assume you have f.e. OSPF to EIGRP and vice versa on two routers for redundancy. To avoid routing loops you want to avoid redistributing back into OSPF, what originally came from OSPF ... and the other way round. One option is to LIST all networks with a prefix-list. This might not be feasible in a very dynamic environment or where many routes are to be handled.
So one can set a tag during OSPF to EIGRP redistribution and filter all routes with that tag when redistributing from EIGRP to OSPF.
This way you get a flexible configuration independant on the number of routes or networks in use.
The main idea is: a tag is nothing else as a specific "marking" to identify special routes. You could also say a tag is like an attribute, lets say "blue". Maybe the task is not to announce all "blue" routes to a certain location. The meaning of a tag is defined through the route-map and conditions therein to set the tag.
So in the redistribution case, a tag can mean "everything inserted into OSPF from EIGRP on a specific router doing redistribution".
In another router you could say: "If routes in EIGRP came from OSPF I do not want to reinject those routes back into OSPF". The question remains: How can a router know which networks where redistributed somewhere else in the network? Answer: The router should look for the specific tag which has this special meaning in your environment.
One router is setting the tags based on criteria, which you can define through a route-map. Another router will search for the tag and perform some actions based on another route-map.
We are pleased to announce availability of Beta software for 16.6.3.
16.6.3 will be the second rebuild on the 16.6 release train targeted
towards Catalyst 9500/9400/9300/3850/3650 switching platforms. We are
looking for early feedback from customers befor...
Introduction Featured Speakers Luis Espejel is the Telecommunications
Manager of IENova, an Oil & Gas company. Currently he works with Cisco
IOS® and Cisco IOS XE platforms, and NX to some extent. He has also
worked as a Senior Engineer with the Routing P...
In this session you can learn more about Layer 3 multicast and the best
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provides an overview of basic multicast, the best security practices for
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