R2511-HP MSR Router Series Voice Configuration Guide(V5)

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Figure 100 Protocols and standards that VoFR complies with
Call flow in dynamic mode
The following shows the call flow in the dynamic mode:
1. The calling party picks up the phone. The voice interface card detects the off-hook action, plays
dial tones to the calling party, and waits for the calling party to dial a number.
2. The calling party dials and the voice interface card collects and stores the dialed digits, that is, the
called number.
3. Upon the completion of dialing, the voice gateway matches the called number against voice
entities.
4. VoFR processes the call if a VoFR entity is matched. The processing method depends on the call
mode configured for the VoFR entity.
5. In the dynamic mode, signaling exchange occurs between the calling and called sides until the call
setup succeeds or fails. This process also involves voice codec negotiation and bandwidth request.
The FR-supported voice gateway on the originating side requests the frame relay to establish a
voice channel according to the outbound interface of the VoFR entity, and the frame relay
dynamically allocates an FRF.11 sub-channel to the voice channel.
6. After the call setup succeeds, both the calling and called parties can communicate with each other.
Call flow in FRF.11 trunk mode
The call flow in the FRF.11 trunk mode differs from that in the dynamic mode. In the FRF trunk mode, once
a voice channel is set up, this channel remains until it is manually cleared. An FRF.11 trunk call directly
uses the established voice channel, and the FR-supported voice gateway on the originating side requests
the frame relay to establish any additional voice channel when the calling party originates a call.
Therefore, the PVC IDs and FRF.11 sub-channel IDs at both ends of the trunk must be the same in the FRF.11
trunk mode.
No signaling exchange is involved in FRF.11 trunk mode. The following shows the call flow in the FRF.11
trunk mode, with the first four steps being the same as those in the dynamic mode:
1. The calling party picks up the phone. The voice interface card detects the off-hook action, plays
dial tones to the calling party, and waits for the calling party to dial a number.