| AAL
1 (cont.) |
|
|
| When
transmitting low & variable bit rate signals, the |
|
| problem with AAL 1 is
even worse: |
|
| Packing delay may be even
larger ... |
| h |
| payload |
| h |
| payload |
| h |
| payload |
| (8 kb/s speech encoding:
47/1000 = 47 ms) |
| ... or transmission
efficiency even lower |
| h |
| payload |
| h |
| payload |
| h |
| payload |
|
|
| => use AAL 2
which offers multiplexing of different |
|
| signals into the same ATM
cell |
|