CN101547139B - Method and device for announcing network topology changes - Google Patents

Abstract

The embodiment of the invention discloses a network topology change notification method and device, which can quickly notify the network topology change information to the whole network, and improve the network convergence speed. The method includes: when the network topology changes, collecting node router information in the network that needs to be notified and generating a topology change notification list; obtaining a link state message containing network topology change information; encapsulating the topology change notification message with the road status message; sending the encapsulated topology change notification message to the node routers in the topology change notification list. At the same time, the invention also provides a topology change notification device. In the embodiment of the present invention, the topology change notification message is sent in unicast mode through the above method and device, which can quickly notify the network topology change information to the whole network and improve the network convergence speed.

Description

Method and device for notifying network topology changes

technical field

The invention relates to the field of network topology, in particular to a method and device for notifying network topology changes. the

Background technique

With the enrichment of network services, the requirements for network bandwidth increase rapidly, prompting the network deployment to expand in depth in a tree-like manner, and the network capacity expansion trend of provinces, cities, autonomous regions, and counties is obvious. the

Due to the limitation of terminal device deployment, the capacity of routers in the Interior Gateway Protocol (IGP) domain increases significantly, and the convergence speed caused by network topology changes is too slow. the

Figure 1 is a network topology diagram of the prior art, as shown in Figure 1, when the link between router 2 and router 3 changes, if router 1 wants to perceive it, it must pass through all the internal gateways of routers adjacent to router 2 After analyzing the protocol layer, forward it to the router adjacent to the router, and notify the network topology change until the packet is transmitted to router 1. Router 1 performs route calculation according to the topology change, and selects a path that can reach or pass through the destination router 3, thus reducing the convergence speed, so that the convergence of router 1 is recorded in seconds. the

The prior art solution one improves the routing calculation speed of the local machine by improving the routing calculation algorithm, so as to meet the requirement of increasing the convergence speed. The first prior art solution is a technical solution that combines incremental routing calculation (I-SPF), partial routing calculation (PRC) and routing priority convergence technology. the

Incremental routing calculation only calculates a part of the changed routes each time, instead of recalculating all routes. The International Organization for Standardization (ISO) 10589 defines the use of the shortest path (Dijkstra) algorithm for routing calculations. When a node in the network topology changes, this algorithm needs to recalculate all nodes in the network, which takes a long time and takes up too much time. Too many central processing unit (CPU) resources affect the convergence speed of the entire network. Incremental routing calculation improves this algorithm, except that all nodes need to be calculated in the first calculation, and only the nodes affected by the change are calculated each time, and the final generated shortest path tree (Shortest Path Tree, SPT) is the same as the original algorithm The calculated results are the same, which greatly reduces the calculation amount and improves the network convergence speed. the

The principle of partial route calculation is the same as that of incremental route calculation, which only calculates the changed part. However, the partial route calculation does not need to calculate the node path, but updates the leaves according to the shortest path tree calculated by the partial route calculation. In route computation, leaves represent routes, and nodes represent routers. If the shortest path tree after the incremental routing calculation is changed, the partial routing calculation only processes all the leaves on the changed node; if the shortest path tree after the incremental routing calculation does not change, the partial routing calculation only processes the change leaf information. For example, if a node uses an intermediate system to intermediate system (IS-IS) interface, the shortest path tree of the entire network topology remains unchanged. At this time, the partial route calculation only updates the interface route of this node, thereby saving CPU usage. The combination of partial routing calculation and incremental routing calculation can further improve the convergence performance of the network. It is an improvement of the original SPF algorithm, so it has replaced the original algorithm. the

The route-by-priority convergence technology calculates routes with higher priorities first, so that networks with higher priorities converge first. Today, as network resources are increasingly prosperous, the number of routes on core routers has increased significantly, counting as 100,000 routes, including key routes on which tunnel protocols such as Multi-Protocol Label Switching (MPLS) rely to establish paths. In this network, when When the topology changes, the priority calculation of the route of the critical path will reduce the traffic loss caused by the topology change. the

