WO2012001511A1

WO2012001511A1 - A method for determining the routing information among nodes in a communication network and a device thereof

Info

Publication number: WO2012001511A1
Application number: PCT/IB2011/001720
Authority: WO
Inventors: Chunyan Yao; Shuigen Yang; Zheng LIANG
Original assignee: Alcatel Lucent
Priority date: 2010-06-29
Filing date: 2011-06-15
Publication date: 2012-01-05
Also published as: CN102316004A; CN102316004B

Abstract

There is provided a method, in a server of a communication network, for determining routing path among nodes, comprising the steps of: receiving node-identifying information from a client, wherein the node-identifying information is used to identify at least one node; based on the node-identifying information, determining the routing path among the at least one node identified by the node-identifying information in accordance with the topology information of the communication network; and transmitting the routing path among the at least one node to the client. With the method or the device thereof, there would be a one-off provision with the bidirectional routing path information between any two nodes among multiple specified nodes, and the bidirectional routing path information could also be provide to the terminal in a subscription service fashion.

Description

A method for determining the routing information among nodes in a communication network and a device thereof

Field of the Invention

The present invention is pertinent to a communication network, particularly to a method for determining the routing information among nodes in a communication network and a device thereof.

Background of the Invention

Most customers, especially those webmasters, surfing in the Internet are very interested in: by which routing path their hosts or other network nodes connect to the Internet, e.g. how do their ISPs connect to one or more NAPs . By which routing path two interested network nodes in the internet exchanging packets , e.g. webmasters usually are very interested in whether their customers can access to their Website and how fast the packets are delivered in some network paths that they care . And Webmasters can select a suitable ISP for their Website based on the abovementioned information .

Currently, there are many feasible technical means in various forms for implementation of the above functionality, for example, "Traceroute" is a common tool to get known the path from the host which executes "Traceroute" command to any other host in the Internet. In Windows, the command can have an instantiation of "tracert", in Linux, the command can have an instantiation of "tarcepath", and Windows NT-based operating systems also provide "PathPing", which provides similar functionality. Whereas, all the abovementioned tool instantiations detect the unidirectional routing path from the host executing such a tool to the target .

Traceroute works depending on the common router practice of sending an Internet Control Message Protocol ( ICMP) Time Exceeded message back to the sender when TTL expiring occurs. By using small TTL values which might quickly expire, Traceroute causes routers to generate, along a packet's normal delivery path, these ICMP messages which are suitable for identifying the router. Thus, following deficiency occurs unavoidably to Traceroute-like tools.

Firstly, the above tool can merely detect the path in a single direction, namely, in the "To" direction of from host to target, while being incapable of providing a path detection in the "Come" direction of from the target back to the host. By using "Traceroute", one customer can only know the routing path from the host which initials Traceroute command to other targets, while incapable of obtaining routing path from other targets to the host.

Secondly, Traceroute-like tools can only come up with a detection of a routing path between only two nodes. In many practical scenarios, it is necessary to know bidirectional unicast paths among multiple pointed nodes one-off instead of getting each bidirectional paths between any two of the pointed nodes and then patching them up.

Additionally, Traceroute-like tools injects extra traffic to the network and needs the ICMP reply from each router along the routing path, which occupies more network resource.

Summary of the Invention

As for the aforesaid background, bidirectional routing path between any two of the multiple specified network nodes can not be acquired one-off. For such a problem, there is provided a method for determining the routing information among nodes in a communication network and a device thereof.

According to one embodiment of the present invention, there is provided a method, in a server of a communication network, for determining routing path among nodes, comprising the steps of: receiving node-identifying information from a client, wherein the node-identifying information is used to identify at least one node; determining, according to the topology information of the communication network, the routing path among the at least one node identified by the node-identifying information based on the node-identifying information; and transmitting the routing path among the at least one node to the client .

Wherein, the server could take the form of Path Tracing Server, vertical server or the association/combination thereof.

In another embodiment of the present invention, the server may be a Path Tracing Server, and the step of "determining the routing path among the at least one node identified by the node-identifying information" further comprises: acquiring, from a vertical server, the topology information of a first node of the at least one node identified by the node-identifying information according to the node-identifying information; and determining the routing path between the first node and a second node of the at least one node according to the topology information of the first node.

