AAL 2 operation (cont.)

•  CID field (uniquely identifies user source) •  Length indicator (length of CPS packet) •  UUI field (service specific information) •  HEC (error check of CPS packet header only)

8

6

5

5

CPS packet header

CPS packet (CPS = Common Part Sub-layer)

H

Payload

H

ATM cell N

H

pad

Start field (1 byte)

ATM cell N+1