodiment, the route setting method may further include the following steps:
when finding out the unicast route using the IP address of the target rendezvous point 300 as the destination address, the first multicast routing device 100 sets the outgoing interface corresponding to the active next hop of the unicast route as the active outgoing interface of the target multicast route.
Therefore, when the backup output interface is set, the main output interface can be correspondingly updated so as to ensure that the main output interface is the current optimal output interface.
In step S22, when receiving the multicast traffic sent by the multicast source to the target multicast group, the first multicast routing device 100 adds a probe mark to the multicast traffic to form a probe traffic, and forwards the probe traffic through the backup output interface, so as to establish an optimal forwarding path of the multicast traffic between the first multicast routing device 100 and the target rendezvous point 300 as a backup forwarding path.
In this embodiment, when the first multicast routing device 100 receives a multicast traffic from a multicast source to a target multicast group, it searches for a target multicast route matching the destination address of the multicast traffic. If the main forwarding path corresponding to the main outgoing interface of the searched multicast route does not have a fault, the first multicast routing device 100 forwards the multicast traffic from the main outgoing interface. Meanwhile, the first multicast routing device 100 may copy a copy of the multicast traffic, add the detection flag to the multicast traffic to form a detection traffic, and forward the detection traffic through a backup egress interface set in the searched target multicast route.
The detection mark may be any identifier set in advance, and the disclosure is not limited thereto.
The next-hop multicast routing device connected to the backup output interface may be notified through the probe traffic to also perform setting of the backup output interface, and the next-hop multicast routing device may further forward the probe traffic through the set backup output interface, so that an optimal forwarding path of the multicast traffic may be established between the first multicast routing device 100 and the target rendezvous point 300 as a backup forwarding path, and the multicast traffic may be forwarded through the backup forwarding path when the primary forwarding path or any node thereon fails.
Optionally, referring to fig. 1 again, in the embodiment of the present disclosure, the multicast networking 10 may further include a second multicast routing device 200 located on the backup forwarding path. The aforementioned next-hop routing devices corresponding to the backup outgoing interface are all the second multicast routing devices 200. Correspondingly, the route setting method may further include step S23 and step S24.
In step S23, when the second multicast routing device 200 receives the probe traffic, a unicast route with the IP address of the target rendezvous point 300 as the destination address is sent to the forwarding information table of the second multicast routing device 200, and a multicast route is newly established in the forwarding information table of the second multicast routing device 200 according to the probe traffic.
The IP address of the target rendezvous point 300 may be the IP address of the multicast routing device corresponding to the target rendezvous point 300, or may be the IP address of a lookup back interface on the multicast routing device corresponding to the target rendezvous point 300.
In step S24, the second multicast routing device 200 sets the interface that receives the probe traffic as a backup ingress interface of the newly-built multicast route, sets the egress interface corresponding to the primary next hop of the found unicast route as a backup egress interface of the newly-built multicast route, and forwards the probe traffic through the backup egress interface.
In the embodiment of the present disclosure, since the second multicast routing device 200 is not included in the optimal path from the first multicast routing device 100 to the target rendezvous point 300, there is no multicast route in the second multicast routing device 200 that takes the IP address of the target multicast group as the destination address. Therefore, it is necessary to newly establish a multicast route in the second multicast routing device 200 according to the probe traffic. In detail, the newly-built target multicast route: and taking the destination address of the detection flow as a destination address, taking the source address of the detection flow as a source address, and taking an interface which the detection flow actually reaches as an incoming interface.
Since the probe traffic itself is addressed to the target multicast group, the finally created multicast route is also the target multicast route using the IP address of the target multicast group as the destination address.
In addition, since the second multicast routing device 200 is already located on the backup forwarding path, the optimal egress interface of the second multicast routing device 200 reaching the target rendezvous point 300 may be set as the egress interface of the newly-built multicast route, and a backup (backup int) flag is added, that is, the egress interface corresponding to the active next hop in the found unicast route is set as the backup egress interface of the newly-built multicast route.