However, when the network topology changes, the convergence time depends on the change notification time and route calculation time. With the increase of CPU calculation speed, the route calculation time is recorded in milliseconds, but the change notification time is recorded in seconds. It improves the routing calculation speed of the local machine, but it does not solve the large amount of time spent in network transmission of change notifications, so the convergence speed is still very slow. the

In the existing technical solution 2, in order to speed up the convergence speed of the entire network, when the intermediate system to intermediate system (IS-IS) receives the link state message (LSP) sent by other routers, if the message is more than The original request for comments (RFC) protocol stipulates that a timer is used to regularly diffuse the link state messages in the link state database, making the synchronization of the link state database (LSDB) relatively slow . The link state fast diffusion feature improves this method. When a router configured with this feature receives one or more relatively new link state packets, it will first diffuse the link state packets that are less than the specified number before route calculation. Go out and speed up the synchronization process of the link state database. This method can greatly improve the convergence speed of the entire network. the

In the existing technical solutions, it is still necessary to use multicast protocol packets to be transmitted in a single hop in the network, that is to say, it needs to be transmitted from the neighbor closest to the changed link to the next neighbor farther away, and spread to the entire network in turn , after the CPU of each router parses and processes the link state, and then starts the timer to send the message, even if it is considered to forward the message before the route calculation, it will take a lot of time during the period, making the convergence speed too slow . the

Contents of the invention

The purpose of the embodiment of the present invention is to provide a network topology change notification method and device, which can quickly notify the network topology change information to the whole network and improve the convergence speed. the

An embodiment of the present invention provides a notification method for network topology changes, including:

When the network topology changes, the node router information that needs to be notified in the network is collected, and a topology change notification list is generated, and the notification list is an Internet Protocol address list of the node router on the shortest path first tree of the topology change initiation router;

Obtain link state packets containing network topology change information;

Encapsulate the topology change notification message according to the obtained link state message containing the network topology change information;

Sending the encapsulated topology change notification message to the node routers in the topology change notification list;

Before the collection of node router information that needs to be advertised in the network, it also includes establishing a fast-advertising router virtual adjacency relationship. the

At the same time, the embodiment of the present invention also provides a device, including:

The processing module is used to collect the node router information that needs to be notified in the network, and generate a topology change notification list, and the notification list is the Internet protocol address list of the node router on the shortest path first tree of the topology change initiation router;

The obtaining module is used to obtain link state messages containing network topology change information;

An encapsulation module, configured to encapsulate a topology change notification message according to the acquired link state message containing network topology change information;

A sending module, configured to send the encapsulated topology change notification message to the node routers in the topology change notification list;

The router virtual adjacency establishing module is used for establishing the fast advertisement router virtual adjacency. the

By introducing the above-mentioned method and device, the embodiment of the present invention can quickly notify the network topology change information to the whole network through the unicast topology change notification message, thereby improving the convergence speed. the

The technical solutions of the embodiments of the present invention will be described in further detail below with reference to the drawings and embodiments. the

Description of drawings

Fig. 1 is the network topology structure figure of prior art;

Fig. 2 is the flow chart of embodiment one of the notification method of network topology change of the present invention;

Fig. 3 is the flow chart of embodiment two of the notification method of network topology change of the present invention;

Fig. 4 is a schematic structural diagram of Embodiment 1 of a notification device for network topology changes in the present invention;

FIG. 5 is a schematic structural diagram of Embodiment 2 of an apparatus for notifying network topology changes according to the present invention. the

Detailed ways

The rapid convergence technology that has been promoted at present focuses on: first, improve the routing calculation algorithm, and increase the calculation speed by reducing unnecessary calculations, such as incremental routing calculation technology, partial routing calculation technology, routing priority convergence technology, the next Hop separation technology, etc.; second, give priority to the diffusion of updated link status messages; third, use intelligent timers to quickly respond to network changes and avoid network oscillations. the

Embodiment 1 of a notification method for network topology changes

Fig. 2 is a flow chart of Embodiment 1 of the notification method for network topology changes in the present invention. As shown in Fig. 2, if the link between router 2 and its adjacent router 3 in the network shown in Fig. 1 changes, then There are the following operations:

