Device for searching route

Abstract

The device is in use for IPv6 network. The device includes addressable memory of content in three stages, first comparator between addressable memory of content in first stage and addressable memory of content in second stage, second comparator between addressable memory of content in second stage and addressable memory of content in third stage. Since prefixion storage in each area of storage in addressable memory of content in each stage is not needed to consider, the disclosed device can carry out updating list item quickly. Moreover, in procedure of updating list item, flow for searching route is only interrupted for once. Thus, the invention has high continuity for searching route.

Description

technical field [0001] The present invention relates to route search technology, more specifically, the present invention relates to a route search device applied in IPv6 network. Background technique [0002] Internet protocol routing and forwarding table line speed lookup technology is one of the key technologies of core backbone routers. Routing lookup refers to determining the output port number and next-hop address that should be forwarded for each arriving IP packet according to its destination IP address. In order to improve the utilization of IPv4 address space and slow down the growth rate of entries in the routing table, the Internet working group IETF proposed the Classless Inter-domain Routing-CIDR technology in 1993. The length of the address prefix can be no more than Arbitrary length for IPv4 address width. The use of variable-length address prefixes makes it possible to assign IP addresses hierarchically, but it is possible to find multiple matching routing...

AI Technical Summary

Problems solved by technology

Since routing table items need to be updated continuously in practical applications, table item updating will interrupt the table lookup process, and TCAM simply outputs the storage address of the matching table item with the lowest address as the result (index), so the longest prefix match must be guaranteed. The storage of entries must be arranged in descending order according to the length of the prefix relative to the storage address. Therefore, inserting an entry into TCAM sometimes requires dozens of dimension order operations, which interrupts the routing lookup process dozens of times. This not only affects the timely update of routing entries, but also makes the query Table continuous performance drops dramatically

[0006] In order to overcome the above disadvantages, the existing technology further improves the update speed of entries by reducing the number of entries required to insert entries in sequence. Although the average efficiency of routing updates has been improved, the preprocessing operation is complicated and the worst In case of expensive update

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