And after a backup output interface is set in the newly-built target multicast route, continuously forwarding the detection flow through the backup output interface so as to trigger next-hop routing equipment of the backup output interface to continuously set the backup output interface. Finally, the probe traffic is forwarded to the target rendezvous point 300, thereby achieving establishment of a backup forwarding path.
In this way, when the first multicast routing device 100 receives a multicast traffic sent by a multicast source to a target multicast group, it searches for a target multicast route matching with a destination address of the multicast traffic, and if it is detected that a primary output interface in the target multicast route fails or a primary forwarding path corresponding to the primary output interface fails, the multicast traffic may be forwarded through a backup output interface in the target multicast route, so that the multicast traffic is forwarded to the target rendezvous point 300 through the backup forwarding path.
However, it has been found through research that in the multicast network 10, the multicast router performs RPF check on the received multicast traffic to ensure that the multicast traffic can be transmitted along the correct path and to avoid loops due to various reasons. If the RPF check is passed, the multicast routing device will forward the multicast traffic, and if the RPF check fails, the multicast traffic will be discarded. The specific process of the multicast routing device for performing the RPF check is as follows:
and determining an optimal route as an RPF route by taking the IP address of the message source as a destination address, wherein the RPF route comprises an RPF interface, and the RPF interface is an output interface corresponding to the optimal path from the multicast routing equipment to the message source. If the current multicast flow is transmitted from the multicast source to the RP, the RPF check is carried out by taking the multicast source as a message source.
In this case, although a backup forwarding path is established between the first multicast routing device 100 and the target rendezvous point 300, when multicast traffic is forwarded to the target rendezvous point 300 through the backup forwarding path, the multicast traffic cannot be discarded because the multicast traffic cannot pass the RPF check, and the problem of packet loss due to link failure cannot be solved.
Based on the above problems, through research on the RPF check process, in practical application, because performing RPF check on each received multicast traffic would bring a large burden to the multicast routing device, when the multicast routing device receives the multicast traffic of the multicast group from the multicast source sending network, it would find out whether there is a multicast route corresponding to the multicast traffic in the multicast forwarding table:
if not, determining the RPF route according to the source address of the multicast flow, taking an RPF interface in the RPF route as an input interface, creating a multicast route by combining related route information, issuing the created multicast route to a multicast forwarding table, and performing RPF check on the multicast flow: when the actual arrival interface of the multicast flow is the RPF interface, the RPF checks to pass and forwards the multicast flow; when the actual arrival interface of the multicast flow is not the RPF interface, the RPF check fails, and the multicast flow is discarded;
if yes, judging whether the interface actually reached by the multicast flow is the input interface of the multicast route, if yes, directly forwarding the multicast flow; if not, checking whether the RPF interface is consistent with the input interface of the multicast route; if the multicast flow is consistent with the multicast flow, determining that the multicast route is correct, and discarding the multicast flow; if not, determining that the multicast route is outdated, setting an incoming interface of the multicast route as the RPF interface, and rechecking whether an interface actually reached by the multicast traffic is the RPF interface, if so, forwarding the multicast traffic, and if not, discarding the multicast traffic.
Therefore, to ensure that the multicast traffic passes the RPF check, it is necessary to keep the RPF interface in the RPF route corresponding to the source address of the multicast traffic, the ingress interface in the multicast route corresponding to the destination address of the multicast traffic, and the interface at which the multicast traffic is actually received by the multicast routing device all the same.
Based on this, the route setting method provided by the embodiment of the present disclosure further includes step S25 and step S26.
Step S25, the target rendezvous point 300 receives the multicast traffic forwarded by the first multicast routing device 100 through different paths, and when the received multicast traffic is probe traffic including a probe mark, searches for an RPF route corresponding to a source address of the probe traffic and a multicast route corresponding to a destination address of the probe traffic in the target rendezvous point 300.
