[j-nsp] ex-series: etherchannel bpdu loop ?

[Christopher E. Brown]

Check your cisco side configs, that config looks like a cisco 
"unconditional channel", not a lacp channel.

channel-group 1 mode on == HARD ETHER CHANNEL
channel-group 1 mode active == Active LACP or PAGP (depends on platform)


Some will need

channel-protocol lacp
channel-group 1 mode active

others default to lacp




Keegan.Holley at sungard.com wrote:
> I'm not terribly well versed in ex configuration, ( I think we're still 
> evaluating them) but it looks like you are trying to negotiate on the ex 
> end and then have it set on the cisco side so there may be a point in time 
> when the links aren't aggergated on the juniper side where traffic is 
> looped.
> 
> 
> 
> 
> 
> From:
> Alexandre Snarskii <snar at snar.spb.ru>
> To:
> Juniper-NSP Mailing list <juniper-nsp at puck.nether.net>
> Date:
> 03/18/2009 01:43 PM
> Subject:
> [j-nsp] ex-series: etherchannel bpdu loop ?
> Sent by:
> juniper-nsp-bounces at puck.nether.net
> 
> 
> 
> 
> Hi!
> 
> After power failure on one of our pop's we faced strange problem: 
> etherchannel between juniper ex-4200 and cisco 2960g started to 
> flap. By logs I saw that Cisco determined 'etherchannel 
> misconfiguration' condition, shuts down both ports of channel,
> then, after errdisable timeout, tried to set them up, but then 
> again detects etherchannel misconfiguration and so on and on... 
> 
> By Cisco documentation, etherchannel misconfiguration means 
> that BPDU's sent on one ports of etherchannel returned back 
> via another port. And forwarding of those BPDU from one
> LAG member interface to another (rstp is disabled on juniper)
> smells like an error in JunOS... 
> 
> Workaround: delete interfaces from LAG on Juniper, commit,
> add interfaces to LAG, commit. 
> 
> PS: Configuration is pretty straightforward on both sides: 
> 
> Juniper: 
> 
> snar at SW006-201> show configuration interfaces ae0 
> aggregated-ether-options {
>     minimum-links 1;
>     link-speed 1g;
> }
> unit 0 {
>     family ethernet-switching {
>         port-mode trunk;
>         vlan {
>             members all;
>         }
>     }
> }
> snar at SW006-201> show configuration interfaces ge-0/0/15 
> ether-options {
>     speed {
>         1g;
>     }
>     802.3ad ae0;
> }
> snar at SW006-201> show configuration protocols 
> [....]
> stp {
>     disable;
> }
> rstp {
>     disable;
> }
> mstp {
>     disable;
> }
> 
> 
> Cisco: 
> 
> Cisco#show runn int po1
> interface Port-channel1
>  switchport mode trunk
>  mvr type source
> Cisco#show runn int gi 0/23
> interface GigabitEthernet0/23
>  switchport mode trunk
>  load-interval 30
>  channel-group 1 mode on
> 
> 
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> 
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