[c-nsp] Cisco 3020 blade switches hung, HLFM errors, network meltdown?

[Fredrik Jacobsson]

In a stp troubleshooting paper on cco, I saw a recommendation to run
pagp (non-silent) due to it's ability to select/negiotiate which port
in the bundle to run stp on. Also to prevent that the configs differ
and shut down inconsistant ports.

(was a while and I dont have a photographic memory so please dont kill
me if I'm wrong)

Is that setup (desirable non-silent) still considered best practise?
(I've noticed that many use "on" nowadays, hence not using pagp/lacp)

Thanks
/Fredrik

2008/3/20, matthew zeier <mrz at velvet.org>:
>
> On Mar 19, 2008, at 5:18 PM, Lincoln Dale wrote:
>
> > Hi Matthew,
> >
> > not a specific diagnosis to your problem, but i think this is a bit
> > of a warning here:
> >
> > matthew zeier wrote:
> >> Felt like a broadcast storm or even a spanning-tree loop but I'd be
> >> surprised if it was the latter and the upstream switches, two
> >> 6500s, didn't know how to do deal with that (heck, they deal with
> >> HP 2510s that default to not running spanning-tree).
> >>
> > if you had switches in your network NOT running STP, you've got a
> > pretty good opportunitiy for "bad things<tm>" to happen.
> >
> > were those switches connected with >1 link?
>
> Yes and for all the Vlans I have, one uplink is blocked :
>
> Interface        Role Sts Cost      Prio.Nbr Type
> ---------------- ---- --- --------- --------
> --------------------------------
> Po1              Root FWD 3         128.72   P2p
> Po2              Altn BLK 3         128.80   P2p
>
> Native Vlan on 0/16 was changed which broke the bundle and everything
> else.  One upstream switch is the other 3020 in the same chassis - the
> other is a 6500 which is also running pvst.   I would have figured
> something would have noticed a look at shut something down (if it was
> a STP loop anyways).
>
> interface Port-channel1
>  description to_core2:po100
>  switchport trunk encapsulation dot1q
>  switchport trunk native vlan 2
>  switchport mode trunk
>
> interface Port-channel2
>  switchport trunk encapsulation dot1q
>  switchport trunk native vlan 2
>  switchport mode trunk
>
> interface GigabitEthernet0/17
>  description to_core2:7/32
>  switchport trunk encapsulation dot1q
>  switchport trunk native vlan 2
>  switchport mode trunk
>  logging event bundle-status
>  logging event spanning-tree
>  channel-group 1 mode on
> !
> interface GigabitEthernet0/18
>  description to_core2:7/33
>  switchport trunk encapsulation dot1q
>  switchport trunk native vlan 2
>  switchport mode trunk
>  logging event bundle-status
>  logging event spanning-tree
>  channel-group 1 mode on
>
> interface GigabitEthernet0/23
>  switchport trunk encapsulation dot1q
>  switchport trunk native vlan 2
>  switchport mode trunk
>  logging event bundle-status
>  logging event spanning-tree
>  media-type internal
>  channel-group 2 mode on
> !
> interface GigabitEthernet0/24
>  switchport trunk encapsulation dot1q
>  switchport trunk native vlan 2
>  switchport mode trunk
>  logging event bundle-status
>  logging event spanning-tree
>  media-type internal
>  channel-group 2 mode on
>
>
>
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