7941G Not Following Dialplan

[papkee]

Hi all!

I've got a strange problem with a 7941G that I'm trying to figure out. I have a small personal SIP system with about ten or so phones, and this is the first 79x1 series phone I've tried to work with (the others are 79x0 and 79x2 series phones)

For whatever reason, although it registers fine with the PBX and I can see the dialplan.xml being sent to the phone on the tftp server, when I dial an extension (for example, 197) the phone just sits there expecting more input. If it sits long enough, it ends with the unavailable tone and "reorder" on the screen. The same extension dialed on my 7942 works fine and calls right away, and the dialplan.xml is the same used for both. I will also mention incoming calls to the problem phone work with no issues.

My dialplan.xml is as follows:

<DIALTEMPLATE>
<TEMPLATE MATCH="0.." TIMEOUT="0"/>
<TEMPLATE MATCH="1.." TIMEOUT="0"/>
<TEMPLATE MATCH="\*.." TIMEOUT="0"/>
<TEMPLATE MATCH="91.........." TIMEOUT="0"/>
<TEMPLATE MATCH="9.........." TIMEOUT="0"/>
<TEMPLATE MATCH="72.." TIMEOUT="0"/>
</DIALTEMPLATE>

I can also post sanitized phone config xmls if they're needed as well. Is the dialplan format different between the 7942 and the 7941, or is something else going on here?

Thanks!

[Leo Laohoo]

Dial plan looks good.
What firmware is this problematic phone running on?

[papkee]

Running on the latest available SIP firmware: 9-4-2SR3-1

I've got a second 7941 now exhibiting the same issues. I ran a couple TCP dumps comparing a working phone to a non-working phone, and it seems like it could possibly be a network issue somewhere else in the path. On a working 7942, we see the following when a call is dialed:

00:34:05.260489 IP xx.yy.zz.12.51740 > xx.yy.zz.10.5160: UDP, length 345
00:34:05.265641 IP xx.yy.zz.12.51237 > xx.yy.zz.10.5160: UDP, bad length 1511 > 1352
00:34:05.265673 IP xx.yy.zz.12 > xx.yy.zz.10: udp
00:34:05.265685 IP xx.yy.zz.12 > xx.yy.zz.10: udp
00:34:05.269977 IP xx.yy.zz.10.5160 > xx.yy.zz.12.sip: SIP: SIP/2.0 100 Trying
00:34:05.293710 IP xx.yy.zz.10.5160 > xx.yy.zz.12.sip: SIP: SIP/2.0 200 OK
00:34:05.356801 IP xx.yy.zz.12.21676 > xx.yy.zz.10.10366: UDP, length 172
00:34:05.376856 IP xx.yy.zz.12.21676 > xx.yy.zz.10.10366: UDP, length 172

it continues these small UDP packets while the call is in progress

Then on one of the "problem child" 7941's:

05:33:44.172451 IP xx.yy.zz.86.52270 > xx.yy.zz.10.5160: UDP, length 370
05:33:44.185620 IP xx.yy.zz.86.52318 > xx.yy.zz.10.5160: UDP, bad length 1496 > 1352
05:33:44.186785 IP xx.yy.zz.86 > xx.yy.zz.10: udp
05:33:44.675734 IP xx.yy.zz.86.52318 > xx.yy.zz.10.5160: UDP, bad length 1496 > 1352
05:33:44.676676 IP xx.yy.zz.86 > xx.yy.zz.10: udp
05:33:45.675730 IP xx.yy.zz.86.52318 > xx.yy.zz.10.5160: UDP, bad length 1496 > 1352
05:33:45.676668 IP xx.yy.zz.86 > xx.yy.zz..10: udp

It never "dials" on the phone and just continuously sends those 1496 packets. On the PBX side I never see anything past the first packet (length 370) unlike the 7942 which sends a continuous stream once the connection has been made. If I were a betting man I'd say those bad length packets are the issue, but I'm not sure why that doesn't affect the 7942 as well.

Another important fact is that all these phones are connected back to the PBX via VPN tunnels. I know that's typically a bad setup for SIP configurations but besides these two phones every other client has been working flawlessly, so I'd be inclined to say it's not the issue at hand. Tomorrow I will try and directly connect the phones without a VPN and see if the same issue persists.

[Leo Laohoo]

If they connect back to a VPN tunnel then take a phone where there is no VPN and see if the dialplan works or not.

[papkee]

Without the VPN in the middle the phone appears to work normally. Interesting.

I still can't figure out what's going wrong. It seems like the bad packet length is the cause but do the 7941 series of phones not support packet fragmentation? I use this same VPN setup with 7960's and 7942's with no issues.

[HARIS_HUSSAIN]

Try changing the Firmware of the Phone