Avaya X330WAN manual QoS and VoIP Treatment, QoS Implementation for PPP Encapsulation

QoS and VoIP Treatment

QoS and VoIP Treatment

X330WAN enforces QoS on the ingress and egress flows. QoS implementation depends on the X330WAN encapsulation method, described below.

QoS Implementation for PPP Encapsulation

Incoming packets to X330WAN are classified and queued in one of the two available Rx queues. Separation is performed on packets to be transmitted on a per-interface basis, with four queues servicing each serial interface. The general X330WAN QoS concept is shown in Figure 4.8.

Figure 4.8 QoS Queues

As illustrated in Figure 4.8, incoming packets are classified into two queues where Weighted Random Early Detection (WRED) is implemented on the packets. WRED serves as a flow control mechanism, enabling the sending TCP peer to adjust its transmission rate based on the X330WAN average ingress queue congestion.

The usual queuing mechanism begins dropping all packets without previous warning when the queue becomes completely congested. As opposed to this the WRED mechanism ensures a gradual increase in the probability of a packet being dropped based on the queue congestion at any given moment. This gradual increase

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