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Udp support, Packet delay variation – RAD Data comm IPmux-1 User Manual

Page 27

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IPmux-1/1E Installation and Operation Manual

Chapter 1 Introduction

Functional Description

1-19

802.1D Tag Protocol Type

81

00

user_priority

CFI =

0

VID

8

6

5

4

1

8

1

Priority

VLAN ID

Figure 1-17. VLAN Tag Format (802.1p&q)

UDP Support

Table 1-3. UDP Ports Definition

Field Length (Bits) Field Description

Value

Function

2 bytes

UDP Source Port

2–497d* Destination timeslots bundle

2 bytes

UDP Destination Port 2142d

Standard TDMoIP UDP port

* The MSB of this field can be either 1 or 0 for inband end-to-end proprietary signaling.

The UDP Source Port field is used for destination timeslots bundle indication.

For example, if the destination is:

Bundle 1 – 02, Bundle 2 – 03, Bundle 3 – 04, Bundle 4 – 05, etc.

For more information about VLAN tagging, refer to IEEE Std 802.1p&q.

Packet Delay Variation

Packets are transmitted at set intervals. Packet Delay Variation is the maximum

deviation from the nominal time the packets are expected to arrive at the far end
device. IPmux-1 has a buffer that compensates for the deviation from the expected

packet arrival time to prevent IPmux-1 buffers from emptying out or overflowing.
Packet Delay Variation is an important network parameter. Large PDV (exceeding

the jitter buffer configuration) will cause receive buffer underflows and errors at
the E1/T1 level (see Figure 1-18).
To compensate for large PDV, configure the PDVT (jitter) buffer to a higher value.

Note

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