Hi Guys,
i need some clarification on redistribution techniques. I was working on
Volume 1 Lab 15 and have two questions. The first is the method of route
filtering. I attended the online vLecture that Marko did on redistribution
and he used route-maps to prevent routing loops in the following manner.
Assume we have OSPF, EIGRP, RIP, and BGP in our network (only a single
Area/AS for each)
route-map ospf-to-eigrp deny 10
match tag 90
route-map ospf-to-eigrp permit 20
match tag 120
route-map ospf-to-eigrp permit 30
match tag 200
route-map ospf-to-eigrp permit 40
set tag 110
However in lab 15 the route-maps were written like this. Doesn't this
defeat the purpose of doing mutual redistribution? If one of the routing
domains goes way we will no longer have full reachability.
Example if we had EIGRP-------OSPF--------RIP EIGRP routes would not
make it to RIP.
route-map ospf-to-eigrp deny 10
match tag 90 120 200
route-map ospf-to-eigrp permit 40
set tag 110
Second Question is that in the DSG it was mentioned that BGP does not
support tags inbound OR outbound. I did know that when redistributing into
BGP you cant use the set tag but i was not aware that you can't look at the
tag attribute when redistributing from BGP to another protocol.
If do a show ip route for a BGP route it does show the tag for the
originating AS. So i would assume that if the question states don't
redistribute routes originating ins AS 64514 to RIP i could use the tag to
filter it. Can someone explain the caveats of the tag in BGP?
Routing entry for 102.12.0.0/22
Known via "bgp 64512", distance 200, metric 0
Tag 64514, type internal
Last update from 150.100.100.6 3d00h ago
Routing Descriptor Blocks:
* 150.100.100.6, from 150.100.100.6, 3d00h ago
Route metric is 0, traffic share count is 1
AS Hops 2
Route tag 64514
*> 102.12.0.0/22 150.100.100.6 0 100 0 (64514) 19999
3561 ?
Thanks in advance everyone
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