In yet another embodiment of the present invention, the server may be a vertical server, and the step of "determining the routing path among the at least one node identified by the node-identif ing information" further comprises: acquiring, from the topology information, stored locally in the vertical server, of the communication network, the topology information of a first node of the at least one node identified by the node-identifying information based on the node-identifying information; and determining the routing path between the first node and a second node of the at least one node according to the topology information of the first node.

In still another embodiment of the present invention, the communication network further comprises a Path Tracing Server, and the step of "receiving node-identifying information from a client, " further comprises: receiving the node-identifying information, f om the client, forwarded by the Path Tracing Server; and the step of "transmitting the routing path among the at least one node to the client" further comprises: forwarding, via the Path Tracing Server, the routing path among the at least one node to the client".

In those methods according to embodiments of the present invention, the node-identifying information, received from the client, may comprise one or more specified communication nodes, and according to the topology information of the communication network, the routing path between any two of the multiple specified nodes can be determined one-off.

Additionally, the server for performing such a method may be Path

Tracing Server, vertical server or the combination thereof, thus leading to a low functional coupling for the topology of the communication network, and hence a clear functional architecture and a high performance efficiency. Meanwhile, it is less probable for the vertical server to suffer from a network attack to some extent if the above method is performed cooperatively by Path Tracing Server and vertical server.

Furthermore, by the method of present invention, the traffic load information of the routing path can be obtained and sent to the client so as to acquaint the client with other information relevant to the communication of the routing path, not limited to the routing path per se .

Optionally, the node-identifying information in the above embodiments further comprises a subscription periodic value, and the step of "transmitting the routing path among the at least one node to the client" further comprises: transmitting periodically the routing path to the client according to the subscription periodic value.

By transmitting periodically the routing path to the client according to the subscription periodic value in the node-identifying information, those queries of the client for such information can be avoidable, therefore decrease the traffic load of the network.

In another embodiment of the present invention, there is provided a first determining device for determining the routing path among nodes in a communication network, comprising: a first identifying-information receiving unit, for receiving node-identifying information f om a client, wherein the node-identifying information is used to identify at least one node; a first topology information acquiring unit, for acquiring, from a vertical server, the topology information of a first node of the at least one node identified by the node-identifying information according to the node-identifying information; a first routing-path determining unit, for determining the routing path between the first node and a second node of the at least one node according to the topology information of the first node; and a first routing-path information transmitting unit, for transmitting the routing path among the at least one node to the client.

In another embodiment of the present invention, there is provided a second determining device for determining the routing path among nodes in a communication network, comprising: a second identifying-information receiving unit, for receiving node-identifying information from a client, wherein the node-identif ing information is used to identify at least one node; a second topology information acquiring unit, for acquiring, from the topology information, stored locally in the vertical server, of the communication network, the topology information of a first node of the at least one node identified by the node-identifying information based on the node-identifying information; a second routing-path determining unit, for determining the routing path between the first node and a second node of the at least one node according to the topology information of the first node; and a second routing-path information transmitting unit, for transmitting the routing path among the at least one node to the client.

Brief Description of the Drawings

Features, aspects and advantages of the present invention will become more obvious by reading the following description of non-limiting embodiments with the aid of appended drawings.

Fig.1 illustrates the topology of an embodiment of a communication network system including a client and a server;

Fig. 2 illustrates the flow chart of an embodiment of method for determining routing path among nodes in a server of the communication network;

Fig. 3 illustrates the flow chart of another embodiment of method for determining routing path among nodes in a server of the communication network;

Fig. 4 illustrates the flow chart of yet another embodiment of method for determining routing path among nodes in a server of the communication network;

Fig. 5 illustrates the functional block diagram of an embodiment of a first determining device for determining routing path among nodes in a communication network;

Fig. 6 illustrates the functional block diagram of another embodiment of a second determining device for determining routing path among nodes in a communication network;

Fig. 7 illustrates the flow chart of still another embodiment of method for determining routing path among nodes in a server of the communication network;

wherein, same or similar reference numerals refer to the same or similar device (module ) or step of method.

