How can I better direct my network traffic using PVC routing?

April 7, 2007 2:21 AM

I'm looking for instruction on how to use the PVC routing table in my Linksys WAG54Gv2 router so that I can better prioritize network traffic.

There are a few users on my network that use YouTube frequently and it has a negative impact on the network.

Applications that require a constant yet smaller amount of bandwidth (i.e. World of Warcraft) seem to get blocked out when YouTube moves in.

Is there a way to work with my router that will allow for a reservation or prioritization of ~10kb/s of bandwith for real time applications.

Here is my current QoS Table configuration (which dosent really work.)

and Here is my PVC routing table (which i have no idea how to use.)


Thanks in advance.

posted by psyward to computers & internet (2 comments total)

PVC stands for Permanent Virtual Circuit (think point to point or VPN-like). It's really only useful for creating WAN interconnects*, so won't really solve your problem.

I'm not familiar with that particular router (although I could tell you how to do what you want with OpenBSD's pf), but doesn't WoW require more than the one port? Apart from that, what happens if you set HTTP to low priority? Are there any queue / priority options available under "Advanced QoS"?

(* Yes, it does get used at layer 2 or 3 as well, particularly on ADSL. In theory, you could have multiple PVCs - and multiple "connections" - on different PVCIDs over a single ADSL line. In practice, I don't think any ISP does that.)
posted by Pinback at 7:01 AM on April 7, 2007

HTTP, POP3, and SMTP should be low priority (and you shouldn't be permitting SMTP port 25 connections, period, unless you're actually running a mail server, to prevent computers on your network from becoming spambots). Looks like you'd also need to set port 6112 to high priority for WoW (I'm not a WoWhead).

But frankly, most home router's implementations of QoS are pretty broken. For one thing, traffic shaping under QoS doesn't really begin to do much in bursty traffic situations, or where there are continuing high bandwidth parallel streams, because the router may not properly manage ack bits on TCP connenctions, or may have no other strategy for handling communications with a host sending on UDP than to drop frames, there being not enough internal memory in these small, cheap devices to buffer them. For another, QoS in higher classes of service requires some cooperation between routers, which can't be guaranteed in public networks. YouTube uses Flash streaming, which is TCP based, so, in theory, by setting HTTP protocol to low priority, you are preferentially favoring your WoW ports, but whether you get much practical improvment as a result will be pretty iffy, I'd guess.

Shut off SMTP connections in your firewall rules, whatever you do, if you're not running a mail server. If you are, shut off SMTP everywhere but to the port forwarded server. In a Windows client network, you might try shutting off UDP altogether, too. Nothing really serious uses UDP, so you may find dropping all UDP packets at the router frees up some bandwidth.
posted by paulsc at 9:23 AM on April 7, 2007 [1 favorite]