Based on the foregoing description, when receiving the multicast traffic, the first multicast routing device 100 searches for a target multicast route matching the multicast traffic. After the target multicast route is found, on one hand, the multicast flow is forwarded from the main outgoing interface of the target multicast route, on the other hand, a detection mark is added to the multicast flow to form a detection flow, and the detection flow is forwarded through a backup outgoing interface in the target multicast route. In other words, the target rendezvous point 300 will receive multicast traffic over two paths. And the received multicast traffic including the detection mark is the detection traffic. In implementation, when the multicast traffic received by the target rendezvous point 300, it is detected whether the multicast traffic includes a probe flag, and if so, it may be determined that the multicast traffic is the probe traffic.
In this disclosure, the RPF route is an optimal route from the current multicast routing device to the multicast source, and the RPF route includes an RPF interface, that is, an egress interface corresponding to the active next hop of the optimal route.
Step S26, in the found RPF route, setting the interface of the target rendezvous point 300 that receives the probe traffic as a backup RPF interface, and in the found multicast route, setting the interface of the target rendezvous point 300 that receives the probe traffic as a backup ingress interface, so that the multicast traffic whose forwarding path is the same as the probe traffic can pass the RPF check on the target rendezvous point 300.
In view of the fact that the probe traffic is forwarded from the first multicast routing device 100 to the backup forwarding path of the target rendezvous point 300, with the above configuration, when the target rendezvous point 300 receives the multicast traffic forwarded by the first multicast routing device 100 through the backup forwarding path, an interface actually reached by the multicast traffic can be kept consistent with the backup RPF interface in the RPF route and the backup ingress interface in the corresponding multicast route, so that the multicast traffic can be forwarded to each member of the target multicast group by the target rendezvous point 300 along the RPT through the RPF check.
It should be noted that, in the embodiment of the present disclosure, the second multicast routing device 200 also performs RPF check when receiving the multicast traffic, however, since the backup forwarding path is a sub-optimal path from the first multicast routing device 100 to the target rendezvous point 300, for the second multicast routing device 200 located on the backup forwarding path, the backup forwarding path is an optimal path to reach the multicast source. In this case, the multicast traffic received by the second multicast routing device 200 from the backup forwarding path will be able to automatically pass the RPF check, and no additional setup may be necessary.
Through the above process, when the primary forwarding path from the first multicast routing device 100 to the target rendezvous point 300 fails, the primary forwarding path can be switched to the backup forwarding path to forward the multicast traffic, so that packet loss of the multicast traffic is avoided.
A specific example is given below in conjunction with the multicast networking 30 shown in fig. 3 to further explain the route setting method provided by the embodiment of the present disclosure, and the specific description is as follows.
First, briefly describing the multicast networking 30 shown in fig. 3, the multicast networking 30 includes a multicast router R1, a multicast router R2, and a multicast router DUT, where the multicast router R2 is directly connected to the multicast source 40, the multicast router DUT is an RP corresponding to the multicast group 50, and an optimal interface from the multicast router R2 to the multicast router DUT is a. The multicast routing device R2 serves as the first multicast routing device 100 described in this embodiment, and the multicast routing device R1 serves as the second multicast routing device 200 described in this embodiment.
The multicast routing equipment R1, the multicast routing equipment R2 and the multicast routing equipment DUT all start an IP FRR function, and based on the function, unicast routes in the FIBs of the multicast routing equipment R1, the multicast routing equipment R2 and the multicast routing equipment DUT all comprise an active next hop and a backup next hop.
In this embodiment, it is assumed that the IP address of the multicast source 40 is 172.168.0.2 and the IP address of the multicast group 50 is 227.0.0.1. The FIB of the multicast router R2 stores a multicast route M1 having 172.168.0.2 as a destination address, which is the target multicast route described above.
In the multicast network 30, a backup forwarding path from the multicast router R2 to the multicast router DUT may be established through the steps shown in fig. 4 and fig. 5, and it is ensured that multicast traffic arriving at the multicast router DUT from the backup forwarding path can be checked by the RPF.