Detailed description of embodiments

Some customers are usually in need of a subscription service of the routing path status among the nodes in a communication network. Moreover, some customers always need to pay attention to the routing path and traffic load of those concerned nodes or other information relevant to the routing path. Such a service requirement resembles Really Simple Syndication (RSS), which can be referred to as path status subscription. By means of this service, terminal user could have a subscription of routing path and traffic load, and other status relative to such a routing path. And operator could become more competitive with such a service. Operator might transmit, periodically or at the time the subscription information changes, the subscription information to the client, which could increase the traffic flow and enhance the added value of the product. Therefore, there is a need for a routing-path detecting tool in the communication network to provide bidi ectional routing path among multiple nodes in one-off manner and the information relative thereto. Furthermore, it would be advantageous for such a tool to be capable of supporting the subscription service of routing-path status.

Detailed description is exemplarily made for the embodiments of the present invention in combination with the accompanying drawings.

Fig.l illustrates the topology of an embodiment of communication network system including a client and a server, wherein client 20 sends the node-identif ing information to the server 10. For example but not limited to, server 10 may take the form of a Path Tracing Server 11 or vertical server 12 or the combination thereof. Certainly, those skilled in the art can readily appreciate that , for some scenarios, the vertical server 12 therein could be replaced by a SN P server.

Additionally, the communication network is configured with communication nodes of A, B, C, D, and several routers: routerl, router2, router3, router4, router5, although not shown in Figures.

Fig. 2 illustrates the flow chart of an embodiment of method for determining routing path among nodes in a server of the communication network. The method of determining routing path among nodes comprises a identi fying-information receiving step Sll, a routing-path determining step S12 and a routing-path information transmitting step S13.

In the step Sll, server 10 receives a node-identifying information from a client 20, wherein the node-identifying information is used to identify at least one node.

For example, a customer identifies, by client 20, the communication nodes A, B and C in term of domain name, and client 20 may transmit the information, identifying the communication node A, B and C, to server 10 in a form of Path query message. Server 10 receives the Path query message from client 20, wherein the node-identifying information in the Path query message is used to identify communication node A, communication node B, communication node C, with the routing path thereamong to be determined.

In the step S12, server 10 determines, according to the topology information of the communication network, the routing path among the at least one node identified by the node-identifying information based on the aforesaid node-identifying information. Based on the node-identifying information for communication node

A, B, C, server 10 determines the routing path among communication node A, B, C according to the connection topology information among the communication node A, B, C in communication network. For example, routing path between node A and B is exemplarily determined as "A router2 router3 router5 B", and routing path between node

B, C is exemplarily determined as "B -> router5 routerl -> C". Preferably, server 10 determines all possible routing path among the communication node A, B, C, namely, "A - B, B -> A, A -> C, C -> A, C B, B -> C".

In step S13, server 10 transmits the routing path among the at least one node to the client.

For instance, the routing path from communication node A to B is determined in step S12 as "A -> router2 -> router3 -> router5 B" and the routing path from communication node B to A as "B -> router5 router3 routerl A", likewise, determination of routing path resulting from step S12 may comprise the routing path between "communication node A and C" and "communication node B and C" . Then preferably, server 10 may provide, in term of Path Reply message, client 20 with the above determined routing path information between any two of the all the existing communication nodes among communication node A, B and C. Herein, those skilled in the art should appreciate: the Path Reply message may be split and encapsulated into several datum packets for being sent to client 20 if Path Reply message is too large in size to be encapsulated a single datum packet.

Fig. 3 illustrates the flow chart of another embodiment of method for determining routing path among nodes in a server of the communication network, wherein server 10 is a Path Tracing Server 11. As shown in Fig. 3, routing-path determining step in the corresponding embodiments as indicated by Fig.2 comprises two sub-steps S121 and S122.

In step S121, Path Tracing Server 11 acquires, from a vertical server 12, the topology information of a first node of the at least one node identified by the node-identifying information according to the node-identifying information.

In the above embodiment, node-identifying information identifies network nodes A, B, C, then Path Tracing Server 11 may acquires, from vertical server 12, the topology information of the specified network node(s), for example node A.

In step S122, Path Tracing Server 11 determines the routing path between the first node and a second node, for instance node B, of the specified at least one node according to the topology information of the node A. Namely, according to the topology information of network node A resulting from step S121, Path Tracing Server 11 determines the routing path from network node A to network node B, for example, the routing path is determined as "A -> router2 router3 router5 B".

