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New Member

Redistribution of OSPF Routes into EIGRP

When redistributing OSPF Routes into EIGRP, a route to "LAN A" learned from OSPF are marked "D EX ".

When the LAN A is down, how long does it take to the DUAL process to be aware that the LAN A is no more reachable, in order to search for a Feasible successor or a new successor ?

In other words, how long does the entry "D EX" related to LAN A is maintained in the EIGRP routing table once the LAN A is down ?

4 REPLIES
Bronze

Re: Redistribution of OSPF Routes into EIGRP

Interesting question... Hopefully someone has an exact answer. I'd assume that OSPF immediately tells EIGRP of the route change, but that's just a guess.

New Member

Re: Redistribution of OSPF Routes into EIGRP

Happens almost immediately. Just checked this e0/0 ---------------RT04-------------------RT07---------------RT05 OSPF | EIGRP As above, RT07 redistributes OSPF from RT04 to EIGRP neighbor RT05. Interface e0/0 has IP address 172.20.23.160/16. With NTP running between routers, this is what I see when shutdown is configured on RT04 e0/0, with debug ip routing turned on. I tried to automate this a little by pasting this into RT04's console sh clock conf t int e0/0 shut On RT04.... RT04#sh clock 14:31:18.852 GMT Fri Nov 15 2002 RT04#conf t Enter configuration commands, one per line. End with CNTL/Z. RT04(config)#int e0/0 RT04(config-if)#shut RT04(config-if)# Nov 15 14:31:19.048: RT: interface Ethernet0/0 removed from routing table Nov 15 14:31:19.048: RT: del 172.20.0.0 via 0.0.0.0, connected metric [0/0] Nov 15 14:31:19.048: RT: delete network route to 172.20.0.0 RT04(config-if)# Nov 15 14:31:20.948: %LINK-5-CHANGED: Interface Ethernet0/0, changed state to ad ministratively down Nov 15 14:31:21.949: %LINEPROTO-5-UPDOWN: Line protocol on Interface Ethernet0/0 , changed state to down On RT07.... Nov 15 14:31:24.488: RT: del 172.20.0.0 via 192.168.1.2, ospf metric [110/74] Nov 15 14:31:24.488: RT: delete network route to 172.20.0.0 On RT05.... Nov 15 14:31:24.530: RT: delete route to 172.20.0.0 via 192.168.2.1, eigrp metric [170/2195456] Nov 15 14:31:24.530: RT: no routes to 172.20.0.0 Nov 15 14:31:25.534: RT: garbage collecting entry for 172.20.0.0 According to my calcs, it takes approx 2.5 secs for OSPF to withdraw the route at RT07, but EIGRP is updated and the remote is removed on RT05 within 1 second. Hope this helps.

New Member

Re: Redistribution of OSPF Routes into EIGRP

Sorry for the lack of clarity - proportional fonts are useless for graphics. The router doing redistribution is, of course, RT07.

New Member

Re: Redistribution of OSPF Routes into EIGRP

Thank you very much for your quick replay. I really appriciate your example.

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