I have a customer with multiple offices, each linked via VPNs between them using a mix of 2830 and 2860 routers. Each office has dual WAN's typically a FTTC used as a primary internet connection, and then a backup ADSL connection. This is configured in the load balancing.

Generally the inter office traffic works fine, but we do sometimes get voice quality issues with VoIP traffic between sites. I am trying to work out a way of resolving this. So either I would like to find a way to enable some kind of QoS facility for the VoIP, or perhaps better, configure it so that the backup ADSL connection (which is usually idle) can be used to handle VoIP traffic.

Any suggestions on ways to do this?

The normal QoS controls for VoIP seem to only apply to WAN traffic. Since our VoIP is contained entirely inside a VPN connection between the telephone PABXes at each site, I am not sure it can do this. (i.e. QoS can set aside bandwidth on a wan to allocate to the VPN, but I am not sure it can then give some traffic priority inside the VPN)

I could create a second VPN between sites, and specify that it connects over the other unused WAN interface, then use the load balancing to target a the named VPN. Anyone tried this?

Cheers,
John

I have a similar setup and have configured the QOS at each office to use the internal IP address of the actual PABX's rather than a UDP port number. I'm unsure why you think QOS only works over the WAN, have you read that somewhere?
e.g all traffic in and out for IP 192.168.1.4 (our MGI card in the PBX) gets top priority, saying as all voip traffic only stays within the LAN and the remote Lan via VPN's then I presume the QOS works as it should. Everything seems to be working ok but I've never found a way to actually test the QOS is doing what its supposed to be doing.

paulj48 wrote: I have a similar setup and have configured the QOS at each office to use the internal IP address of the actual PABX's rather than a UDP port number. I'm unsure why you think QOS only works over the WAN, have you read that somewhere?

No, not read anywhere specifically - perhaps it was just my reading too much into the options presented in the QoS config screens. Perhaps what was throwing me was that the QoS classes seem to only be associated with WAN1, 2 or 3, and there is no explicit option for saying "keep this amount of capacity free on this wan for a named VPN, and secondly, prioritise the data in the VPN so that someone's file transfer does not stomp all over the voip traffic". If it can wok all that out for itself that will make life much easier!

I can see I can create a named service type (say let's call it "Internal VoIP") which specifies the LAN IP of the other offices PBX. I can then attach that to one of the classes.

i.e. I can say reserve 30% of the capacity of WAN1 for class 1, where class 1 contains my "internal voip" rule. (presumably I would also need to make sure the WAN on which I am reserving the bandwidth is also the one carrying the VPN...)

paulj48 wrote: e.g all traffic in and out for IP 192.168.1.4 (our MGI card in the PBX) gets top priority, saying as all voip traffic only stays within the LAN and the remote Lan via VPN's then I presume the QOS works as it should. Everything seems to be working ok but I've never found a way to actually test the QOS is doing what its supposed to be doing.

Sounds like its worth a try, since if it works is far less complicated to configure than attempting to use the load balancing rules since that would need an extra VPN to each office configured into Trunk and all that extra complexity. I may be leading myself down a complex path by attempting to "make use" of the backup WAN when in reality just prioritising traffic on the primary WAN would actually do the job well enough.

Ta,
John