We have two buildings, connected via 2 x 100Mb laser links. The switches on both ends are not Cisco, but are configured to be in a 'channel'. The lasers on both sides go into copper/fiber convertors, and then into the switches. The obvious problem here is that the switches will not notice when anything else other than the convertor fails (like laser, fiber etc). They will still have connectivity to the convertors, and thus happily pass traffic to the dead laser, which effectively brings both links down.
If I were to replace the switches with Cisco boxes, configure keepalives on all for ports, and form a channel, will a failure to receive keepalives not result in a port connected to a 'dead laser' shutting down (and thus resolving the problem)?
Jacques, this is an interesting scenario. I can't say definitively, but it appears that your idea may work.
The default for switch keepalives is 10sec and bundling the ports together in a FEC would bring some resiliency b/c an EtherChannel actually tracks which physical ports are active in order to avoid spanning tree loops (the Port Channel is treated as one large logical pipe for STP purposes).
I think it sounds like a good idea. Check out this page for more info on EtherChannel:
I think I must test this with some 2950s we have. They will not carry the load under normal conditions, but before I put in a order for bigger boxes, I must be sure it will work (My idea of having 2 lasers for redundancy went a bit wrong!).
This is actually a pretty cool feature, i didn't even know it existed until I was looking for a solution to advertise a subnet (prefix in BGP talk), only if a certain condition existed. This is exactly what conditional advertisements does
j ai une question j ai achete un routeur cisco 887VA-k9 , je le configuré avec la configuration ci- dessous
si je le lier avec mon pc portable sur l un de ses ports directement ça marche toute est bien ( la connexion internet + m...
Attached policy provides CLI access to the Cisco 4G router over text messaging. Two files are in the attached .tar file:
2. PDF with instructions on how to load and use the .tcl file.