Step 11: Collect the node router information that needs to be notified in the network, and generate a topology change notification list; wherein, the node router information is the Internet Protocol (IP) address of the node router, and the topology change notification list is the shortest path first of the topology change starting router The Internet protocol address list of the node router on the tree, the topology change initiation router can also be called the topology change router, router 2 is the topology change initiation router in the embodiment of the present invention, and it is responsible for rapidly notifying the change to the whole network. the

Step 12: Obtain the link state message containing the network topology change information;

Step 13: Encapsulate the topology change notification message according to the obtained link state message containing the network topology change information; wherein, the topology change notification message is a unicast IP message, and router 2 can directly transmit the topology change notification message through unicast mode. The advertisement message is sent to each destination router in the topology change advertisement list. The above process is specifically: if the destination router in the topology change notification list is adjacent to router 2, then router 2 sends the topology change notification message to the protocol message processing unit of the destination router, and the CPU of the destination router processes the message. Parsing and processing to obtain topology change information; if the destination router in the topology change notification list is not adjacent to router 2, router 2 sends the topology change notification message to the forwarding unit of the next router adjacent to router 2, and this router It does not analyze and process the message, but directly forwards the topology change notification message to the forwarding unit of the next adjacent router until the destination router in the topology change notification list receives the topology change notification message, because the Each router forwards the packet directly without parsing and processing it, so the destination router in the topology change notification list thinks that the topology change notification packet is directly sent by router 2, and adopts the above process to shorten the transmission time of the topology change notification packet on the network. time of transmission. the

The topology change announcement message is an IP message, and its source IP address is the interface IP address of the topology change initiation router, i.e. the IP address of router 2, and the destination IP address is the interface IP address of each node router in the topology change announcement list. The topology change notification message carries the link state message containing the network topology change information. The link state message containing the network topology change information is an open shortest path first link state broadcast or an intermediate system to intermediate system link state message. The open shortest path first link state broadcast or intermediate system to intermediate system link state message contains the adjacency relationship between router 2 and router 3, which is the specific content that needs to be notified. The Open Shortest Path First (OSPF) Link State Broadcast (LSA) uses the original IP protocol number, and the Intermediate System to Intermediate System (IS-IS) Link State Packet (LSP) needs to define a new IP protocol number to support The notification method of the network topology change. the

Step 14: Send the encapsulated topology change notification message to the node routers in the topology change notification list, and end the operation. the

After the topology change notification message is sent to the node routers in the topology change notification list, the node routers in the topology change notification list receive the topology change notification message and analyze it. According to the original protocol, the interior gateway protocol can only receive packets sent by directly connected neighbor routers. However, in the embodiment of the present invention, the interior gateway protocol can receive the topology change notification message sent by the non-directly connected remote node router. For security considerations, it is necessary to verify whether the IP address of the topology change notification message belongs to the interface IP address of the topology change initiation router. After the routers in the network pass the packet verification, they quickly synchronize the network database and perform routing calculations to achieve fast convergence. the

In the embodiment of the present invention, through unicast IP messages, that is, topology change notification messages, the topology change router sends the topology change notification messages of the entire network through the collected topology change notification list, so that the topology change information can be transmitted in a very short time. Intranet notification enables the network to quickly synchronize the network database, perform routing calculations, and improve network convergence speed. the

Embodiment 2 of the method for notifying network topology changes

The embodiment of the present invention provides another embodiment on the basis of the first embodiment of the present invention. FIG. 3 is a flowchart of the second embodiment of the method for notifying network topology changes of the present invention. As shown in FIG. 3 , it includes:

Step 21: Establish a fast advertising router virtual adjacency relationship. As shown in FIG. 3 , establishing the virtual adjacency relationship of the fast advertising router can be realized through a private protocol, an authentication request, or a network administrator's designation. The message that quickly advertises the router's virtual adjacency relationship is exchanged only once, and is used to establish an effective advertisement list to ensure network security. the

