For some reason when I lose layer 3 connectivity between two managed Ethernet sites EIGRP does not bounce.Is this because the physical interface does not bounce?
Correct. Eigrp neighbor connectivity has a short-cut when L2 connectivity goes down, otherwise it will use the eigrp neighbor hold-down timer. You can decrease that timer: interface fa0/0 ip hello-interval eigrp p x ip hold-time eigrp p y where p is your eigrp as-number, and x is how often you want the hello (in seconds) and y is the max hold-down timer. Generally y is = x * 3 http://www.cisco.com/en/US/docs/ios/12_2/iproute/command/reference/1rfeigrp.... ---- Matthew Huff | One Manhattanville Rd OTA Management LLC | Purchase, NY 10577 www.ox.com | Phone: 914-460-4039 aim: matthewbhuff | Fax: 914-460-4139 -----Original Message----- From: Philip Lavine [mailto:source_route@yahoo.com] Sent: Tuesday, September 23, 2008 11:43 AM To: nanog Subject: eigrp and managed ethernet For some reason when I lose layer 3 connectivity between two managed Ethernet sites EIGRP does not bounce.Is this because the physical interface does not bounce?
Yeah. If the link-layer failure is hidden from your routing protocol, then the routing protocol has to rely on its timer setting. When your EIGRP's hold-time expires, peering would bounce. Luan -----Original Message----- From: Philip Lavine [mailto:source_route@yahoo.com] Sent: Tuesday, September 23, 2008 11:43 AM To: nanog Subject: eigrp and managed Ethernet For some reason when I lose layer 3 connectivity between two managed Ethernet sites EIGRP does not bounce.Is this because the physical interface does not bounce?
On Tuesday 23 September 2008 11:43:06 Philip Lavine wrote:
For some reason when I lose layer 3 connectivity between two managed Ethernet sites EIGRP does not bounce.Is this because the physical interface does not bounce?
Because EIGRP hellos are sent via IP multicast, layer 3 connectivity is required to establish and maintain adjacencies. However, layer 3 failures aren't detected for, at most, 15 seconds by default on an Ethernet link. Stephen Kratzer Network Engineer CTI Networks, Inc.
participants (4)
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Luan Nguyen
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Matthew Huff
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Philip Lavine
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Stephen Kratzer