Fig. 4 illustrates the flow chart of yet another embodiment of method for determining routing path among nodes in a server of the communication network, wherein server 10 takes the form of a vertical server 12, and in such an embodiment, as shown in Fig. , routing-path determining step in the embodiment corresponding to Fig .2 further comprises step S121' and S122'.

In step Sll, vertical server 12 may directly receive the node-identifying information from client 20, and such node-identifying information is used to identify at least one node, for example communication node A, B, C.

In step S121', vertical server 12 acquires, from the topology information, stored locally in vertical server 12, of the communication network, the topology information of a first node of the at least one node identified by the above node-identifying information based on the node-identifying information. In this embodiment, the node-identifying information specifies network node A, B, C, then vertical server 12 may acquire natively the topology information of the specified network node(s), for example network node A.

In step S122', determines the routing path between the first node and a second node, for example network node B, of the at least one node according to the topology information of the first node. Namely, according to the topology information of network node A resulting from step S121' , the routing-path from network node A to network node B is determined exemplarily as "A -> router2 router3 router5 -> B".

Fig. 7 illustrates the flow chart of still another embodiment of method for determining routing path among nodes in a server of the communication network. Optionally, in this embodiment, the communication network further comprises a Path Tracing Server 11, as shown in Fig.7, first, client 20 may provide , in term of Path query message, Path Tracing Server 11 with the identifying information of at least one node (s) , for example communication node A, B, C. Path Tracing Server 11 receives the node-identifying information from client 20, and the node-identifying information is used to identify communication node A, B, C.

Subsequently in step Sll', vertical server 12 receives the node-identifying information specifying the node A, B, C, which is initially sent by the client 20, forwarded by the Path Tracing Server 11. Upon completion of step S121' and S122', in step S13', vertical server 12 forwards, via Path Tracing Server 11, the routing path among at least one node to client. Then, in response to the instruction from vertical server 12, Path Tracing Server 11 forwards routing path among at least one node to client 20. For example, it is feasible to provide, in term of Path Reply message, Path Tracing Server 11 with all existing routing paths of A -> B, B -> A, A - C, C - A, C -> B, B -> C among the above communication node A, B, C, and to instruct Path Tracing Server 11 to forward the routing path information to client 20. Subsequently, Path Tracing Server 11 transmits the routing paths among above communication node A, B, C to client 20, wherein routing path may vary with different communication network status, and in this embodiment, the routing path of A -> B is exemplarily A -> router2 router3 -> router5 B.

Optionally, in another embodiment, server 10 further acquires the traffic load information of the routing path, and transmits such traffic load information to client 20, wherein, traffic load information includes but not limited to such information for reflecting the traffic load status as data throughput, transmission delay, bandwidth, packet loss rate . Specifically, the above-mentioned traffic load information can be derived from, for example metric information in the routing table attribute in Forwarding Information Base of communication network for this embodiment. Those skilled in the art can readily appreciate that, in the above transmitting step, after Path Tracing Server 11 acquires the traffic load information of the routing path, for example the routing path of ft router2 router3 router5 B from A to B, it may directly transmit the traffic load information of such a routing path to client 20, or otherwise, vertical server 12 may forward, via Path Tracing Server 11, such traffic load information to client 20 upon the acquisition of the traffic load information of routing path of from A to B.

Optionally, in another embodiment, first, client 20 may provide, in term of Path query message, Path Tracing Server 11 with the identifying information of at least one node, such as communication

5 node A, B, C, and information of subscription periodic value.

Correspondingly, the method of this embodiment further comprises a step that server 10, which may be Path Tracing Server 11 or vertical server 12, transmits periodically the routing path to the client 20 according to the subscription periodic value. For example,

0 node-identifying information received in step Sll further comprises, besides the identifying information for communication node of "A, B, C", a subscription periodic value of 5s applicable for nodes A, B, C. Accordingly, Path Tracing Server 11 transmit, in a cycle of 5s, to client 20 with the routing path information among above

5 communication node A, B, C, such that such routing path information keep a continuous update for client 20. Or else, vertical server 12 may transmit, by forwarding via Path Tracing Server 11, to client 20 with the above updated routing path information among communication node A, B, C in a cycle of 5s.