Step 22: Collect the node router information that needs to be notified in the network, and generate a list of topology change notifications;

Step 23: Obtain the link state message containing the network topology change information;

Step 24: Encapsulate the topology change notification message according to the obtained link state message containing the network topology change information;

Step 25: Send the encapsulated topology change notification message to the node routers in the topology change notification list, and end the operation. the

As shown in Figure 1, the topology change advertisement message of router 2 can only contain the message destined for router 1, and there are other node routers in the network in the advertisement list of router 1, then the topology change advertisement message of router 2 Only send to router 1, and router 1 re-encapsulates the message and sends it to other node routers in its own list. Through such grouping, it is possible to avoid the notification in Embodiment 1 of the present invention due to too many topological nodes in the network. The list is too large, which affects the sending efficiency. the

Embodiment 1 of a device for notifying network topology changes

Fig. 4 is a schematic structural diagram of Embodiment 1 of a notification device for network topology changes in the present invention. As shown in Fig. 4, the embodiment of the present invention includes:

The processing module 111 is used to collect node router information that needs to be notified in the network, and generate a topology change notification list;

Obtaining module 112, for obtaining the link state message that contains network topology change information;

The encapsulation module 113 is used for encapsulating the topology change notification message according to the obtained link state message containing the network topology change information;

The sending module 114 is configured to send the encapsulated topology change notification message to the node routers in the topology change notification list. the

Embodiment 2 of the notification device for network topology changes

FIG. 5 is a schematic structural diagram of Embodiment 1 of the device for notifying network topology changes of the present invention. As shown in FIG. It is used to establish the fast advertisement router virtual adjacency relationship. the

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that: it still Modifications or equivalent replacements can be made to the technical solutions of the present invention, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present invention. the

Claims (7)

1. A notification method for network topology changes, comprising: When the network topology changes, the node router information that needs to be notified in the network is collected, and a topology change notification list is generated, and the notification list is an Internet protocol address list of the node router on the shortest path first tree of the topology change initiation router; Obtain link state packets containing network topology change information; encapsulating a topology change notification message according to the acquired link state message containing network topology change information; sending the encapsulated topology change notification message to node routers in the topology change notification list; Before the collection of node router information that needs to be advertised in the network, it also includes establishing a fast-advertising router virtual adjacency relationship. 2. The notification method of network topology changes according to claim 1, characterized in that: said establishment of router virtual adjacency is implemented through private protocol, authentication request or network administrator designation. 3. the notification method of network topology change according to claim 1, is characterized in that: The topology change notification message carries the link state message containing the network topology change information, and the link state message containing the network topology change information is an open shortest path first link state broadcast or intermediate system to intermediate system link status message. 4. the notification method of network topology change according to claim 1, is characterized in that: encapsulating the topology change notification message according to the obtained link state message is specifically: encapsulating the topology change notification message into an Internet Protocol report The text; the source IP address of the topology change notification message is the IP address of the topology change initiation router interface; the destination IP address is the IP address of each node router interface in the topology change notification list. 5. The notification method of network topology change according to claim 4, characterized in that: the encapsulated topology change notification message is directly sent to each node router in the topology change notification list in a unicast manner. 6. The notification method of network topology changes according to claim 5, characterized in that: after sending the topology change notification message to the node routers in the topology change notification list, it also includes: after receiving the notification message Finally, it is verified whether the source IP address of the topology change notification message belongs to the interface IP address of the topology change initiating router. 7. A notification device for network topology changes, comprising: The processing module is used to collect node router information that needs to be notified in the network, and generate a topology change notification list, and the notification list is a list of Internet Protocol addresses of node routers on the shortest path first tree of the topology change initiation router; An acquisition module, configured to acquire a link state message containing network topology change information; An encapsulation module, configured to encapsulate a topology change notification message according to the acquired link state message containing network topology change information; A sending module, configured to send the encapsulated topology change notification message to node routers in the topology change notification list; The router virtual adjacency establishing module is used for establishing the fast advertisement router virtual adjacency.

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