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SBC not re-writing NOTIFY packets

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carolinainnovative

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Hello folks! Anyone seen any issues getting BLF/Presence updates on a yealink phone (T46G - 28.71.0.176) when going through the SBC?

My Shared park and blf buttons all show with little red Xs in them.

They work for dialing - just not for presence, pickup, etc.

I haven't wiresharked it yet or anything - just thought someone might have seen it already.
 
Re: 3cx SBC with presence & Yealink

So SBC - meaning this is a cloud installation?
 
Re: 3cx SBC with presence & Yealink

Yes, it is. v12 cloud rc1/sp4.
 
Re: 3cx SBC with presence & Yealink

I recall something like this for a remote phone with an older Yealink firmware but it is not a cloud installation. It is on premise and is no longer an issue.
 
Re: 3cx SBC with presence & Yealink

Oooooook so anyone else?

I'm having this issue with Grandstream and Yealink phones - no BLFs when using the SBC.

They are being PROGRAMMED in the phone - I can verify that on the web interface - but perhaps the subscribes aren't working properly?

Anyone seen this?

And before someone mentions it - yes, I modified the Grandstream template to use SBC. But it isn't _just_ grandstream. Having same issue with Yealink as well.

I can SEE the sip SUBSCRIBE messages in my tunnel log on the remote end.

Honestly I can't find the tunnel log on the server end. It isn't in the log files folder, so I can't see what is coming back, but the sip SUBSCRIBE looks fine. See here:
Code:
SUBSCRIBE sip:[email protected]:5060;user=proxy SIP/2.0
Via: SIP/2.0/UDP 10.254.0.50:5060;branch=z9hG4bK493901591;rport=5060
Max-Forwards: 70
Route: <sip:172.20.1.31:5060>;lr
Contact: <sip:[email protected]:5060;user=phone>
To: <sip:[email protected]:5060>;tag=1a6ac76f
From: <sip:[email protected]:5060;user=phone>;tag=988243711
Call-ID: [email protected]
CSeq: 20053 SUBSCRIBE
Expires: 120
Accept: application/dialog-info+xml, multipart/related, application/rlmi+xml
Allow: INVITE, ACK, OPTIONS, CANCEL, BYE, SUBSCRIBE, NOTIFY, INFO, REFER, UPDATE, MESSAGE
Supported: replaces, path, timer, eventlist
User-Agent: Grandstream GXP2120 1.0.5.32
Event: dialog
X-Grandstream-PBX: true
Content-Length: 0
 
Re: 3cx SBC with presence & Yealink

Can you run wire shark on the server?
 
Re: 3cx SBC with presence & Yealink

I can, and I have, but wiresharking SBC connections is not terribly interesting, as I can't see what is actually going on between the tunnel and 3cx.

I see the subscribe come in, I see a 200-ok go out, and then later I see a notify go out saying the subscription was terminated due to timeout... but that is all on the "outbound" side of the tunnel. I can get the same information from the tunnel logs on the remote end of the sbc...

What I (think I) need is logs of what is going on inside 3cx with those subscriptions. The SUBSCRIBES all look well formed, with proper VIA routes, etc. So - in theory, 3cx should be forwarding me those notifications. It is not.
 
Oooooooooooooooooooooook -

So here we are... I have done some more investigation and found that despite the wireshark results on the phone system itself, the NOTIFYs ARE being transmitted, as they are being spit out of the remote SBC and being sent to the phone.

Here's the problem methinks - the SBC isn't actually re-writing the FROM: line of the NOTIFYs,

"Why should it re-write NOTIFYs?" you ask. It doesn't have to re-write INVITEs! It just adds appropriate VIA tags!

Ah, yes, you are correct.

However - when it SUBSCRIBEd to the event, to whom did it subscribe? Who is the registrar-of-record for SBC connections? THE SBC. It is expecting NOTIFYs FROM THE SBC.

Polycom, strangely enough, doesn't seem to give a damn. Yealink and Grandstream both seem to be quite picky about it.

They want their NOTIFYs to come from their registrar of record - or at least the entity to whom it sent the subscribe.

Any thoughts on a fix?
(also changed the title of the original post to properly reflect the actual issue)
 
Craig, why would I email Yealink support? This isn't just a yealink problem. This seems to be a problem with the 3cx SBC. I do plan to email 3cx support here shortly, but I was really hoping that someone else had seen this problem, too, so I'd have more evidence to point at with support.

lets see if anyone else has seen this.....
 
Reply from 3cx support -

"It is a KNOWN ISSUE with the SBC. That's why it is in RC."

As long as they're aware of the issue, I'm happy.
 
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