tailieunhanh - The Complete IS-IS Routing Protocol- P35

The Complete IS-IS Routing Protocol- P35: IS-IS has always been my favourite Interior Gateway Protocol. Its elegant simplicity, its well-structured data formats, its flexibility and easy extensibility are all appealing – IS-IS epitomizes link-state routing. Whether for this reason or others, IS-IS is the IGP of choice in some of the world’s largest networks. | 340 12. IP Reachability Information Figure . Admin tags are a convenient way of implementing an AS-wide policy for leaking 32s IOS command output London show isis database level-1 verbose IS-IS Level-1 LSP LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT P OL OxOOOOOOIO 0x574C 819 0 0 0 Area Address NLPID 0xCC Hostname London IP Address Metric 0 IP 32 Route Admin Tag 200 Domain-wide Prefix Distribution 341 Metric 10 IP 24 Metric 10 IS-Extended The second IOS policy now needs to match against all previously tagged prefixes. See the example below which uses a route-map for achieving that purpose. IOS configuration To match against the previously tagged prefixes you need to unconfigure the redistribute isis ip level-2 into level-1 distribute-list 166 command and use the redistribute isis ip level-2 into level-1 route-map command instead. This commands points to a route-map which has far more fine-grained control than an access list would offer. London show running-config router isis redistribute isis ip level-2 into level-1 route-map leak-tagged-L2-to-L1 passive-interface Loopback0 net metric-style wide route-map leak-tagged-L2-to-L1 permit 10 match tag 200 . The route-map leak-tagged-L2-to-L1 is fairly simple. It permits all prefixes which carry the tag 200 and report it back to the IS-IS redistribution process for inclusion in the Level-1 database. You can verify the results of your policy by using the show isis database lsp-id verbose command. The verbose modifier also displays the Admin tags which the detail modifier does not. IOS command output London show isis database level-1 verbose IS-IS Level-1 LSP LSPID LSP Seq Num LSP Checksum 0x0000000D 0x8140 Area Address NLPID 0xCC Hostname London IP Address LSP Holdtime ATT P OL 797 0 0 0 342 12. IP Reachability Information Metric 0 .