12-15-2016 08:23 AM - edited 03-08-2019 08:35 AM
Hi there,
Thanks for reading.
I'm finding a physical inf in UP/DOWN (Suspended) state. Investigation shows a problem with our initial configuration and a clear fix: set 1/0/6 mode:trunk.
interface GigabitEthernet1/0/5
description swuk602-po2
switchport mode trunk
channel-group 2 mode active
!
interface GigabitEthernet1/0/6
description swuk602-po2
channel-group 2 mode active
My question is: what happens to the port channel when I fix the 1/0/6 mode? Right now, the other inf is carrying the Po which shows up/up (connected). Will I bounce the Po if I change properties of 1/0/6? Is it a single ping lost or down for 15-20 seconds or so?
Thanks!
Bob
Solved! Go to Solution.
12-15-2016 08:41 AM
Bob,
In my opinion...
You are basically adding a channel into the port-channel.
There should be no adverse affect on existing traffic.
The switch will build up it data table for load sharing across the port-channel
and packet will be sent on the interface selcting from the channelling HASH mechanism.
It is more likely you would drop a ping or 2 when an interface is lost and an existing
IP or MAC stream has to re-route.
May be this link will help:-
http://www.cisco.com/c/en/us/support/docs/lan-switching/etherchannel/12023-4.html
Regards
Alex
12-15-2016 08:41 AM
Bob,
In my opinion...
You are basically adding a channel into the port-channel.
There should be no adverse affect on existing traffic.
The switch will build up it data table for load sharing across the port-channel
and packet will be sent on the interface selcting from the channelling HASH mechanism.
It is more likely you would drop a ping or 2 when an interface is lost and an existing
IP or MAC stream has to re-route.
May be this link will help:-
http://www.cisco.com/c/en/us/support/docs/lan-switching/etherchannel/12023-4.html
Regards
Alex
12-15-2016 01:27 PM
Hi guys,
Thanks for replying!
I sourced a couple of 3750s after PacketTracer failed to accurately represent the layout (the phy inf stayed up/up after moving from trunk to access).
I found I was able to move a member of the port channel in and out of the group (trunk->access->trunk) without the port channel inf resetting. Consistent with gpauwen's findings, the physical interface took about 15-20 seconds to negotiate and change to up/up but the Port Channel logged no losses.
Thanks again!
12-15-2016 09:28 AM
Hello,
I labbed this in GNS, and both removing and adding a port to the channel led to a 30 second timeout on the connection between end hosts on either side of the channel. This is (I think) due to STP coonvergence.
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