In step S41, the multicast router R2 obtains the destination address 172.168.0.2 of the multicast router M1 at preset time intervals for the stored multicast router M1, determines the IP address of the RP corresponding to 172.168.0.2 (multicast source), and searches for the unicast router N1 using the IP address of the multicast router DUT as the destination address.
The determined IP address of the RP may be an IP address of the multicast routing device DUT, or an IP address of a lookup back interface on the multicast routing device DUT.
Further, when receiving the multicast traffic addressed to 172.168.0.2, the multicast router 42 may determine the IP address of the RP 172.168.0.2 corresponding to the received multicast traffic, and search for the unicast route N1 from the IP address of the RP.
Step S42, the multicast routing device R2 determines that the outgoing interface on the device corresponding to the backup next hop in the unicast routing N1 is the B interface, determines that the outgoing interface on the device corresponding to the Active next hop in the unicast routing N1 is the a interface, sets the a interface and the B interface to the outgoing interface list of the multicast routing M1, adds an Active flag to the a interface, and adds a backup int flag to the B interface.
Step S43, when receiving the multicast traffic F1 sent by the multicast source 40 to the multicast group 50, the multicast router R2 finds the multicast route M1 using the IP address 227.0.0.1 of the multicast group 50 as the destination address, forwards the multicast traffic F1 through the a interface with an Active flag in the multicast route M1, copies a copy of the multicast traffic F1, adds a probe flag to the copied multicast traffic F1 to obtain a probe traffic F2, and forwards the probe traffic F2 through the B interface with a backup int flag in the multicast route M2.
In step S44, the multicast router R1 receives the probe traffic F2, and when the probe flag in the probe traffic F2 is identified, creates a new multicast route M2 according to the probe traffic F2, where the multicast route M2 uses the D interface as the ingress interface, 172.168.0.2 as the source address, and 227.0.0.1 as the destination address.
Step S45, the multicast routing device R1 determines the IP address of the corresponding RP according to the destination address 227.0.0.1 of the probe traffic F2, then searches the unicast route N2 using the IP address of the RP as the destination address in the FIB of the device, sets the outgoing interface C corresponding to the active next hop in the unicast route N2 on the multicast routing device R1 as the outgoing interface in the multicast route M2, and adds a backhaul int mark to the outgoing interface.
The IP address of the corresponding RP determined according to the destination address 227.0.0.1 may be an IP address of the multicast routing device DUT, or an IP address of a lookup back interface on the multicast routing device DUT.
Optionally, the multicast routing device R1 may also add a BackupInt flag to the ingress interface D in the multicast routing M2.
In step S46, the multicast router R1 forwards the probe traffic F2 through the C interface with a backup int flag.
In step S47, the multicast routing device DUT (target rendezvous point 300) receives the probe traffic F2, and when the probe flag in the probe traffic F2 is identified, finds the RPF route corresponding to the source address 172.168.0.2 of the probe traffic F2 and the multicast route M3 corresponding to the destination address 227.0.0.1 of the probe traffic F2.
Step S48, the multicast routing device DUT determines that the interface where the probe traffic F2 actually arrives is an E interface, sets the E interface as an RPF interface in the RPF route, adds a backup RPF mark to the RPF interface (i.e., forms a backup RPF interface), sets the E interface as an ingress interface in the multicast route M3, and adds a backup RPF mark to the ingress interface.
Optionally, the multicast routing device DUT may set the IP address of the C interface as the RPF neighbor corresponding to the backup RPF interface E in the RPF route.
Through the above process, when the multicast router R2 detects R2
When the path of the DUT fails, the multicast traffic can be forwarded through the backup output interface B, so that the multicast traffic is enabled to follow R2
R1
The DUT, which is a backup forwarding path, is forwarded and can be checked by the RPF when forwarded to the DUT, and forwarded to the members of the multicast group, thereby avoiding packet loss due to link failure.
