[c-nsp] Adding a second switch for redundancy

[Eric Kagan]

I am trying to lab the following - Several routers plugged in to two
seperate switches for redundancy.  Catalyst 3524XL/3550.  7200/7500 routers
- 


Design A (works fine - diagram below)

5 routers plugged in to a 3550 (configured as Layer 2 ports).  We are
running EIGRP on the routers.



Design B (EIGRP Errors - diagram below)

We added 2nd FE cards to the routers
We plugged them in to the new switch
We assigned a new / separate subnet for the interfaces. 

When we bring them up, we get EIGRP flaps. (log clip below)
Are there EIGRP settings that need to be changed for having 2 FE's from the
same routers in different switches ?  Do the switches need to be trunked ? 

Thanks
Eric



Design A: (working - single switch, multiple routers)


-----------------
|  Cat 3550-A   |
-----------------
  |   |   |   | ----- 1.1.1.0 /24 (EIGRP)
  R   R   R   R


Design B: (problem)


-----------------
|  Cat 3550-A   |
-----------------
  |   |   |   | ----- 1.1.1.0 /24 (EIGRP)
  R   R   R   R
  |   |   |   | ----- 2.1.1.0 /24 (EIGRP)
-----------------
|  Cat 3550-B   |
-----------------

When I bring up the ports I get EIGRP errors:



22:41:59 edt: %LINK-3-UPDOWN: Interface FastEthernet6/0, changed state to up
22:42:00 edt: %TDP-5-INFO: FastEthernet6/0: LDP started
22:42:00 edt: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEtherne
6/0, changed state to up
22:42:17 edt: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 65555: Neighbor
1.1.1.12(FastEthernet0/0) is down: Peer goodbye received
22:42:19 edt: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 65555: Neighbor
1.1.1.12(FastEthernet0/0) is up: new adjacency
22:42:29 edt: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 65555: Neighbor
2.1.1.11(FastEthernet6/0) is up: new adjacency
22:42:29 edt: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 65555: Neighbor
2.1.1.12(FastEthernet6/0) is up: new adjacency
22:43:39 edt: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 65555: Neighbor
1.1.1.12(FastEthernet0/0) is down: retry limit exceeded
22:43:39 edt: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 65555: Neighbor
1.1.1.12(FastEthernet0/0) is up: new adjacency
22:44:33 edt: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 65555: Neighbor
1.1.1.11(FastEthernet0/0) is down: Peer goodbye received
22:44:33 edt: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 65555: Neighbor
1.1.1.11(FastEthernet0/0) is up: new adjacency
22:44:34 edt: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 65555: Neighbor
1.1.1.5(FastEthernet0/0) is down: retry limit exceeded
22:44:34 edt: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 65555: Neighbor
1.1.1.4(FastEthernet0/0) is down: retry limit exceeded
22:44:34 edt: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 65555: Neighbor
1.1.1.5(FastEthernet0/0) is up: new adjacency
22:44:34 edt: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 65555: Neighbor
1.1.1.2(FastEthernet0/0) is down: retry limit exceeded
22:44:38 edt: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 65555: Neighbor
1.1.1.4(FastEthernet0/0) is up: new adjacency
22:44:39 edt: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 65555: Neighbor
1.1.1.2(FastEthernet0/0) is up: new adjacency
22:44:59 edt: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 65555: Neighbor
1.1.1.12(FastEthernet0/0) is down: Peer goodbye received
22:44:59 edt: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 65555: Neighbor
1.1.1.12(FastEthernet0/0) is up: new adjacency
22:45:53 edt: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 65555: Neighbor
1.1.1.11(FastEthernet0/0) is down: retry limit exceeded
22:45:53 edt: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 65555: Neighbor
1.1.1.11(FastEthernet0/0) is up: new adjacency
22:45:53 edt: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 65555: Neighbor
1.1.1.5(FastEthernet0/0) is down: retry limit exceeded
22:45:54 edt: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 65555: Neighbor
1.1.1.5(FastEthernet0/0) is up: new adjacency
22:45:57 edt: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 65555: Neighbor
1.1.1.4(FastEthernet0/0) is down: retry limit exceeded
22:45:58 edt: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 65555: Neighbor
1.1.1.4(FastEthernet0/0) is up: new adjacency
22:45:58 edt: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 65555: Neighbor
1.1.1.2(FastEthernet0/0) is down: retry limit exceeded
22:45:58 edt: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 65555: Neighbor
1.1.1.2(FastEthernet0/0) is up: new adjacency
22:46:19 edt: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 65555: Neighbor
1.1.1.12(FastEthernet0/0) is down: retry limit exceeded
22:46:24 edt: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 65555: Neighbor
1.1.1.12(FastEthernet0/0) is up: new adjacency
22:47:02 edt: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 65555: Neighbor
2.1.1.12(FastEthernet6/0) is down: holding time expired
22:47:12 edt: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 65555: Neighbor
2.1.1.11(FastEthernet6/0) is down: interface down
22:47:13 edt: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 65555: Neighbor
1.1.1.11(FastEthernet0/0) is down: retry limit exceeded
22:47:13 edt: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 65555: Neighbor
1.1.1.11(FastEthernet0/0) is up: new adjacency
22:47:14 edt: %LINK-5-CHANGED: Interface FastEthernet6/0, changed state to
administratively down
22:47:15 edt: %LINEPROTO-5-UPDOWN: Line protocol on Interface
FastEthernet6/0, changed state to down