topic Re: Dual 7731 in Link Agg mode in ZoneDirector

Dual 7731 in Link Agg mode

scott_baker_612 — Wed, 20 Nov 2013 03:22:26 GMT

7731 Outdoor AP's in bridge mode. Is it possible to add a 2nd Pair and setup Link Agg/Trunking so we have 2 AP's on both roofs, to double the bandwidth?
Or will tis create a loop?

Re: Dual 7731 in Link Agg mode

primoz_marinsek — Wed, 20 Nov 2013 06:56:23 GMT

I'd say yes, but you'll need more than just 2 pair of 7731s. You'll also require a switch on both sides of the link to handle load-balancing and/or aggregation.

Re: Dual 7731 in Link Agg mode

robert_krause_6 — Wed, 04 Dec 2013 13:47:06 GMT

This is correct. Link aggregation is handled by intelligent switches (see LACP). In this sense, a pair of 7731 is just one link between two switches.

I would be more concerned about interference between the two pairs. Even when you choose lowest and highest channels. Does anybody have experience with such a configurartion? How far apart should the 7731s be at either end? 50cm, 1m, 5m?

Re: Dual 7731 in Link Agg mode

primoz_marinsek — Wed, 04 Dec 2013 14:19:14 GMT

At minimum I would put them 1m apart and at least 1 channel empty in between.

Re: Dual 7731 in Link Agg mode

scott_baker_612 — Wed, 04 Dec 2013 20:44:16 GMT

Thanks for the info, but i changed my design, so i don't need this setup.

Re: Dual 7731 in Link Agg mode

yew_heng_lee — Mon, 21 Jul 2014 14:18:50 GMT

I tried. One pair will in disable mode but failover is working if the active link is down. I test with peer to peer bandwidth test but the result showed the bandwidth not double up.

Re: Dual 7731 in Link Agg mode

robert_krause_1 — Thu, 24 Jul 2014 18:03:10 GMT

This is not surprising. The load balancing is done for end to end pairs, typically based on MAC addresses. When you measure between two machines, only one link will be used. Measure between a different pair of machines at the same time and you should see both getting the full bandwith of one link.

If you want to double the bandwith for a single communication pair, it gets much more complicated. You would need high speed routers on both ends to do packet based load balancing.