MGCP Back haul & FxO & CAS

[raja Saravanan]

Dear Friends,

When we configure FxO, FxS and T1 CAS in MGCP, how the gateway identifies and forwards the call signaling information to the call manager, please advise.

cheers,

Shaggy

[V.Naveen Kumar]

once call is hitting to gateway (MGCP) then their will be two signal q921 and q931.

where MGCP backhaul will be performed.

MGCP PRI backhaul is a method for transporting complete IP telephony signaling information from an ISDN PRI interface in an MGCP gateway to Cisco Unified Communications Manager using a highly reliable TCP connection.

[Jonathan Schulenberg]

Only iSDN PRIs have the backhaul component on TCP port 2428. T1 CAS, FXO, and FXS just use the normal MGCP signaling channel on TCP 2427. Specifically, CUCM will send a RQNT asking to be told when the line goes off-hook. The gateway will send a NTFY that it happened and then CUCM will RQNT for DTMF events until it has enough digits to route a call. At that point it sends a CRCX to start a call.

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[raja Saravanan]

Hi,

I have few more queries,

MGCP splits Media Translation ( done by the gateway ) and signalling ( done by call agent ).

In ISDN PRI D channel carries the call signalling information, by using PRI Backhaul, we send the call signalling information to the call manager.

When we use PRI backhaul, does the CRCX,MDCX,DLCX messages are not used for call setup and tear down.

How does MGCP identify the call signalling information when inband signalling is done like T1 CAS,FxO.

Please advise...

Cheers,

Shaggy