[c-nsp] The network went down

[Alexandra Alvarado]

Hello,

Well, I have enabled all backbone ports with trunk feature with "allow all
vlans", en effectively I have
been enabled "vlan dot1q tag native" in allmost all 50 switches, exists 4
switches that had disabled that feature (now is enabled).  But until now I'm
not using QinQ.  In spite of that I have working 9 redundant link without
problem.

Thanks

Alexandra Alvarado


----- Original Message ----- 
From: "Nicolaj Ottsen" <no at webpartner.dk>
To: "Alexandra Alvarado" <aaaa at telconet.net>; <cisco-nsp at puck.nether.net>
Sent: Friday, September 17, 2004 2:44 PM
Subject: RE: [c-nsp] The network went down


> Hi,
>
> If you use "vlan dot1q tag native", you can get this problem if you
> forget to enable it on one switch with redundant links. I guess any type
> of misconfiguration could cause this. L2, with this many switches, is a
> tricky thing because small problems does not excist only disasters. I
> would seriously consider using the L3 functions in the 3550. Use L3
> (OSPF) to create redundancy at the "core" and L2 for redundancy at
> department level ... If not L3 all the way.
>
> Also remember to secure your access ports to prevent disaster.
>
> Interface X x/x
>  spanning-tree bpdufilter enable
>  spanning-tree bpduguard enable
>  spanning-tree guard root
>
> To automaticly bring the network back up after a failure enable
> "errdisable recovery", below is a list of what the switch can react to.
>
> errdisable recovery interval 30
>
> errdisable recovery cause udld
> errdisable recovery cause bpduguard
> errdisable recovery cause security-violation
> errdisable recovery cause channel-misconfig
> errdisable recovery cause pagp-flap
> errdisable recovery cause dtp-flap
> errdisable recovery cause link-flap
> errdisable recovery cause l2ptguard
> errdisable recovery cause psecure-violation
> errdisable recovery cause gbic-invalid
> errdisable recovery cause dhcp-rate-limit
> errdisable recovery cause unicast-flood
> errdisable recovery cause vmps
> errdisable recovery cause loopback
>
> /Nicolaj
>
>
> -----Original Message-----
> From: Alexandra Alvarado [mailto:aaaa at telconet.net]
> Sent: 17. september 2004 21:01
> To: cisco-nsp at puck.nether.net; Alexandra Alvarado
> Subject: [c-nsp] The network went down
>
>
>   ----- Original Message -----
>   From: Alexandra Alvarado
>   To: cisco-nsp at puck.nether.net ; Alexandra Alvarado
>   Sent: Thursday, September 16, 2004 6:40 PM
>   Subject: The network went down!
>
>
>   Hello,
>
>   Since 2 weeks ago I configured MSTP in the network that I manage, all
> was success, when a link fails, the backup link is activated
>   automatically in 1 second.
>
>   I have 9 redundant links approximately, in around 50 cisco switches
> catalyst 3550, all of them are part of one region.
>
>   Today I try to activate a new redundant link and all the network went
> down, the 90% of the switches stayed out, and the switches
>   that I could reach had in the log message "crash memory"; I supose
> that was a loop, but I have reviewed too many times and
>   I can't find any bad configuration. I had to reload all switches to
> get connectivity again and shut down the link that caused the problem.
>
>   Can anybody help to me giving some tips about it.
>
>   Thanks
>
>   Alexandra Alvarado
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