[asterisk-users] Re: Best inexpensive home office router for VoIP(QoS with maybe PoE)

[Brad Templeton]

On Fri, Jan 05, 2007 at 05:37:22PM -0500, Allen Casteran wrote:
> Mike wrote:
> >You're quite right, I typed before thinking.  Upload is the problem 
> >anyways, since it usually (in homes) uses much more limited bandwidth 
> >than downloading does.
> > 
> >No answer to my question though: How do you people handle QoS without 
> >relying on the phones to do that?  I'd like a box that can be purchased 
> >and installed easily (Linksys type of product)
> > 
> 
> Mike,
> 
> Unless your ISP specifically supports QOS on your internet connection 
> there is NO QOS beyond your router. Only within your network will the 
> QOS be effective. Once the packets go through your router all control is 
> lost. :)
> 
> This also means that you have little control over the priority of the 
> traffic coming through the router's WAN port. The most you could do with 
> QOS in this case is to limit outbound traffic from your PC if it would 
> interfere with a voice call. The same is not true for the return (ie 
> inbound) packets.


True, but for many people the upstream path is the biggest, and sometimes
the only bottleneck in their internet traffic, especially to a good
termination provider that has not underprovisioned.   So this is
the one place QoS can make a difference.

For downstream, it can be an issue.  Though in theory a clever
router can notice the amount of high-priority RTP traffic that is
going through, and then cause incoming TCP traffic to back off
to leave room for the RTP traffic.   I don't know if the cheap
boxes do this.   The D-link DI-102 qos box literature seems
to talk mostly about upstream so I don't think it does this.

On the other hand, I tested my wrt54g with qos firmware on,
and while downloading at full speed I detected no dropped packets
in incoming voice, so perhaps it does that.