Fig. 6 is a functional block diagram of a multicast network 10 according to an embodiment of the present disclosure. The multicast networking 10 includes a first multicast routing device 100 and a target rendezvous point 300 corresponding to a target multicast group, where the target rendezvous point 300 includes a first receiving module 310 and a first setting module 320.
The first receiving module 310 is configured to receive multicast traffic forwarded by a first multicast routing device through different forwarding paths, and when the received multicast traffic is probe traffic including a probe mark, search, in the target aggregation point 300, for an RPF route corresponding to a source address of the probe traffic and a multicast route corresponding to a destination address of the probe traffic.
In the embodiment of the present disclosure, the description about the first receiving module 310 may refer to the detailed description of step S25 shown in fig. 2, that is, step S25 may be performed by the first receiving module 310.
The first setting module 320 is configured to set, in the found RPF route, an interface, where the target rendezvous point 300 receives the probe traffic, as a backup RPF interface, and set, in the found multicast route, an interface, where the target rendezvous point 300 receives the probe traffic, as a backup ingress interface, so that multicast traffic, where a forwarding path is the same as the probe traffic, can pass RPF inspection at the target rendezvous point.
In the embodiment of the present disclosure, the description about the first setting module 320 may refer to the detailed description of step S26 shown in fig. 2, that is, step S26 may be performed by the first receiving module 310.
Optionally, in this embodiment of the present disclosure, a unicast route and a target multicast route using an IP address of the target multicast group as a destination address are stored in the FIB of each multicast routing device in the multicast networking 10, where the unicast route has a primary next hop and a backup next hop. In this case, the first multicast routing device 100 may include a second setup module 110.
The second setting module 110 is configured to search a unicast route using the IP address of the target rendezvous point 300 as a destination address in a forwarding information table of the first multicast routing device 100, and set an egress interface corresponding to a backup next hop of the searched unicast route as a backup egress interface of the target multicast route, so as to forward, through the backup egress interface, a multicast traffic using the IP address of the target multicast group as the destination address when a failure occurs in an active forwarding path between the first multicast routing device 100 and the target rendezvous point 300.
In the embodiment of the present disclosure, the description about the second setting module 110 may refer to the detailed description of step S21 shown in fig. 2, that is, step S21 may be performed by the second setting module 110.
Optionally, in this embodiment of the present disclosure, the first multicast routing device 100 further includes a sending module 120.
The sending module 120 is configured to, when receiving the multicast traffic sent by the multicast source to the target multicast group, add the detection flag to the multicast traffic to form the detection traffic, and forward the detection traffic through the backup egress interface, so as to establish an optimal forwarding path of the multicast traffic between the first multicast routing device 100 and the target rendezvous point 300 as the backup forwarding path.
In the embodiment of the present disclosure, the description about the sending module 120 may refer to the detailed description of step S22 shown in fig. 2, that is, step S22 may be executed by the sending module 120.
In this embodiment of the present disclosure, the multicast networking 10 further includes a second multicast routing device 200 located on the backup forwarding path, and the second multicast routing device 200 may include a second receiving module 210 and a third setting module 220.
The second receiving module 210 is configured to, when the second multicast routing device 200 receives the probe traffic, search a unicast route using the IP address of the target rendezvous point 300 as a destination address in a forwarding information table of the multicast routing device, and establish a multicast route according to the probe traffic in the forwarding information table of the second multicast routing device 200.
In the embodiment of the present disclosure, the description about the second receiving module 210 may refer to the detailed description of step S23 shown in fig. 2, that is, step S23 may be performed by the second receiving module 210.
The third setting module 220 is configured to set an interface, where the second multicast routing device 200 receives the probe traffic, as a backup ingress interface of the newly-built multicast route, set an egress interface, corresponding to the primary next hop of the found unicast route, as a backup egress interface of the newly-built multicast route, and forward the probe traffic through the backup egress interface.
In the embodiment of the present disclosure, the description about the third setting module 220 may specifically refer to the detailed description of step S24 shown in fig. 2, that is, step S24 may be performed by the third setting module 220.
