[c-nsp] Gracefully remove a port from Etherchannel

Ed Butler ed.butler at rapidswitch.com
Thu Jun 8 16:38:09 EDT 2006


Interesting, our configuration doesn't seem to have a default port:
#show etherchannel 2 summary
[snip]
Number of channel-groups in use: 2
Number of aggregators:           2

Group  Port-channel  Protocol    Ports
------+-------------+-----------+---------------------------------------
--------
2      Po2(SU)         LACP      Gi1/0/25(P) Gi2/0/20(P) 


Regards,

Ed Butler
RapidSwitch Ltd
DDI: 020 7106 0731

RapidSwitch Ltd, 5th Floor, Sovereign House, 227 Marsh Wall, London, E14
9SD

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-----Original Message-----
From: Roldan, Brad [mailto:broldan at Covad.COM] 
Sent: 08 June 2006 18:57
To: Ed Butler; cisco-nsp at puck.nether.net
Subject: RE: [c-nsp] Gracefully remove a port from Etherchannel


If I recall correctly, Cisco will designate a specific link in the
etherchannel bundle for multicast traffic. If you kill the "default"
port, you'll likely see some OSPF resets. Maybe someone else on the list
has better information.

Cisco2950#sh  etherchannel 1 summary
Flags:  D - down        P - in port-channel
        I - stand-alone s - suspended
        R - Layer3      S - Layer2
        u - unsuitable for bundling
        U - port-channel in use
        d - default port
	^^^^^^^^^^^^^^^^^^^
Group Port-channel  Ports
-----+------------+-----------------------------------------------------
------
1     Po1(SU)     Fa0/21(Pd) Fa0/22(P)  Fa0/23(s)  Fa0/24(P)
			^^^^^^^^^^
Cisco2950#

Regards,

Brad
--
Covad Communications
2510 Zanker Road
San Jose, CA 95131 
+1-408-434-2048
broldan at covad.com 


-----Original Message-----
From: cisco-nsp-bounces at puck.nether.net
[mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Ed Butler
Sent: Thursday, June 08, 2006 1:32 AM
To: cisco-nsp at puck.nether.net
Subject: [c-nsp] Gracefully remove a port from Etherchannel


Yesterday we unplugged a port from etherchannel, and were not expecting
this to affect traffic flow. However, the logs on the Cisco 3750 show
the OSPF adjacency went down and immediately came back up.

20w1d: %LINEPROTO-5-UPDOWN: Line protocol on Interface
GigabitEthernet1/0/24, changed state to down
20w1d: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/24, changed state to
down
20w1d: %OSPF-5-ADJCHG: Process 1, Nbr x.y.x.y on Vlan164 from FULL to
DOWN, Neighbor Down: Dead timer expired 
20w1d: %OSPF-5-ADJCHG: Process 1, Nbr x.y.x.y on Vlan164 from LOADING to
FULL, Loading Done

1) Is this supposed to happen?
2) Is there a way of gracefully removing a port from an etherchannel (eg
shutdown) to ensure problems don't get caused?
3) If the answers to the above are "Yes" and "No" respectively, should
etherchannel be used to give some redundancy?

Thanks,

Regards,

Ed Butler
RapidSwitch Ltd
DDI: 020 7106 0731

RapidSwitch Ltd, 5th Floor, Sovereign House, 227 Marsh Wall, London, E14
9SD

This email message is intended only for the addressee(s) and contains
information that may be confidential and/or copyright.  If you are not
the intended recipient please notify the sender by reply email and
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prohibited. No representation is made that this email or any attachments
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