[Asterisk-Users] Re: TDM400P digium card

[Alan Ferrency]

> Would QoS on a managed switch solve the ARP problem?

I'm not sure about QoS, because we haven't tried it, but my initial
feeling is "probably not." We solved our problem by separating the
network segments completely, which provides us with better security as
well as the quality we required.

I say "probably not" because it wasn't a case of the link segments being
saturated with ARP packets. There was plenty of overhead left to handle
the voice, on any particular segment a phone was on. This is not hard at
all, for ulaw over a 10MB link, for a single phone.

The problem was that the phones themselves seemed to be spending far too
much effort ignoring the ARP packets which didn't belong to them. The
symptom we saw was unreasonably high "decode latency" on the phone
status page (half a second or more, and not stable). Jitter and transit
latency measurements taken at the phone were not problems at all.

Alan Ferrency
pair Networks, Inc.
alan at pair.com


On Wed, 1 Mar 2006, mustardman29 wrote:

> Would QoS on a managed switch solve the ARP problem?
>
> > Regarding sound quality issues with Sipura SPA-841 phones...
<snip>
> > After that: Are your phones sharing the same network segments
> > as your non-VoIP ethernet data? Do you have a lot of ethernet
> > traffic? We found that even on a fully switched network, if
> > the SPA-841's received excessive ARP traffic (which is
> > broadcast to all switch segments, even though most other
> > network packets are suppressed), we had periodic "robot
> > voice" sound issues.