Atec Agilent-J2300E - Manual (Page 9)

9
SSTED (Service Specific Transmission Error Detection) Sublayer
Fields decoded:
SSTED-PDU Payload
SSTED-PDU Trailer
- SSTED-UU (User-User indication)
- Reserved
- CI (Congestion Indication)
- LP (Loss Priority)
- Length
- CRC
Errors detected and displayed:
SSTED-PDU of length 8 or less has
been received
Incorrect length value of the SSTED-
PDU
Error in CRC
AAL – 3-4
Fields decoded:
Reassembly of segments for upper
layer decoding
Decode of CPCS layer (CS-PDU)
Check for segmentation errors in the
decode, such as
•Missing BOM or EOM
•Btag/Etag mismatch
•Check and flag of CRC-10 errors:
- MID
- BOM
- COM
- EOM
- Btag
- Etag
Errors detected and displayed:
ATM SDU not 48 bytes long
Invalid SAR sequence number
Invalid SAR length indicator
Invalid SAR CRCR protocol
simulation
CPCS common part indicator = 0
CPCS buffer allocation size is less
than the actual data size
CPCS begin tag = end tag
CPCS length is larger than the buffer
allocation size
SAR payload length is less than the
CPCS header length
SAR Payload length is less than
CPCS trailer length
AAL – 5
Fields decoded:
Re-assembly of segments for upper
layer
Decode of CPCS layer (CS-PDU)
Check and flag of CRC-32 errors
Display filtering on SDU type
Errors detected and displayed:
ATM SDU not 48 bytes long
Invalid SAR segment type
CPCS CPI=0
AAL-5 CRC-32
AAL-5 CRC statistics
Not an AAL-5 PDU
Note: The AAL-2 Service Specific Segmentation and Reassembly (SSSAR)
sublayer has, of course, been implemented below the SSTED sublayer but its
decode is not shown explicitly (the SSTED layer decode is sufficient)
ATM Testing (continued)