Digital Subscriber Line Access Multiplexer (DSLAM) Example Design
Digital Subscriber Line Access Multiplexer (DSLAM) Example Design
Digital Subscriber Line Access Multiplexer (DSLAM) Example Design
Create successful ePaper yourself
Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.
<strong>Digital</strong> <strong>Subscriber</strong> <strong>Line</strong> <strong>Access</strong> <strong>Multiplexer</strong> (<strong>DSLAM</strong>) <strong>Example</strong> <strong>Design</strong><br />
Figure 10 shows how Routed IP over ATM packets are encapsulated with LLC/SNAP and AAL5<br />
to be carried by ATM cells. These ATM cells are then prepended with the custom <strong>DSLAM</strong> header<br />
by the DSL Aggregator. The ATM cells with the prepended <strong>DSLAM</strong> headers are then input to the<br />
Receive Processor.<br />
Figure 10. Receive Processor Input - Routed IP over ATM with <strong>DSLAM</strong> Header<br />
Ethernet<br />
Data<br />
Ethernet Header<br />
IP Header<br />
TCP Header<br />
Payload<br />
Ethernet Trailer<br />
IP<br />
Data<br />
IP Header<br />
TCP Header<br />
Payload<br />
LLC/SNAP<br />
Encapsulation<br />
LLC OUI PID<br />
3 bytes 3 bytes 2 bytes IP Header TCP Header<br />
Payload<br />
AAL5<br />
CS<br />
CS-SDU Info Field<br />
Padding<br />
0-47 bytes<br />
UU<br />
1 byte<br />
CPI<br />
1 byte<br />
Length<br />
2 bytes<br />
CRC<br />
4 bytes<br />
SAR<br />
Sub-Layer<br />
ATM Cell<br />
Header<br />
Payload<br />
48 bytes<br />
ATM Cell<br />
Header<br />
Payload<br />
48 bytes<br />
ATM Cell<br />
Header<br />
Payload<br />
48 bytes<br />
<strong>DSLAM</strong><br />
(input to<br />
Processor A)<br />
<strong>DSLAM</strong> Header<br />
4 bytes<br />
ATM Cell<br />
53 bytes<br />
<strong>DSLAM</strong> Header<br />
4 bytes<br />
ATM Cell<br />
53 bytes<br />
Packet Type<br />
1 bit<br />
1=data<br />
Unused<br />
18 bits<br />
Physical Port Number<br />
11 bits<br />
(0-2047)<br />
Physical Port Type<br />
2 bits<br />
1=ATM<br />
A9553-01<br />
24 Application Note
Change language