It should be understood that, in the embodiment of the present disclosure, any multicast routing device in the multicast networking 10 may serve as the first multicast routing device 100, may serve as the target rendezvous point 300 corresponding to the target multicast group, and may also serve as the second multicast routing device 200 located on the backup forwarding path between the first multicast routing device 100 and the target rendezvous point 300, so that the above-mentioned functional modules may operate on different multicast routing devices or may operate on the same multicast routing device at the same time.
To sum up, in the route setting method and the multicast networking provided by the embodiment of the present disclosure, the target rendezvous point receives the multicast traffic forwarded by the first multicast routing device through different forwarding paths, and when the received multicast traffic is the probe traffic including the probe mark, the RPF route corresponding to the source IP address of the probe traffic and the multicast route corresponding to the destination IP address of the probe traffic are searched in the target rendezvous point. And setting an interface of the target rendezvous point receiving the flow as a backup RPF interface in the searched RPF route, and setting an interface of the target rendezvous point receiving the detection flow as a backup interface in the searched multicast route, so that the multicast flow with the same forwarding path as the detection flow can pass the RPF check on the target rendezvous point. Therefore, when the main forwarding path fails, the multicast traffic forwarded from other forwarding paths can be prevented from being discarded because the multicast traffic cannot pass the RPF check.
In the embodiments provided in the present disclosure, it should be understood that the disclosed networking and method may be implemented in other ways. The functional block embodiments of the networking described above are merely illustrative, for example, the flowchart and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of apparatus, methods and computer program products according to various embodiments of the present disclosure. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems which perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.
The foregoing is illustrative of selected embodiments of the present disclosure only and is not intended to be limiting thereof, as numerous modifications and variations will be apparent to those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present disclosure should be included in the protection scope of the present disclosure.
Claims (10)
1. A route setting method is applied to a multicast networking system, the multicast networking system comprises a first multicast routing device and a target convergent point corresponding to a target multicast group, the method comprises the following steps:
the target rendezvous point receives multicast traffic forwarded by the first multicast routing equipment through different paths, and when the received multicast traffic is detection traffic including detection marks, Reverse Path Forwarding (RPF) routing corresponding to a source address of the detection traffic and multicast routing corresponding to a destination address of the detection traffic are searched in the equipment, wherein when the first multicast routing equipment receives the multicast traffic sent to the target multicast group by a multicast source, the detection marks are added into the multicast traffic to form the detection traffic;
setting the interface of the target rendezvous point receiving the detection flow as a backup RPF interface in the searched RPF route, and setting the interface of the target rendezvous point receiving the detection flow as a backup interface in the searched multicast route, so that the multicast flow with the same forwarding path as the detection flow can pass RPF check on the target rendezvous point.
2. The route setting method according to claim 1, wherein a forwarding information table of each multicast routing device in the multicast networking system stores a unicast route and a target multicast route having an active next hop and a backup next hop, the target multicast route having an IP address of the target multicast group as a destination address, and the method further comprises:
the first multicast routing equipment searches a unicast route which takes the IP address of the target rendezvous point as a destination address in a forwarding information table of the equipment, and sets an outgoing interface corresponding to a backup next hop of the searched unicast route as a backup outgoing interface of the target multicast route, so that when a main forwarding path between the first multicast routing equipment and the target rendezvous point fails, multicast flow which takes the IP address of the target multicast group as the destination address is forwarded through the backup outgoing interface.
3. The route setting method according to claim 2, wherein the first multicast routing device searches a forwarding information table of the first multicast routing device for a unicast route using the IP address of the target rendezvous point as a destination IP address, and the method comprises:
the first multicast routing equipment determines the IP address of the target rendezvous point according to the target address of the target multicast routing at intervals of preset time length, and searches a unicast routing taking the IP address of the target rendezvous point as the target IP address in a forwarding information table of the equipment; or
When the first multicast routing equipment receives the multicast traffic sent by the multicast source to the target multicast group, the first multicast routing equipment determines the IP address of the target rendezvous point according to the destination address of the multicast traffic, and searches a unicast route which takes the IP address of the target rendezvous point as the destination address in a forwarding information table of the first multicast routing equipment.
