I just attached an Avaya model 9620 phone to my Astlinux system using firmware 2.0.1.34. MWI worked immediately without any messing around.

I've recently starting having disconnects on my Avaya 4610SW phone with Asterisk which I've tentatively attributed to the density of WiFi networks in my neighborhood. I've been seeing articles about WiFi density leading to spontaneously lost connections. I have no idea if this is really the problem BUT I decided as an experiment to move my Asterisk server and my 4610SW over to a HomePlug network of Netgear Powerline bridges, and bridge the Homeplug network with the WiFi router via it's built-in Ethernet switch.

I had to disable 802.1Q on the phone from its default setting of "auto" as the bridging of HomePlug to WiFi apparently made the network look like two different VLANs. The phone booted off the same server just fine, but could not SIP register until I set 802.1Q to "off".

Another plus: there was I'm guessing enough latency on the WiFi network that the echo canceller in the 4610SW couldn't handle it and I got some echo that only I could hear on a call, so I lived with it. With HomePlug, the echo canceller trains in a second or two and it sounds a lot better. No idea if HomePlug is going to solve my disconnect problem, but so far so good.

HomePlug is an industry standard for running Ethernet over household electrical wiring at around 30Mb/s. I used Netgear but such stuff is also made by LinkSys etc. My Asterisk server is in the basement, the router on the first floor, and phone in my office on the second floor, and so far it all works great with HomePlug. I have a long meandering blog article about it at

http://coverclock.blogspot.com/2007/02/asterisk-wifi-homeplug-and-avaya-sip.html

but this is the gist of it.

XO Communications holds the capitol on new Avaya systems- including the network side (voice and data) for 35+ users- if you need a new system, let me know. Jon.Evans@xo.com.

Just a quick follow up: current thinking on this issue with Asterisk and my Avaya 4610 phone is that
Asterisk is sending an unsolicited notification regarding the state of the message waiting lamp, which
I'm told is not SIP standards compliant. In my copious free time I'll try once again to get an Ethereal
trace to verify this.

Still, commenting out the "mailbox=" line in your sip.conf file is a quick, effective workaround. If, like
me, your hearing is not what it should be (or might have been, twenty-five years ago), the 4610 (and I'd
guess, the other 46xx phones too) has the features you really need: sound quality, great speakerphone
(something you don't appreciate until you use a lousy one), and a headphone jack that'll take a good two-ear
(Plantronics in my case) headset (makes a huge difference in my ability to hear the other party).

-- John "Soon to be part of the geriatric generation" Sloan
   http://www.diag.com

When we last left our hero, he was trying to get an Avaya 4610
SIP phone to work reliably with his Asterisk server. The phone
would stop communicating with Asterisk after a few hours, and
could only be fixed by rebooting. Ethereal traces of both this
phone and SIP soft phones (which worked) during the same
test period were too detailed to be very useful, but no obviously
smoking gun turned up.

On 2006-02-03 I came across a bug report for an Avaya 4602 phone
used with Asterisk that had a similar but not identical problem.
The workaround was to comment out the "mailbox=" line in the
Asterisk /etc/asterisk/sip.conf file for the Avaya phone, disabling
the updating of the messaging waiting indication on the phone.

Since making this change several days ago, my 4610 has worked just
fine. Your mileage may vary. Although expensive, the 4610 has the
features I really need: great sound quality, a great speaker phone,
and a headset jack.

http://secunia.com/advisories/13721/

Avaya now has more phones, including one with a colour screen.
http://www1.avaya.com/enterprise/telephones/4600/product_details.html