Voip flow traffic -ext call

[erinedison]

Hi All,

can someone please explain the below traffic,

SiteA(main site) SiteB(remote site)

CUCM cluster at SiteA

All external calls goes through SiteA SIP trunk,CUBE design at SiteA

scenario:

SiteB -ext calls(calls to mobile) >SiteB VoIP gateway router > MPLS > SiteA CUBE > SIP

or

SiteB -ext calls(calls to mobile) >SiteB VoIP gateway router > MPLS > SiteA CUCM > CUBE >SIP

I do understand ext.calls goes thro VoIP gateway,but when the traffic comes to SiteA,how will it know if its ext or int call,will CUCM decide,send to VoIP GW or the traffic hits the CUBE first,CUBE decides it as EXT call ?

Note:

I am new to VoIP,trying to learn the traffic

Thanks

Erin

[Jaime Valencia]

In CUCM you use route patterns to send calls outside of CUCM, I suggest you read the dial plan chapter from the SRND to understand call routing in CUCM.

Simply put, depending on the digits you deliver to CUCM, it will match a a DN or pattern, and upon that, it will know what to do, depending on what you configure. Either it will match something that exists within CUCM,  or it will need to be routed outside CUCM.

As for CUBEs, you usually don't find devices registered to them, they just work to route calls between two entities, CUCM's, PBXs, to PSTN, etc. and route based on the destination-pattern configuration, which is analog to the route patterns in CUCM. You'll match one based on the digits you send, and it will send the call to wherever it's needed.

[erinedison]

Thanks for the explanation Jaime.

my doubt is:

once the voip traffic enter SiteA,which is its first point of contact  ?-CUBE or CUCM

Thanks in Advance

Erin

[Terry Cheema · Accepted solution]

As Jaime has explained above - its the CUCM who decides where to send the call. Whenever any phone anywhere in your network dials a number, the digits are sent to the call manager, which will make the call routing decision - if its an internal number - it will ring the internal phone, if its external number it will send to the gateway (or CUBE).

CUCM always handles signalling and directs RTP media flow directly between the end points. In your query if someone dials an external number, your CUCM will handle the signalling, so the signalling traffic will be between the end point and CUCM and will direct media directly to the gateway (which is CUBE in this case).

Let us know if you have more questions.

-Terry

[erinedison]

Thanks everyone for the great explanation

Erin

[CSCO11470555]

Hi Terry,

I have a doubt about what you said and I would like to clarify it. When the call is established, is the RTP traffic between, for instance, Cisco IP phone which is behind CUCM and external mobile number (in the PSTN) handled by CUCM or this traffic is sending directly between the endpoints?

Thanks in advance.

Kind regards,

[Charles Hill · Accepted solution]

Just to add to what has already been stated;

Dialed number analyzer is a great tool to test a dial plan and verify how the call is routed or blocked.  It will show the matched route pattern, calling search space, route group, etc.....

Great tool!

Link below discusses Dialed Number Analyzer.

http://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/dna/10_0_1/CUCM_BK_C385AEC0_00_cucm-dialed-number-analyzer-100/CUCM_BK_C385AEC0_00_cucm-dialed-number-analyzer-100_chapter_01.html

Hope this helps,

Please rate helpful answers.

Thanks.