Next hop determining method and device

Abstract

The embodiment of the invention provides a next hop determining method and device. The method is applied to a first ASBR in a first autonomous system. A first autonomous system and a second autonomous system carry out cross-domain networking in an Option B mode. The second autonomous system comprises at least two second ASBRs. The method comprises the steps of detecting whether a preselection next hop currently corresponding to a target address is reachable or not, wherein the target address is the address of a target CE in the second autonomous system, the preselection next hop is the second ASBR with target identification information in a target forwarding table, and the target forwarding table is the forwarding table which is stored by the first ASBR and corresponds to the target address; if the preselection next hop is unreachable, selecting the identification information with the highest priority except the target identification information from the target forwarding table, wherein corresponding relationships between the identification information and the priorities are stored in the target forwarding table; and updating the preselection next hop corresponding to the target address to be the second ASBR with the selected identification information. Visibly, according to the scheme, the condition that traffic is interrupted for a long time among the autonomous systems which carry out cross-domain networking in the Option B mode can be avoided well.

Description

technical field [0001] The present invention relates to the field of communication technologies, in particular to a method and device for determining a next hop. Background technique [0002] In the field of communication technology, in order to break through the limitation of a single service provider's management domain, the technology of cross-domain networking of different autonomous domains is more and more widely used. Specifically, Option B (single-hop MP-EBGP, that is, single-hop multi-protocol border gateway protocol) mode can be used for cross-domain networking between different autonomous systems. [0003] When Option B is used for cross-domain networking, there are often certain problems. The following examples illustrate. [0004] see figure 1 , which shows a schematic diagram of the system structure when two autonomous systems (namely AS1 and AS2) form a cross-domain network through Option B. Wherein, AS1 has an autonomous system boundary router (ASBR1), and...

AI Technical Summary

Problems solved by technology

When ASBR1 detects that its link to ASBR2 fails, or ASBR2 itself fails, ASBR1 will perform a series of complicated procedures to re-determine the new next hop corresponding to the destination address CE2. It takes a long time. During this process, ASBR1 cannot transmit the received data packets with the destination address of CE2 to CE2. At this time, the traffic between AS1 and AS2 will be interrupted for a long time.

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