4. A route setup method according to claim 2 or 3, characterized in that the method further comprises:
when finding the unicast route with the IP address of the target rendezvous point as the destination address, the first multicast routing equipment sets the outgoing interface corresponding to the main next hop of the unicast route as the main outgoing interface of the target multicast route.
5. A route setup method according to claim 2 or 3, characterized in that the method further comprises:
and the first multicast routing equipment forwards the detection flow through the backup output interface so as to establish an optimal forwarding path of the multicast flow between the first multicast routing equipment and the target rendezvous point as a backup forwarding path.
6. The routing setup method of claim 5, wherein the multicast networking system further comprises a second multicast routing device located on the backup forwarding path, the method further comprising:
when the second multicast routing equipment receives the detection flow, a unicast route with the IP address of the target convergent point as a destination address is searched in a forwarding information table of the second multicast routing equipment, and a multicast route is newly established in the forwarding information table of the second multicast routing equipment according to the detection flow;
and the second multicast routing equipment sets the interface receiving the detection flow as a backup input interface of the newly-built multicast route, sets the outlet interface corresponding to the main next hop of the searched unicast route as a backup outlet interface of the newly-built multicast route, and forwards the detection flow through the backup outlet interface.
7. A multicast networking system is characterized in that the multicast networking system comprises a first multicast routing device and a target convergent point corresponding to a target multicast group; the target convergence point includes:
a first receiving module, configured to receive multicast traffic forwarded by a first multicast routing device through different forwarding paths, and when the received multicast traffic is probe traffic including a probe mark, search, in the target rendezvous point, for an RPF route corresponding to a source address of the probe traffic and a multicast route corresponding to a destination address of the probe traffic, where, when the first multicast routing device receives multicast traffic sent by a multicast source to the target multicast group, the probe mark is added to the multicast traffic to form the probe traffic;
a first setting module, configured to set, in the found RPF route, an interface at which the target rendezvous point receives the probe traffic as a backup RPF interface, and set, in the found multicast route, an interface at which the target rendezvous point receives the probe traffic as a backup ingress interface, so that multicast traffic having a forwarding path that is the same as the probe traffic can pass RPF inspection at the target rendezvous point.
8. The multicast networking system according to claim 7, wherein a unicast route and a target multicast route having an IP address of the target multicast group as a destination address are stored in the forwarding information table of each multicast routing device in the multicast networking system, and the unicast route has a primary next hop and a backup next hop; the first multicast routing device comprises:
a second setting module, configured to search a unicast route using the IP address of the target rendezvous point as a destination address in a forwarding information table of the first multicast routing device, and set an egress interface corresponding to a backup next hop of the searched unicast route as a backup egress interface of the target multicast route, so as to forward, through the backup egress interface, multicast traffic using the IP address of the target multicast group as the destination address when a failure occurs in a primary forwarding path between the first multicast routing device and the target rendezvous point.
9. The multicast networking system according to claim 8, wherein the first multicast routing device further comprises:
and the sending module is used for forwarding the detection flow through the backup output interface so as to establish an optimal forwarding path of the multicast flow between the first multicast routing equipment and the target rendezvous point as a backup forwarding path.
10. The multicast networking system of claim 9, further comprising a second multicast routing device located on the backup forwarding path, the second multicast routing device comprising:
a second receiving module, configured to, when the second multicast routing device receives the probe traffic, search a unicast route using the IP address of the target rendezvous point as a destination address in a forwarding information table of the multicast routing device, and establish a multicast route in the forwarding information table of the second multicast routing device according to the probe traffic;
and a third setting module, configured to set an interface, where the second multicast routing device receives the probe traffic, as a backup ingress interface of the newly-built multicast route, set an egress interface, corresponding to the primary next hop of the found unicast route, as a backup egress interface of the newly-built multicast route, and forward the probe traffic through the backup egress interface.
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