Cisco ISDN GW with VCS Control

[Acevirgil de Ocampo]

Hi Experts,

I am new with Cisco ISDN Gateway 3200 and i will be integrating it to the existing video network manage by VCS Control with endpoints and MCU registered as SIP.

Here's a sample dial plan on existing video network:

Endpoint SIP URI: 51xxxxx@vcs.domain.com

MCU SIP URI: 53xxxxx@vcs.domain.com

ISDN GW H323 alias: 54xxxxx

I came up with these questions:

1. For us to intergate the ISDN GW on the video network, we need to register it as H323 on the VCS right?

2. For call scenario like from a SIP endpoint or MCU calling an ISDN endpoint via video, how's the call flow? Do the SIP endpoint/MCU registered as SIP on the VCS can dial directly on that ISDN endpoint? Or they will dial first the H323 number of the ISDN GW registered on the VCS then routed to an auto attendant of the ISDN GW?

3. How about from ISDN endpoint to SIP endpoint?

Please send me a sample guide and configuration on the ISDN GW and VCS on how we can make the call flow work base on the call scenarios mentioned.

SIP -----> ISDN

ISDN ------> SIP

Thank you for the help.

Best regards,

Acevirgil

[Paulo Souza · Accepted solution]

Hi,

1. For us to intergate the ISDN GW on the video network, we need to register it as H323 on the VCS right?

Yes, that is right. That's not the only method, but it is the most used and easier way. I suggest you to use it.

2. For call scenario like from a SIP endpoint or MCU calling an ISDN endpoint via video, how's the call flow? Do the SIP endpoint/MCU registered as SIP on the VCS can dial directly on that ISDN endpoint? Or they will dial first the H323 number of the ISDN GW registered on the VCS then routed to an auto attendant of the ISDN GW?

In this case, you have to interwork the call in VCS. Any SIP endpoint can dial ISDN numbers, then VCS will route the call to the gateway in h323 format, only the number with no "@domain.com" and the call will be interworked. The flow would be something like this:

SIP Endpoint -------[sip]---------> VCS --------[H323]----------> Gateway ISDN

3. How about from ISDN endpoint to SIP endpoint?

The same concept is applied. ISDN gateway sends the call in H323 to VCS, and VCS interwoks the call and send SIP to the endpoint. Something like this:

SIP Endpoint <-------[sip]--------- VCS <--------[H323]---------- Gateway ISDN

With regards incoming calls from ISDN gateway to VCS, there is an important thing to be considered. You basicly have to methods:

• You can configure ISDN gateway to route calls to the auto attendant, then users will be able re-dial to your internal endpoint numbers from the auto attendant
• You can configure ISDN gateway to use DID (Direct inward dialling), in this case, you create routes in the gateway that maps each ISDN number to a internal endpoint registered to VCS

Both methods work fine, however, when using auto attendant it is very important to implement a toll fraud prevention schema. Take a look at this thread:

https://supportforums.cisco.com/message/3971947#3971947

With regards the guide, there is no a simple one explaining step to step, but the admin guide brings a nice explanation on how to configure dial plan in the gateway and how to register the gateway to VCS. Check out this guide:

http://www.cisco.com/en/US/docs/telepresence/infrastructure/isdn_gw/admin_guide/isdn_gateway_printable_help_2-2.pdf

I hope this help.

Regards

Paulo Souza

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[Acevirgil de Ocampo]

Hi Paulo,

Thank you so much for your answer and very clear explanation.

I'll be deploying one ISDN GW for the customer and 'ill let you know how it goes.

Thanks you!

Best regards,

Acevirgil

[Paulo Souza]

You are welcome!

Paulo Souza

Was my response helpful? Please rate useful replies and remember to mark any solved questions as "answered".