Atec Agilent-J2300E - Manual (Page 8)

8
ATM Testing
(continued ) ATM Adaptation Layer (AAL)
The Agilent Advisor provides decodes for AAL-1 through AAL-5. Decodes are
also included for AAL-2 Common Part Sublayer (AAL-2 CPS to ITU-T I.363.2)
and AAL-2 Service Specific Segmentation and Reassembly sublayer (AAL-2
SSSAR to ITU-T I.366.1). Note: AAL-1 & AAL-2 decodes are not currently
supported at 622 Mb/s. The Decode screen in figure 1 depicts an AAL-2
sublayer.
AAL – 1
Fields decoded:
CSI
Sequence number
CRC
Parity
Payload
Errors detected and displayed:
ATM SDU not 48 bytes long
Invalid sequence number
Invalid parity
Invalid CRC-3
AAL – 2
CPS (Common Part Sublayer)
Fields decoded:
CPS-PDU start field (STF)
- OSF (Offset field)
- SN (Sequence number)
- P (Parity)
CPS-Packet (one or more)
CPS- Packet Header (CPS-PH)
- CID Channel identifier
- LI Length Indicator
- UUI (User to user indication)
- HEC
CPS-Packet Payload (CPS-PP)
CPS-INFO
Padding
Errors detected and displayed:
STF Parity error
STF Sequence number error
Number of octets expected in the
CPS packet does not match with
the STF field
Error in the OSF value (>=48)
Error in HEC
Length of received packet is incorrect.
Errors in reassembly.
Invalid value in UUI
Figure 1: CPS (Common Par t Sublayer).