Re: eigrp flap

It is not a technical requirement of EIGRP that the timers match on both
sides to form an adjacency, but not having them match CAN cause big issues
or be a part of those issues especially when you are having issues with
packet loss. Looking at your outputs, I would suspect you are having some
packet loss here. On router B you have a significantly high SRTT for an
ethernet environment and 189 suppressed ACKs. I would start with trying to
research those issues. Also, take a look at "show ip eigrp neighbor" and
post it if you like. You might check out your RTO, Q Cnt and SRTT
statistics there to do more digging.

HTH

On Tue, Apr 10, 2012 at 1:05 PM, chris <jpn.chris_at_gmail.com> wrote:

> Hello, expert. during the lab study, I met eigrp bouncing as shown
> below,.. after isolation, the problem was resolved with removing "ip
> hello-interval eigrp 100 10" on each site. feel weird since my
> understanding was the interval tuning does not bring impact the adjacency
> in the eigrp case... Could anyone kindly explain the mechanism and
> his(DUAL) logic?
>
>
> *Mar 1 00:20:49.039: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor
> 135.15.20.5 (Vlan30) is down: Peer
> *Mar 1 00:20:49.063: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor
> 135.15.20.4 (Vlan30) is down: Peer
> *Mar 1 00:20:50.859: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor
> 135.15.20.4 (Vlan30) is up: new adj
> *Mar 1 00:20:50.863: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor
> 135.15.20.5 (Vlan30) is up: new adj
> *Mar 1 00:20:57.995: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor
> 135.15.20.4 (Vlan30) is down: Peer
> *Mar 1 00:21:00.363: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor
> 135.15.20.4 (Vlan30) is up: new adj
> *Mar 1 00:21:07.491: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor
> 135.15.20.30 (Vlan30) is down: Peer
> *Mar 1 00:21:10.123: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor
> 135.15.20.30 (Vlan30) is up: new ad
> *Mar 1 00:21:16.623: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor
> 135.15.20.30 (Vlan30) is down: Peer
> *Mar 1 00:21:19.731: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor
> 135.15.20.30 (Vlan30) is up: new ad
> *Mar 1 00:21:26.515: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor
> 135.15.20.30 (Vlan30) is down: Peer
> *Mar 1 00:21:26.535: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor
> 135.15.20.4 (Vlan30) is down: Peer
> *Mar 1 00:21:28.971: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor
> 135.15.20.4 (Vlan30) is up: new adj
> *Mar 1 00:21:28.975: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor
> 135.15.20.30 (Vlan30) is up: new ad
> *Mar 1 00:21:34.079: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor
> 135.15.20.4 (Vlan30) is down: Peer
>
>
>
> RouterA(config-if)#do show ip eigrp int de
> IP-EIGRP interfaces for process 100
>
> Xmit Queue Mean Pacing Time Multicast
> Pending
> Interface Peers Un/Reliable SRTT Un/Reliable Flow Timer
> Routes
> Vl30 4 0/0 85 0/1 408
> 0
> Hello interval is 10 sec
> Next xmit serial <none>
> Un/reliable mcasts: 0/109 Un/reliable ucasts: 428/303
> Mcast exceptions: 50 CR packets: 44 ACKs suppressed: 58
> Retransmissions sent: 20 Out-of-sequence rcvd: 18
> Authentication mode is md5, key-chain is "KEY"
> Use multicast
>
> RouterB(config-if)#do show ip eigrp int de
> IP-EIGRP interfaces for process 100
>
> Xmit Queue Mean Pacing Time Multicast
> Pending
> Interface Peers Un/Reliable SRTT Un/Reliable Flow Timer
> Routes
> Fa0/0 4 0/0 327 0/10 1244
> 0
> Hello interval is 10 sec
> Next xmit serial <none>
> Un/reliable mcasts: 0/338 Un/reliable ucasts: 1235/736
> Mcast exceptions: 43 CR packets: 39 ACKs suppressed: 189
> Retransmissions sent: 134 Out-of-sequence rcvd: 122
> Authentication mode is md5, key-chain is "KEY"
>
> RouterA(config-router)#do show run | sec router eigrp
> router eigrp 100
> network 135.15.20.0 0.0.0.255
> auto-summary
>
> RouterB(config-router)#do show run | sec router eigrp
> router eigrp 100
> network 135.15.20.0 0.0.0.255
> auto-summary
>
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"He not busy being born is busy dying" - Dylan
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