Bonding 4 NICs


I plan to build a high-capacity FreePBX Distro-based IP-PBX to replace an aging Elastix installation and I want to install bonding for a quad-port gigabit-NIC to increase reliability and bandwidth. I am unclear as to which bonding mode will work best…

mode=1 (active-backup)
mode=2 (balance-xor)
mode=3 (broadcast)
mode=4 (802.3ad)
mode=5 (balance-tlb)
mode=6 (balance-alb)

Any advice?


Seriously, 4G of traffic on one box? That’s over 3000 concurrent calls and would be, by orders of magnitude the busiest FreePBX system in the world.

It is more about the fault-tolerant connection than the bandwidth. We currently run up to 260 concurrent channels on our existing system and I fully expect to at least double that traffic on a routine basis in the near future. I need rock solid performance–this is why I am asking. (Plus, I have a bunch of Pro/1000 quad cards in stock.)

You are basically bound by what router/switch is at the other end of your bonded connection use what you can but choose a topology that is transparently redundant at both ends, each uncompressed g711 channel will take roughly 80kps each way, so Gbit is nice but not a limitation, your limitation is your need for an unimpeachable upstream bandwith which needs to be by your metrics at least 50Mbs uncompressed.

For “rock solid”, I suggest you look at a SIP proxy between your VSP’s and your asterisk box as you are approaching the limits of Asterisk as a B2BUA and the last thing that will fail is your network card(s).