Wireless link failover options

Nikumba

Nikumba

Nikumba

Soldato
Joined
4 Dec 2002
Posts
3,983
Location
Bourne, Lincs
Morning all,

After some ideas, suggestions with a problem we have here at work.

We currently have a long range point to point wireless link running at 1Gb with a backup of 100Mb, both these links plug into one of our Extreme switch stacks.

Switch > Fibre Converter > Fibre > Fibre Converter > Cat 5 > Antenna then reverse on the other site and that is the same for both links.

Now only one port should be active on the switch, however we believe both ports became active and caused a mini-broadcast storm creating large packet loss on our network. Shutting down one of the ports resolved the issue, on our network we use EAPS rather than spanning tree.

We are talking to the people who supplied our wireless link about options, but wondering what the OCUK guys can think of.

Ideally want to have one connection from the switch to a box where both wireless links are plugged in and that handles the failover from the 1Gb link to the 100Mb link, but not sure what kind of box is best for this.

So over to you lot, for suggestions, ideas, questions etc

Cheers

Kimbie
 
Do devices on either side of the link need to be L2 adjacent? If you made the two links L3 and used OSPF you'd get fast and reliable failover and load balance if you wanted to.

You would need a capable router at either end though if your switches can't do it, which for gigE might not be all that cheap...
 
You don't need another box...

If you can do layer 3, as mentioned, then that's always the best option. Two point to point links, OSPF/ISIS.

If you can't and need layer 2 then your best option is probably LACP with some thoughtful configuration for backup links. After that whatever Extreme's version of RTG/protected link groups/flexlinks is called. After that EAPS (which isn't bad) and then, after carrier pigeons and possibly some other things, spanning tree.

Seriously, spanning tree has no place in a modern network, it's an abomination of a protocol (and the issue you've seen is a good demonstration of why - things like that happen too often...). I'd probably go for LACP as it's pretty robust and standards compliant.
 
This should not be a problem, i look after a network which has multiple links for redundancy and we also use EAPS and its great.
Are the links to the other sites connected in a loop for resilience e.g. a triangle ?
Or are you meaning two links from Site A to site B ?
If its two links from Site A to B then what bigredshark suggested and using shared ports with LACP is the best option.
 
We have had our network support guy in to look at this, there is something similar to EAPS that works over different media along the link so that should be beneficial for us.

Kimbie
 
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