Rtp header, Measuring voip parameters – Agilent Technologies N2620A User Manual

Page 137

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Generating Voice Traffic with the FrameScope Pro

4

N2620A User’s Guide

119

RTP Header

Each call is represented by an RTP stream with the following
properties.

Header data.

Version: 2.

The Payload Type (PT) is determined by the codec. It is
the same for all packets.

The sequence number for the packets in a call starts with
a random number, then increments by one for each
packet.

The timestamp for the packets in a call starts at the
current time of the FrameScope Pro, then increments
according to the codec type.

The SSRC identifier is the same for all the packets for a
call, but different for each RTP stream.

All other header fields are set to zero.

The Payload Data is random.

Measuring VoIP Parameters

Use the Agilent J6844A Telephone Network Analyzer (TNA) to
measure MOS and other VoIP related parameters of the traffic
generated by the FrameScope Pro.

The TNA does not calculate the MOS silence value which is 0.

Call

number

Packet

number

SSRC ID

Sequence

Timestamp

(based on codec type)

1

1

SSRC1 2394 (random number)

0

2

SSRC1

2395

160

3

SSRC1

2396

320

...

...

...

...

2

1

SSRC2 3957 (random number)

0

2

SSRC2

3958

160

...

...

...

...

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