Specifications

Chapter 1 Product Overview
Application Notes
1-14
Catalyst 4224 Access Gateway Switch Software Configuration Guide
OL-2031-02
InterVLAN Routing
The forwarding performance for interVLAN routing on the Catalyst 4224 is
35 Kpps for 64-byte packets. Fast Switching is the default switching path. The
Catalyst 4224 supports Cisco Express Forwarding (CEF).
Quality of Service
The Catalyst 4224 can function as a Layer 2 switch connected to a Layer 3 router.
When a packet enters the Layer 2 engine directly from a switch port, it is placed
into one of four queues in the dynamic, 32-Mbyte shared memory buffer. The
queue assignment is based on the dot1p value in the packet. Any voice bearer
packets that come in from the IP phones on the voice VLAN are automatically
placed in the highest priority (Queue 3) based on the 802.1p value generated by
the IP phone. The queues are then serviced on a WRR basis. The control traffic,
which uses a CoS/ToS of 3, is placed in Queue 2.
Layer 2 QoS
Table 1-3 summarizes the queues, CoS values, and weights for Layer 2 QoS on
the Catalyst 4224.
The weights specify the number of packets that are serviced in the queue before
moving on to the next queue. Voice Real-Time Transport Protocol (RTP) bearer
traffic marked with a CoS /ToS of 5 and Voice Control plane traffic marked with
Table 1-3 Queues, CoS values, and Weights for Layer 2 QoS
Queue Number CoS Value Weight
3 5,6,7 255
23,464
1216
00,11