D Optionally, in another embodiment of the present invention, first, client 20 transmits, in term of Path query message, to Path Tracing Server 11 with the identifying information of at least one node, such as communication node A, B, C, and an real-time updating indicator, wherein the real-time updating indicator is used to instruct server

> 10 to transmit, in real time fashion, the updated routing path information to client 20 when it detects that the routing path status among communication node A, B, C changes. Correspondingly, the method of this embodiment further comprises the step that server 10, which may be Path Tracing Server 11 or vertical server 12, transmits, in real-time manner, the updated routing path among the at least one node to the client 20 if it is detected that the routing path among the at least one node changes. For example, the node-identif ing information, received in the step Sll, comprises, besides the identifying information for communication node of "A, B, C", a real-time updating indicator applicable for nodes A, B, C, then Path Tracing Server 11 keeps in state of real-time monitor and computation for the routing path among node A, B, C, and transmits, in real time fashion, the updated routing path information among node A, B, C to client 20 when it is detected that the routing path status among node A, B, C varies, such that such routing path information has a continuous update on client 20. Otherwise, vertical server 12 may transmit, by forwarding via Path Tracing Server 11, to client 20 with the above updated routing path information among communication node A, B, C in real-time manner.

Herein, those skilled in the art can readily appreciate that: in embodiments of the present invention, node-identifying information for identifying at least one node comprises any one of the network access identifier for the at least one node, the domain name, or IP address, as well as the combination thereof, the specific form to represent the identifying information of the communication node does not introduce any limit into the present invention. For example, in this embodiment, the identifying information for communication node A, B, C may comprise the IP address 162.105.74.55 of communication node A and the website "www.sina.com.cn" of communication node B and the network access indicator of communication node C.

In another embodiment of the present invention, through client 20, a customer identifies, in term of domain name, the communication node A, then client 20 would provide, in term of Path query message, server 10 with the identifying information of communication node A and the local host for client 20. Correspondingly, the node-identifying information received in step 311 comprises the identifying information for communication node A and the local host for client 20. Herein, in step S12, base on such node-identif ing information, Path Tracing Server 11 or vertical server 12 acquires the routing path between node A identified by the above node-identifying information and the local host for client 20 according to the topology information of communication network, namely, the routing path of local host for client 20 -> A and/or A -> the local host for client 20, which may exemplarily be host -> routerl -> router2 -> A, A -> router2 -> routerl - host.

The topology information in the above embodiments may comprise exemplarily Forwarding Information Base, and correspondingly, step S12 may further comprise the step of acquiring, by Longest-prefix matching, the routing path among the at least one node identified by the node-identifying information, based on the node-identifying information according to the Forwarding Information Base of the communication network.

Surely, those skilled in the art can readily appreciate that, the above topology information is not limited to the Forwarding Information Base, and may further comprise the link status or the port status of at least one node, such as communication node A, B, C, or else those information beneficial to determine communication status of the routing path, such as the relation of distance or adjacency of communication node A, B, C.

For example, in this embodiment, the node-identif ing information identifies communication node A, B, C, then first, according to the acquired unicast FIB of the node A, Longest-prefix matching is conducted between IP unicast address of another network node , such as node B, and the prefix of FIB of communication node A. If no presence of any matched FIB entry, then no routing path exists from A to B. This failure information might be recorded and conduct is terminated.

5 Subsequently, it is the turn to determine the routing path from B to A. If the Longest-prefix matching could come up with a matched FIB entry, such as entry2, then "next hop router" in the matched entry indicates the next hop router, such as router2. Meanwhile, IP address of router2 is recorded.

0 Subsequently, after acquisition of the FIB of router2,

Longest-prefix matching is conducted between IP unicast address of node B and the prefix of FIB of router2. If no presence of any matched FIB entry, then no routing path exists from router2 to node B. This failure information might be recorded and matching is terminated.

5 If with a presence of any matched FIB entry, such as entry3, then record the IP address of the "next hop router" identified by entry3. The "next hop router" in such a matched entry is obtained, and the above Longest-prefix matching is repeated between the "next hop router" and node B until the "next hop router" in the finally gained

) entry points to communication node B itself.

