Specifications

Sample Scenarios 59

Figure 25. IBM 2212 Voice Card Adapter

The IBM 2212 voice adapter has the following functions:

•E-CELP

•CS-ACELP

•VAD

• Echo Canceller

• Jitter Buffer

• Lost voice packet processing

• FAX support

4.0.4 BRS Super-Class

Bandwidth reservation allows you to reserve bandwidth at three levels:

• At the interface level, you can assign a percentage of the interface’s bandwidth

to circuit classes (c-classes). Each circuit class contains one or more circuits.

• At the circuit level, you can define traffic classes (t-classes) and allocate a

percentage of the circuit’s bandwidth.

• At the circuit level, you can define A traffic class created by the

create-super-class command is not associated with any bandwidth but always

takes priority over all other t-classes defined for the circuit.

When BRS receives a packet from frame relay, the configured c-classes and

t-classes are used to determine when that packet will be transmitted. BRS

queues the packet according to these criteria: c-class, circuit, t-class, and priority

within the t-class. The c-class to which the circuit has been assigned is put onto a

queue of c-classes and the queue of c-classes is sorted according to a fair

weighted queuing algorithm. Within a c-class, circuits that have packets to be

transmitted are serviced in a round-robin fashion. The t-classes within each

c-class are also sorted according to a fair weighted queuing algorithm. Within the

t-class, packets are further queued according to their priority (urgent, high,

normal, or low). A packet is removed from the queue and transmitted when it

meets all these criteria:

1. The next packet is in the next c-class.

2. The next packet in the next circuit is within the c-class.

3. One of the packets is in the next t-class for that c-class.

4. The next packet is in the next priority group for that t-class.

Voice card

LAN card

WAN

Frame Relay

Network

SNA

Analog

digital

2212

Voice

Analog/digital

conversion