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B2B incoming call not working ::

one of my client site has 3 meeting room with SX20. SX20s are registered with CUCM.


if somebody calls from internet it should reach SX20  that is internally registered with CUCM .



Im able to make outbound video call without any issue. But incoming call not working. I can see call reaching both EXP E and Exp C.


In this setup they dont have any internal DNS server. So EXP C is pointing to the same DNS of EXP E external DNS say thats the problem now.


Is that the reason incoming call not working for it? is it a must EXP C should be pointed to DNS server? how can i do this set  up without internal DNS server... 


They want B2B setup ...



Accepted Solutions

Re: B2B incoming call not working ::

Also confirm you have a css on the sip trunk with access to your pattern.
VIP Advisor

Re: B2B incoming call not working ::

All of your devices should have proper DNS server settings on them, whether they be internal DNS servers (dedicated, a windows domain controller, a router, etc) or an external one (such as the google server), but this is only used to resolve domain names to IP addresses (usually for outbound call routing).

For your troubleshooting, I'd suggest you go back through the Deployment Guide and check that against your installation and see if you can find the steps that were missed (which are quite likely to the the DNS SRV records in the Internet wherever your domain name is hosted).

If both your end, and theirs, both are using Expressways, you could create a qucik and nasty B2B connection using a Neighbour Zone without the need for DNS SRV entries, and just use the Search Rules to route calls between the two.

Please remember to rate responses and to mark your question as answered if appropriate.

Re: B2B incoming call not working ::

i clearly mentioned that i can have outbound call without any issue ie to the internet.

inbound call is the issue. if there is SRV record the calls are reaching till EXpressway C. ? i can see that from history.
But it ends up host not found 404.

i followed the guide. it such a simple setup i dont know why there is no simple example for this for whole setup. i followed cisco CVD guide it failed both inbound and outbound call...

Re: B2B incoming call not working ::


Where these Sx20s are registered?
If the calls are reaching to expressway C then i think you need to make proper search rules to route the calls to endpoints.
DNS will not come in picture until you will not routing calls to DNS zone or using any SRV.
And for that i think your Expressway E will play a role.

Suppose you are dialing from outside then to reach your expressway E you need SRV _sip or _h323 and A record for your Expressway E.
Once the call reaches to your expressway E it will use some search rule and then route the call to Expressway-C

Now on Expressway C you just need a proper search rule to route the call to endpoint DNS not needed there.
Your B2B calls will work properly without any issues.

But yes as per deployment guides you need to have proper DNS configured on both to avoid any issues.




Please rate if it is helpful....


Re: B2B incoming call not working ::

i understood this is the way it should work.

SX20 is registered with CUCM. if outside parities dialing as you told i can see it reaches till Expressway C. then it say host not found 404.

can you please give a simple example for expressway C and express E search rule and transform for incoming call from internet.

do i need to setup URI in directory number of SX20? i did that one also still result is same.

Re: B2B incoming call not working ::

On the expressway c go to Status> Search History and look at the call attempt, it will tell you where it is trying to route the call and maybe some helpful information.

Re: B2B incoming call not working ::

i can see that from search history... it showing it going to CUCM. but ends up host not found 404.

Re: B2B incoming call not working ::



So in search history you are seeing that call is routed to CUCM successfully?

If yes then you need to check what pattern its sending to CUCM and whether that is there in CUCM or not.

So suppose from outside you dialed and call reaches to Exp-C and on CUCM you have directory numbers with 1xxx only then you need to make a search rule on Exp-C  which matches the (.*) and replaces it to (\1) and then the target neighbor zone to CUCM.


So it should match with CUCM directory numbers and call will work.



Please rate if it is helpful..

Re: B2B incoming call not working ::

Also confirm you have a css on the sip trunk with access to your pattern.

Re: B2B incoming call not working ::

oh  i really missed CSS in "inbound calls" section of SIP trunk . let me see now what happens.


Re: B2B incoming call not working ::

After assinging CSS in inbound call im now able to establish call for incoming call . but im still unable to get audio or video. it looks like firewall issue still.

Re: B2B incoming call not working ::

i tried this already but ended up with following in Expressway C

416 Unsupported URI Scheme

why its like that?
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