Certainly, of all the specified nodes, routing path information of any two nodes, namely A -> B, B -> A, A -> C, C A, C -> B, B -> C herein, could be obtained by the above steps, wherein Longest-prefix matching will not be described in any detail in the interest of the

! avoidance of redundancy.

In another embodiment of the present invention, the network topology information comprise a FIB, then herein, in step S121, according to the node-identifying information, Path Tracing Server 11 acquires, from vertical server 12, the Forwarding Information Base of a first node, such as node A, of the at least one node (e.g. node A, B, C ) identified by the node-identifying information . Subsequently, in step S122, according to the Forwarding Information Base of the first node, Path Tracing Server 11 determine, by means of Longest-prefix matching, the routing path from the node A to a second node, e.g. node B, of the at least one node, and no detail herein for avoidance of redundancy.

In still another embodiment of the present invention, the network topology information comprise a FIB, then herein, in step S121' , based on the node-identifying information, vertical server 12 acquires, from the communication network FIB stored locally in vertical server 12 per se, the FIB of a first node, such as node A, of the at least one node (e.g. node A, B, C) identified by the node-identifying information. Subsequently, in step S122', according to FIB of node A, to determine, by means of Longest-prefix matching, the routing path from the node A to a second node, e.g. node B, of the at least one node, and no detail herein for avoidance of redundancy.

Fig. 5 illustrates the functional block diagram of an embodiment of a first determining device for determining routing path among nodes in a communication network. As shown in this figure, the first determining device 100 comprises: a first identifying-information receiving unit 101, a first topology information acquiring unit 102, a first routing-path determining unit 103, a first routing-path information transmitting unit 104.

The first determining device 100 usually may be configured in a

Path Tracing Server 11, wherein the first identifying-information receiving unit 101 is configured to receive node-identifying information from client 20, wherein the node-identifying information is used to identify at least one node, for instance, the node-identifying information may identify node A, B, C. The first topology information acquiring unit 102 is configured to acquire, from a vertical server 12, the topology information of a first node, such as node A, of the at least one node identified by the node-identifying information according to the node-identifying information. The first routing-path determining unit 103 is configured to determine the routing path between the node A and a second node, such as node B, of the at least one node according to the topology information of node A. Preferably, the first routing-path determining unit 103 determines the routing path between any two of the communication node A, B, C, e.g., A -> B, B -> A, A -> C, C A, C -> B, and B -> C. The first routing-path information transmitting unit 104 is configured to transmit the routing path among the at least one node to the client 20, wherein the routing path comprises any one or more of the following item: A -> B, B -> A, A -> C, C -> A, C B, B -> C. Preferably, the routing path comprises all the above routing paths among the at least one node, namely, A - B, B -> A, A -> C, C -> A, C ^- B and B -> C.

In another embodiment of the present invention, the topology information comprises Forwarding Information Base, correspondingly, the first topology information acquiring unit 102 therein further comprises a first FIB acquiring unit (not shown in the Figure) , the first routing path determining unit 103 further comprises a first Longest-prefix matching unit (not shown in the Figure) .

In the above embodiment, the first FIB acquiring unit is configured to acquire, from vertical server, the Forwarding Information Base of a first node of the at least one node identified by node-identifying information according to the node-identifying information. For example, the node-identif ing information specifies the node A, B, C, the first FIB acquiring unit acquires, from the vertical server 12, the Forwarding Information Base of node A according to the node-identifying information. The first Longest-prefix matching unit is configured to determine, by means of Longest-prefix matching, the

5 routing path from the first node to a second node of the at least one node according to the Forwarding Information Base of the node. In this embodiment, The first Longest-prefix matching unit determine, by means of Longest-prefix matching, the routing path from the node ft to a second node B according to the Forwarding Information Base

~) of the node A, for example, the determined routing path might be A - router2 -> router3 router5 -> B. Likewise, first FIB acquiring unit may also cooperate with the first Longest-prefix matching unit to determine other routing path among communication node A, B, C, such as B -> A, A -> C, C -> A, C -> B, B -» C.

j Fig. 6 illustrates the functional block diagram of another embodiment of a second determining device for determining routing path among nodes in a communication network. As shown in this figure, the second determining device 200 comprises: a second identifying-information receiving unit 201, a second topology information acquiring unit 202, a second routing-path determining unit 203, a second routing-path information transmitting unit 204.

