EtherChannel Issues

[intel865]

I have created an Etherchannel of 200 Mbps between a Cisco 3550 L3 Switch and a Nortel Baystack 425 L2 Switch. Last evening I observed that one of the Etherchannl Ports on the Nortel Switch has stopped functioning. The result was that there was looping in the network and the error message was Duplicate IP found on the network as a result of which the entire network went down. On detailed analysis it was observed that the Duplicate IP advertised was that of the Cisco 3550 Switch. My question is
1. Can one port failure of the Etherchannel bring down the entire network
2. Why was it advertising its own ip and mentioning it as duplicate IP

 

[marks66]

I always configure my port-channel and interface with the same trunk informarion. See Below

interface Port-channel1
description FRC-MSFC-129
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 22,197,700,800,900
switchport mode trunk
logging event bundle-status
!
interface GigabitEthernet1/0/49
description FRC-MSFC-129
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 22,197,700,800,900
switchport mode trunk
logging event trunk-status
channel-group 1 mode on
!
interface GigabitEthernet1/0/50
description FRC-MSFC-129
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 22,197,700,800,900
switchport mode trunk
logging event trunk-status
channel-group 1 mode on
end

I think if you only specify trunking on the channel, when it is no longer a channel, eg one of the links is down, you get errors.

 

[burtsbees]

Is there another node with that IP address? Also, a loop will bring down the entire network in a second, usually due to broadcast storms.

Burt