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New Member

Problems calling accounts from H.323 endpoints

Hi folks


We're trying to get to the bottom of an issue our organisation has with trying to place calls from H.323 endpoints to accounts.


During some fairly extensive testing we discovered that some of our H.323 endpoints are able to call addresses without issue, but others fail with a cause code of 127 (interworking).


Initially there appeared to be little logic to why the calls were failing, as the were passing through our VCS and VCSX correctly: the interworking issue appears to be at the end.


Further testing seems to indicate that the issue is connected to the length of the H.323 system's H.323 ID, with anything longer than 32 characters causing the call to a address to fail.


Systems that have an H.323 ID of 32 characters, or shorter, seem to be able to call addresses reliably, and shortening the name on a system with a longer H.323 ID causes it to begin working.


We were wondering if there's a known issue with not accepting incoming H.323 calls from devices with long H.323 IDs that causes the interworking to fail on the servers?


The naming strategy we use internally was chosen to be logical to our customers and as a result will be difficult to alter to retain meaningful names that are less than 32 characters, so we'd like to find a workaround that will allow us to place H.323 calls to addresses.


Two options have been suggested so far:


  1. Remove the H.323 ID entirely
  2. Shorten the H.323 ID to 32 characters or less


Unfortunately neither option is ideal, as we use the H.323 IDs internally for diagnostics, billing etc


One alternative I would like to try and implement is a hybrid transform/rule/CPL our VCS on the outbound call to remove/replace the H.323 ID with something shorter; a rule that only affects outbound calls to addresses, whilst leaving the H.323 ID intact for all internal and other external calls.


Unfortunately it doesn't appear to be possible to effectively spoof the internal H.323 ID when placing a outbound call through a VCS.


I'd like to know if anyone else has suffered similar issues placing calls H.323 calls to addresses from endpoints with long H.323 IDs?


Is this a general issue with H.323 to SIP calls, or does it just affect calls to addresses?


If either of the above has been an issue what solutions have you come up with?


Unfortunately our organisation does not currently accept inbound calls, otherwise we would simply request that the user call in to us, which I assume would resolve this issue.


Ultimately we are planning migrating to Jabber Guest, which we're sure will resolve this issue.


However, in the mean time we would like to offer a solution/work around which will mean reliable and consistent calls from any of our H.323 endpoints to a address.


Thanks in advance for your input and advice.



Everyone's tags (1)

Accepted Solutions
VIP Purple

Just found this while I was

Just found this while I was looking for something else, it explains an limitation with Jabber Video and long video addresses.


VIP Purple

Where are the endpoints

I've seen something similar in our environment where when we try to dial an H323 endpoint from a SIP endpoint that is outside of our network, and interworking fails.  This is because by default, interworking is configured on the VCS for endpoints that are registered to it.  We had to change our Expressway interworking to be always on no matter where the endpoint is registered, this would allow interworking on the Expressway to external endpoints despite the protocol used in the local environment.  Might work for you.

New Member

Hi PatrickThanks for that.We

Hi Patrick

Thanks for that.

We've done some experimenting using zones this afternoon in order to force interworking on for an call from an internal H.323 device to a address and unfortunately it still fails when the H.323 ID his longer than 32 characters.


VIP Purple

I was thinking it was

I was thinking it was interworking because that's what the error you first mentioned - cause code of 127 (interworking).

With the link I posted in my other comment, it sounds like you'll have to lower your character amount for the H323 endpoints.

VIP Purple

Just found this while I was

Just found this while I was looking for something else, it explains an limitation with Jabber Video and long video addresses.


New Member

That's a very interesting

That's a very interesting article, and our testing seems to bear out what it says, although the limit for the H.323 ID seems to be 32, rather than 31 characters.

We're still trying to identify if this limit *only* affects H.323 to calls, or whether it also affects *all* H.323 to SIP calls.

VIP Purple

Yeah, it was in the Jabber

Yeah, it was in the Jabber Video section of the forums, but it seems very similar to your issue, figured I'd point it out.

New Member

I think it absolutely hits

I think it absolutely hits the nail on the head - we just have to figure out the best way to work around it now: either shortening/removing all the H.323 IDs or registering all the endpoints as SIP.