Alcatel-Lucent 7210 SAS M Service Manual page 132

Circuit Emulation (Cpipe) Services
Packet Payload Size
The packet payload size defines the number of octets contained in the payload of a TDM
pseudowire packet when the packet is transmitted. Each DS0 (timeslot) in a DS1 or E1 frame
contributes 1 octet to the payload, and the total number of octets contributed per frame depends on
the number of timeslots in the channel group (for example, 10 timeslots contribute 10 octets per
frame).
Jitter Buffer
A circuit emulation service uses a jitter buffer to ensure that received packets are tolerant to packet
delay variation (PDV). The selection of jitter buffer size must take into account the size of the
TDM-encapsulated packets (payload size). A properly configured jitter buffer provides continuous
play-out, thereby avoiding discards due to overruns and under runs (packets arriving too early or
too late). The maximum receive jitter buffer size is configurable for each SAP configured for
circuit emulation. The range of values is from 1 to 250 ms in increments of 1 ms.
Configuration or Design Considerations
Determining the best configuration value for the jitter buffer may require some adjustments to
account for the requirements of your network, which can change PDV as nodes are added or
removed.
The buffer size must be set to at least three times the packetization delay and no greater than 32
times the packetization delay. Use a buffer size (in ms) that is equal to or greater than the peak-to-
Page 132 7210 SAS M Services Guide