Redistribution Notes – Tagging

• Tagging provides a way to mark common or similar routes to manipulate later.
• In redistribution scenarios with mutual redistribution on two different routers, any routes that gets redistributed from one route process to another are tagged.
  • When the other router sees those tags on the route, that route to keep from adding non-optimal routes to its routing table.
• Tags can also be used to do other manipulation such as setting higher metrics or changing ADs.

OSPF

R102#show run ... router ospf 1 log-adjacency-changes redistribute connected subnets route-map SETTAG network 192.0.2.0 0.0.0.255 area 0 ! route-map SETTAG permit 100 set tag 55555 ... R101#sh ip route 10.0.0.2 Routing entry for 10.0.0.0/24 Known via "ospf 1", distance 110, metric 20 Tag <strong>55555</strong>, type extern 2, forward metric 10 Last update from 192.0.2.102 on Ethernet0/0, 00:00:13 ago Routing Descriptor Blocks: * 192.0.2.102, from 192.0.2.102, 00:00:13 ago, via Ethernet0/0 Route metric is 20, traffic share count is 1 Route tag <strong>55555</strong>

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R102#show run ... router ospf 1 log-adjacency-changes redistribute connected subnets route-map SETTAG network 192.0.2.0 0.0.0.255 area 0 ! route-map SETTAG permit 100 set tag 55555 ...   R101#sh ip route 10.0.0.2 Routing entry for 10.0.0.0/24 Known via "ospf 1", distance 110, metric 20 Tag <strong>55555</strong>, type extern 2, forward metric 10 Last update from 192.0.2.102 on Ethernet0/0, 00:00:13 ago Routing Descriptor Blocks: * 192.0.2.102, from 192.0.2.102, 00:00:13 ago, via Ethernet0/0 Route metric is 20, traffic share count is 1 Route tag <strong>55555</strong>

EIGRP

R102#sh run ... router eigrp 1 network 192.0.2.0 redistribute connected route-map SETTAG no auto-summary ! route-map SETTAG permit 100 set tag 55555 ... R101#sh ip route 10.0.0.2 Routing entry for 10.0.0.0/24 Known via "eigrp 1", distance 170, metric 409600 Tag <strong>55555</strong>, type external Redistributing via eigrp 1 Last update from 192.0.2.102 on Ethernet0/0, 00:00:14 ago Routing Descriptor Blocks: * 192.0.2.102, from 192.0.2.102, 00:00:14 ago, via Ethernet0/0 Route metric is 409600, traffic share count is 1 Total delay is 6000 microseconds, minimum bandwidth is 10000 Kbit Reliability 255/255, minimum MTU 1500 bytes Loading 1/255, Hops 1 Route tag <strong>55555</strong>

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R102#sh run ... router eigrp 1 network 192.0.2.0 redistribute connected route-map SETTAG no auto-summary ! route-map SETTAG permit 100 set tag 55555 ...   R101#sh ip route 10.0.0.2 Routing entry for 10.0.0.0/24   Known via "eigrp 1", distance 170, metric 409600   Tag <strong>55555</strong>, type external   Redistributing via eigrp 1   Last update from 192.0.2.102 on Ethernet0/0, 00:00:14 ago   Routing Descriptor Blocks:   * 192.0.2.102, from 192.0.2.102, 00:00:14 ago, via Ethernet0/0       Route metric is 409600, traffic share count is 1       Total delay is 6000 microseconds, minimum bandwidth is 10000 Kbit       Reliability 255/255, minimum MTU 1500 bytes       Loading 1/255, Hops 1       Route tag <strong>55555</strong>

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Corrections are encouraged.

Aaron Conaway

I shake my head around sometimes and see what falls out. That's what lands on these pages.

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