User Manual - Configuration Guide (Volume 3)

Chapter 1

Versatile Routing Platform

VoIP Configuration

feedback, the application system can adapt to different network environment. The feedback on the quality of transmission is also helpful for the fault location and diagnosis.

 

 

 

H.323 Protocol stack

 

 

Data

Signaling

Audio

Video

 

 

 

 

 

 

 

 

T.126

 

T.127

 

 

 

G.711

H.261

 

 

 

H.245

 

G.729

T.324

 

 

G.723.1

H.263

 

 

 

H.225.0

 

T.124, T.125

 

G.723.A

 

RAS

 

 

T.123

 

 

 

RTP, RTCP

 

 

 

 

 

 

 

 

 

 

TCP

 

 

 

UDP

 

 

 

 

 

 

 

 

 

 

 

 

Network Layer

 

 

 

 

 

 

 

 

 

 

 

 

 

Link Layer

 

 

 

 

 

 

 

 

 

 

 

 

Physical Layer

 

 

 

 

 

 

 

 

 

Figure VC-1-3H.323 protocol stack

III. A typical telephone call processing by VoIP

Before configuring the voice function for router, please firstly learn the relevant flow of the Application Program Layer for the smooth configuration.

1)User picks up the hook and the voice interface board detects the action. Then the board transmits this signal to the VoIP signal processing part over the router.

2)The VoIP Session Application Program plays the dialing tone and waits for the user to dial.

3)The user begins to dial, and the VoIP session application program collects and stores the dialed number.

4)After collecting enough number to match a configured destination mode, the number will be mapped to an IP host through a dial plan mapper. The IP host directly connects with the target telephone or the PBX. If the PBX is connected, PBX will accomplish the remaining part of the call.

5)The VoIP session application program uses the H.323 protocol to transmit and receive voice data channel for the connection in each direction over the IP network. If the PBX is to processes a call, it will forward the call to the destination telephone.

6)The agreed codec mode is enabled at both ends of connection, which uses the RTP/UDP/IP as protocol stack to continue the session.

7)Once the end-to-end RTP voice channel is established, the prompt signals of all the calling procedures and the signals that can be transmitted in the band are transported through this channel over the IP network. RTCP packet is used to transmit such information as the transmission quality of voice data in the calling session.

8)When one calling party is on-hook, the session ends, and both ends resume the idle state and wait for a new call establishment triggered by the next off-hook.

1.1.2IP Voice Implementation over VRP

The router serves as voice gateway to provide voice functions, which makes data conversion from the circuit-switching network to the packet-switching network. During the conversion, you need to convert the phone numbers to the IP addresses that the

1-3

Page 199
Image 199
Huawei v200r001 user manual IP Voice Implementation over VRP, III. a typical telephone call processing by VoIP