[Asterisk-Users] ADSI phone vs. IP phone (and proper implementation thereof)

[daryl at introspect.net]

> -----Original Message-----
> From: asterisk-users-admin at lists.digium.com 
> [mailto:asterisk-users-admin at lists.digium.com] On Behalf Of 
> Ray Burkholder
> Sent: Monday, January 19, 2004 7:38 PM
> To: asterisk-users at lists.digium.com
> Subject: RE: [Asterisk-Users] ADSI phone vs. IP phone (and 
> proper implementation thereof)
> 
> 
[...]

> I'm wondering if what you say is actually true.  According to 
> recent media 
> releases, Cisco has shipped over 2 million of their IP 
> phones.  They must be 
> doing something right.
[...]

Yes, they are marketing well, and the phones work just fine.  But what
does the number of units shipped have to do with anything?  I've got a
dump truck load of 1721/VPN-K9s with ADSL cards that STILL have an open
bug after almost six months (which causes blocking on the ATM port,
rendering the router unable to pass traffic).  Does that mean they are
perfect?  No.

I'd go as far as saying that the 7960s are better than that, as they
work very well.  Until you try to use the built in switch and hit the
right conditions.

[...]
> Voip quality is not necessarily about bandwidth (because it 
> works on T1 data 
> lines as well as GB ports), but about instantaneous 
> bottlenecks in the 
> network.  These instantaneous and random bottlenecks can 
> occur in the cad 
> environment mentioned.  But with appropriate COS (layer 2) 
> and TOS (layer 3) 
> settings in the phones, switches, and routers, these 
> bottlenecks become non- issues.
[...]

That's VoIP 101.

The real issue is that the phones crash/reboot/degrade under high pps on
the switch.  Probably because of all of that processing for VLANS and
switching taking place on the same processor as the phone (just a guess,
I have no idea of the internal design).

Go get yourself a nachi-style worm, or other high-pps type app and put
it on a reasonable well-powered machine on a 7960.  Crank up the packets
and try to make phone calls.  Then we'll talk again.

Daryl G. Jurbala
BMPC Network Operations
Tel (NY): +1 917 477 0468 x235
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