The second determining device 200 usually may be configured in a vertical Server 12, wherein the second identifying-information receiving unit 201 is configured to receive node-identifying information from client 20, wherein the node-identifying information is used to identify at least one node, for instance, node A, B, C. The second topology information acquiring unit 202 is configured to acquire, from the network topology information stored in its local host of vertical server 12, the topology information of a first node, such as node A, of the at least one node identified by the node-identif ing information based on the above node-identifying information. The second routing-path determining unit 203 is configured to determine the routing path between the node A and a second node, such as node B, of the at least one node according to the topology information of the first node of A. Preferably, The second routing-path determining unit 203 determines the routing path between any two of the communication node A, B, C, e.g., A -> B, B -> A, A C, C -> A, C B, and B -> C . The second routing-path information transmitting unit 204 is configured to transmit the routing path among the at least one node to the client 20, wherein the routing path comprises any one or more of the following item: A B, B A, A -> C, C -> A, C -> B, B -> C . Preferably, the routing path comprises all the above routing paths among the at least one node, namely, A -> B, B -» A, A -> C, C A, C -» B and B -» C.

In another embodiment of the present invention, the topology information comprises Forwarding Information Base, cor espondingly, the second topology information acquiring unit 202 therein further comprises a second FIB acquiring unit (not shown in the Figure) , the second routing path determining unit 203 further comprises a second Longest-prefix matching unit (not shown in the Figure).

In the above embodiment, the second FIB acquiring unit is configured to acguire, from the communication network FIB stored in its local host of vertical server, the Forwarding Information Base of a first node of the at least one node identified by the node-identifying information according to the node-identifying information. For example, the node-identifying information specifies the node A, B, C, the first FIB acquiring unit acquires, from the vertical server 12 in which the second FIB acquiring unit is deployed, the Forwarding Information Base of node A according to the node-identifying information. The second Longest-prefix matching unit is configured to determine, by means of Longest-prefix matching, the routing path from the first node to a second node of the at least one node according to the Forwarding Information Base of the node. In this embodiment, the second Longest-prefix matching unit determine, by means of Longest-prefix matching, the routing path from the node A to a second node B according to the Forwarding Information Base of the node A, for example, the determined routing path might be A router2 -> router3 router5 -> B. Likewise, second FIB acquiring unit may also cooperate with the second Longest-prefix matching unit to determine other routing path among communication node A, B, C, such as B -> A, A -> C, C -> A, C -> B, B -> C .

Those skilled in the art could readily appreciate, the device in the present invention can be implemented by means of either hardware module, functional module of software, or the hardware module with functional module of software incorporated therein.

Those skilled in the art could readily appreciate, the above embodiment are intended to be exemplary but not limited thereto. Different technical feature in various embodiments can be combined, so as to gain some technical effect. After examining the accompanying figures, specification and claims, those skilled in the art should readily appreciate and carry out some variation for the above disclosed embodiments. In the claims, the term of "comprise" does not exclude the existence of other device (s) or step(s); indefinite article "a/an" does not exclude the "multiple" case; term of "a first", "a second" is just used for give a name rather than for representing some particular order. Figure number (s) in the claims, if any, should not be construed to be any restriction to protection scope. Multiple component func ionalities in the claim (s) may be implemented by means of an singular hardware or software. The occurrence of some technical features in different dependent claims does not eliminate the possibility of the technical effect resulting from the combination of these technical features.

Claims

What is claimed is:

1. A method, in a server of a communication network, for determining routing path among nodes, the method comprising the steps of:

A. receiving node-identifying information from a client, said 5 node-identifying information being used to identify at least one node;

B. determining, according to the topology of said communication network, the routing path among said at least one node identified by said node-identifying information based on said node-identifying information;

0 C. transmitting said routing path among said at least one node to said client.

2. A method as claimed in claim 1, characterized in that, said server is a path tracing server, said step B further comprising:

Bl. acquiring, from a vertical server according to said 5 node-identifying information, the topology information of a first node of said at least one node identified by said node-identif ing information;

B2. determining the routing path between said first node and a second node of said at least one node according to said topology information ) of said first node.

