
Configuring ATM Services
1-6
AAL 5
In AAL 5, only a trailer attaches to the data from the higher layer protocols to
create a CS PDU. AAL 5 divides the PDU into a 48-octet SAR PDU; however, it
does not add an SAR header and trailer. This 48-octet SAR PDU becomes the
payload of the ATM cell (Figure 1-5).
Figure 1-5. ATM Adaptation Layer 5
Service Data Unit (SDU)
SAR PDU
ATM Cell
SDU
SAR PDU
SAR PDU
ATM Cell
ATM Cell
AAL 5
Convergence
Sublayer
AAL 5
SAR
Layer
ATM
Layer
AAL
Layer
Service
Class
Trailer
Note: AAL 5 does not attach an SAR header or trailer to the PDU.
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