[c-nsp] Question for LACP/LAG gurus

[Nick Ryce]

Im in the same situation as below, trying to get a LACP working between Extreme and an ASR 9k.  Does anyone have a workaround for this rather than resetting the system id of the Extreme kit?



Nick





> From: Dmitry Kiselev <dmitry at dmitry.net<https://puck.nether.net/mailman/listinfo/cisco-nsp>>

> To: cisco-nsp at puck.nether.net<https://puck.nether.net/mailman/listinfo/cisco-nsp>

> Date: Tue, 12 Apr 2011 14:49:24 +0300

> Subject: [c-nsp] Question for LACP/LAG gurus

> Hello!

>

> While building several new LAGs on IOS XR I found strange behaviour of

> Cisco IOSes for "system priority" LACP parameter. Most of classic IOSes

> allow to set value from 0 to 65535, but IOS XR does not:

>

> 12.2(55)SE2 Switch(config)#lacp system-priority ?

>  <0-65535>  Priority value

>

> 12.2(54)SG Switch(config)#lacp system-priority ?

>  <0-65535>  Priority value

>

> 12.2(33)SRE Router(config)#lacp system-priority ?

>  <0-65535>  Priority value

>

> IOS XE 12.2(33)XNF2 Router(config)#lacp system-priority ?

>  <0-65535>  Priority value

>

> IOS XR 4.0.1 Router(config)#lacp system priority ?

>  <1-65535>  Priority for this system. Lower value is higher priority.

>

> Moreover, IOS XR does not form the LAG if received partner system priority

> is zero.

> In this case each bundle port shows the error message "Partner System

> ID/Key

> do not match that of the Selected links" and remain "configured" state.

>

> It would remain a theoretical nuance, but Extreme Networks switches

> advertise

> priority=0 by default on all LAGs cousing some troubles in setup.

> Interesting

> fact thats in the same time zero is invalid value in Extreme switch

> configuration  :) :)

>

> Extreme# configure sharing 7 lacp system-priority ?

>  <system_priority>  System Priority (1..65535)

>

> I take a short look inside IEEE 802.1AX-2008 standart and IEEE 802.3-2005

> clause 43

> and does not see any special case for priority=0.  Does anybody in the list

> familar

> enough with LACP to explain me why Cisco IOS XR does not like zero here?

>

> Thanks

>

> --

> Dmitry Kiselev


Nick Ryce
Senior Network Engineer
Pulsant Limited
T: 0845 119 9900
DDI: +44 131 5144049
W: www.pulsant.co.uk<https://nbg01-exch-01.lumison.net/owa/redir.aspx?C=3d7cd71066064370b0210c73169f0074&URL=http%3a%2f%2fwww.pulsant.co.uk>


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