[c-nsp] Etherchannel problem

[Joseph Mays]

> RtrA(216.24.2.201,205)----SwA====SwB----RtrB(216.24.2.202,206)

Got the vlan problem fixed. Now on to a related, but slightly different problem with the same set of ports.

I actually want the ethernet connections between SwA and SwB to be etherchannel port groups on vlan808. As I said, SwB is a 2924, and they don't support interface ranges. I put the ports on SwB in a port group, and SwA into an etherchannel group, and it seems to work, except pings from off the router on the RtrA lan receive duplicate packet responses. When I ping from the routers on either side they don't show duplicate packets, but then I've never seen a duplicate packet response on a cisco ping so I'm not sure how it gets represented.

Ping from RtrA to RtrB across the bundled ethernet ports between SwA and SwB

gw1.armplc#ping 216.24.2.201

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 216.24.2.201, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/4 ms

Ping from a FreeBSD machine on the lan behind RtrA. Note that this ping did not show duplicate packet responses until I had the ethernet ports bundled.

admin1# ping 216.24.2.202
PING 216.24.2.202 (216.24.2.202): 56 data bytes
64 bytes from 216.24.2.202: icmp_seq=0 ttl=254 time=1.755 ms
64 bytes from 216.24.2.202: icmp_seq=0 ttl=254 time=1.953 ms (DUP!)
64 bytes from 216.24.2.202: icmp_seq=1 ttl=254 time=4.208 ms
64 bytes from 216.24.2.202: icmp_seq=1 ttl=254 time=4.446 ms (DUP!)

Here are the etherchannel and port group configs on the routers

RtrA (2950)

interface Port-channel2
!
interface FastEthernet0/1
description Link via HN408U #1 to sw1.armplc FE0/10
switchport trunk allowed vlan 808
switchport mode trunk
speed 100
duplex full
channel-group 2 mode desirable
!
interface FastEthernet0/2
description Link via HN408U #2 to sw1.armplc FE0/17
switchport trunk allowed vlan 808
switchport mode trunk
speed 100
duplex full
channel-group 2 mode desirable

RtrB (2924XL)

interface FastEthernet0/10
description Link via HN408U #1 to sw1.armplc FE0/1
duplex full
speed 100
port group 2
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 1,808,1002-1005
switchport mode trunk
no cdp enable
!
interface FastEthernet0/17
description Link via HN408U #2 to sw1.armplc FE0/2
duplex full
speed 100
port group 2
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 1,808,1002-1005
switchport mode trunk
no cdp enable