User Manual - Configuration Guide (Volume 3)

Chapter 1

Versatile Routing Platform

VoIP Configuration

packet switching can identify, therefore; the key factor of router configuration lies in the mapping of the phone numbers and the IP addresses.

The ports that support the voice function in the Quidway series routers include FXS (Foreign eXchange Station, i.e., the plain telephone service port), FXO (Foreign eXchange Office, two-wire loop trunk), the E&M trunk port and E1 voice port.

The device with FXS port type must be connected with the device with FXO port type (the ordinary telephone set is a standard FXO port). The ring current received by the FXS and FXO is AC current of 25Hz and 60 volts, while the signal received and sent in the E&M port is DC signal.

Table VC-1-1The match table between the plain switch and the router interconnection interface

Switch

 

Router

Capacity (channel)

 

 

 

 

Loop trunk line (FXS)

FXO

 

1

Subscriber line (FXO)

FXS

 

1

E&M trunk

E&M trunk

 

1

E1 trunk

E1 trunk

 

30

1.1.3 IP Voice Feature over VRP

The IP voice over the VRP abides by G.711 (A law), G.729, G.723.1, H.225.0, H.245, and standards such as RFC1889, 1890, etc., which can support the FXS, FXO, E&M port and E1 port.

The IP voice characteristics over the VRP include:

zSilence suppression

Automatically detect the time segments of silence during session and pause the generation of data flows during these time segments, so as to reduce the sent voice data quantity.

zComfort noise

Through generating appropriate background noise, the sharp voice between the speaking and pause that resulted from the silence suppression is avoided.

zJitter buffering

Jitter is caused by the variations of the data packet arrival rate in the network due to the time delay variation. In order to compensate this jitter, we have added a buffer to the voice devices at the receiving side to store data packets for enough time length. Thus, even the slowest packet can arrive in time for processing in sequence. In the mean time, the buffer can adjust the packet length of the voice port board, and send the voice data to the voice port board at a stable speed

zSupporting QoS

Since there is high requirement for the real-time voice service, precedence needs to be given to voice packet sending. You can take the measures such as setting Priority Queuing (PQ) and Custom Queuing (CQ) at the transmit end. For the configuration of PQ and CQ, please refer to the relevant sections of the “QoS Configuration “.

zSupporting IP Fax

The IP Fax system is established on the basis of the VoIP, which serves to establish the fax channel, transmit and receive the fax data. The IP Fax implementation includes modulation/demodulation, fax protocol processing, IP channel maintenance, etc.

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Huawei v200r001 user manual IP Voice Feature over VRP, Switch Router Capacity channel