Cisco Cisco Unified Customer Voice Portal 10.0(1)
4-9
Cisco Internet Service Node (ISN) Product Description
OL-1250-03
Chapter 4 VoIP Routing
Call Transfers and Outbound Routing
Call Transfers and Outbound Routing
This section examines initial call transfer from the ISN, specifically, how the NAM/ICM, ISN,
Gatekeeper, and Voice Gateways work together to perform H.323-based call transfer.
Gatekeeper, and Voice Gateways work together to perform H.323-based call transfer.
Note
Subsequent call transfers (such as agent initiated transfers), being similar to the examples described
below, are not discussed separately. One important difference, however, is that the
Call.NetworkTransferEnabled variable must be set to 1 in each script that contains network transfer
instructions.
below, are not discussed separately. One important difference, however, is that the
Call.NetworkTransferEnabled variable must be set to 1 in each script that contains network transfer
instructions.
Outpulse Transfer Mode
When the ISN receives the ICM/IVR message from the NAM/ICM, the ISN examines the initial two
characters in the Label field to determine the transfer mode. If the initial four characters are DTMF, then
the ISN will use outpulse transfer mode to transfer the call. Outpulse transfer mode instructs the ISN to
send the transfer information to the originating Voice Gateway, which will then outpulse the information
to the ingress leg of the call. This initiates the call transfer in an external telephony network.
characters in the Label field to determine the transfer mode. If the initial four characters are DTMF, then
the ISN will use outpulse transfer mode to transfer the call. Outpulse transfer mode instructs the ISN to
send the transfer information to the originating Voice Gateway, which will then outpulse the information
to the ingress leg of the call. This initiates the call transfer in an external telephony network.
Note
When the outpulse mode is used, the first two characters of the transfer information may be an attention
sequence for the telephony network, such as *8.
sequence for the telephony network, such as *8.
The ISN initiates the outpulse transfer by stripping off the DTMF characters from the Label field, and
sending the remaining transfer information to the originating Voice Gateway, using the call’s existing
H.245 control session. (The transfer information is passed in an H.245 userInputIndication message.)
sending the remaining transfer information to the originating Voice Gateway, using the call’s existing
H.245 control session. (The transfer information is passed in an H.245 userInputIndication message.)
Gatekeeper Configuration and Behavior, Outpulse Transfer
With outpulse transfer mode, the ISN communicates with the incoming Gateway, which already has an
H.245 control session for that particular call. Therefore, the ISN does not need to perform a lookup in
its assigned H.323 Gatekeeper, and can proceed directly with the transfer.
H.245 control session for that particular call. Therefore, the ISN does not need to perform a lookup in
its assigned H.323 Gatekeeper, and can proceed directly with the transfer.
Gateway Configuration and Behavior, Outpulse Transfer Mode
A Voice Gateway can provide access to a Time-Division Multiplexing (TDM) switching network; or it
can be connected to an ACD, PBX, or to one or more phones.
can be connected to an ACD, PBX, or to one or more phones.
In outpulse transfer mode, the originating Gateway receives transfer information from the ISN for a
particular call through H.245 messaging. The Gateway converts the transfer information to DTMF
signals and outpulses them to the call’s ingress TDM leg. From that point, the call transfer becomes the
responsibility of equipment on the TDM network.
particular call through H.245 messaging. The Gateway converts the transfer information to DTMF
signals and outpulses them to the call’s ingress TDM leg. From that point, the call transfer becomes the
responsibility of equipment on the TDM network.
Two things must happen for the Gateway to support relay of the H.245 information:
•
First, the Gateway must have been configured to support H.245 relay for that particular call. This is
done by adding an H245 relay command to the dial-peers that route inbound calls to the ISN. The
H245 relay command provides the option of choosing either the signal or alphanumeric methods
of relay. The signal option is recommended for use with the ISN.
done by adding an H245 relay command to the dial-peers that route inbound calls to the ISN. The
H245 relay command provides the option of choosing either the signal or alphanumeric methods
of relay. The signal option is recommended for use with the ISN.
•
Second, the ISN must indicate support for a compatible method of H245 relay during the H.245
capabilities exchange with the Gateway.
capabilities exchange with the Gateway.