3. A method as claimed in claim 1, characterized in that, said server is a vertical server, said step B further comprising:

Bl' . acquiring, from the topology information, stored locally in said vertical server, of said communication network, the topology information

1 of a first node of said at least one node identified by said node-identifying information based on said node-identifying information;

B2' . determining the routing path between said first node and a second node of said at least one node according to said topology information of said first node.

4. A method as claimed in claim 3, characterized in that, said communication network further comprises a path tracing server, and said step A further comprises:

5 receiving, via said path tracing server, said node-identifying information from said client;

said step C further comprises:

forwarding, via said path tracing server, the routing path among said at least one node to said client.

0 5. A method as claimed in claim 1, characterized in that, said method further comprises:

D. acquiring the traffic load information of said routing path; and

E. transmitting said traffic load information to said client.

6. A method as claimed in claim 1, characterized in that, said 5 node-identifying information further comprises a subscription periodic value, and said step C further comprises:

transmitting periodically said routing path to said client according to said subscription periodic value.

7. A method as claimed in claim 1, characterized in that, said ) node-identifying information further comprises a real-time updating indicator, and said step C further comprises:

transmitting, in real-time manner, the updated routing path among said at least one node to said client if the routing path among said at least one node changes.

1 8. A method as claimed in claim 1, characterized in that, said node-identifying information for identifying at least one node comprises the network access identifier, or the domain name, or the IP address of said at least one node.

9. A method as claimed in claim 1, characterized in that, if said at least one node comprises only one node, then said step B comprises: acquiring, based on said node-identifying information, the routing path between said one node identified by said node-identifying information and the native host of said client according to the topology information of said communication network.

10. A method as claimed in claim 1, characterized in that, said topology information comprises a forwarding information base, and said step B comprises:

acquiring, by longest-prefix matching, the routing path among said at least one node identified by said node-identif ing information, based on said node-identifying information according to said forwarding information base of said communication network.

11. A method as claimed in claim 2, characterized in that, said topology information comprises a forwarding information base, and said step Bl comprises:

acquiring, from a vertical server, forwarding information base of said first node of said at least one node identified by said node-identifying information according to said node-identifying information

said step B2 comprises:

determining, by longest-prefix matching, the routing path between said first node and said second node of said at least one node according to said forwarding information base of said first node.

12. A method as claimed in claim 3, characterized in that, said topology information comprises a forwarding information base, and said step Bl' comprises:

acquiring, from said forwarding information base, stored locally in said vertical server, of said communication network, said forwarding information base of said first node of said at least one node identified by said node-identifying information base on said node-identifying information;

said step B2' comprises, determining, by longest-prefix matching, the routing path between said first node and said second node of said at least one node according to said forwarding information base of said first node.

13. A method as claimed in any of claims 10-12, characterized in that , said topology information further comprises any one or more of the following items:

- the link status of said at least one node;

- the port status of said at least one node;

- the relation of distance or adjacency of said at least one node.

14. A first determining device for determining the routing path among nodes in a communication network, the first determining device comprising :

a first identif ing-information receiving unit, for receiving node-identifying information from a client, said node-identifying information being used to identify at least one node;

a first topology information acquiring unit, for acquiring, from a vertical server, the topology information of a first node of said at least one node identified by said node-identifying information according to said node-identifying information;

a first routing-path determining unit, for determining the routing path between said first node and a second node of said at least one node according to said topology information of said first node;

a first routing-path information transmitting unit, for transmitting said routing path among said at least one node to said client.

15. A second determining device for determining the routing path among nodes in a communication network, comprising: a second identifying-information receiving unit, for receiving node-identifying information from a client, said node-identifying information being used to identify at least one node;

a second topology information acquiring unit, for acquiring, from the topology information, stored locally in said vertical server, of said communication network, the topology information of a first node of said at least one node identified by said node-identifying information based on said node-identifying information;

a second routing-path determining unit, for determining the routing path between said first node and a second node of said at least one node according to said topology information of said first node;

a second routing-path information transmitting unit, for transmitting said routing path among said at least one node to said client .