C
LASS

OF

S

ERVICE

C

ONFIGURATION

2-77

Class of Service Configuration
Class of Service (CoS) allows you to specify which data packets have
greater precedence when traffic is buffered in the switch due to
congestion. This switch supports CoS with fou r priority queues for each
port. Data packets in a port’s high-priority queue will be transmitted before
those in the lower-priority queues. You can set the default priority for each
interface, and configure the mapping of frame priority tags to the switch’s
priority queues.

Setting the Default Priority for Interfaces

You can specify the default port priority for each interface on the switch.
All untagged packets entering the switch are tagged with the specified
default port priority, and then sorted into the appropriate priority queue a t
the output port.
Command Usage
• This switch provides four priority queues for each port. It uses
Weighted Round Robin to prevent head-of-queue blockage.
• The default priority applies if the incoming frame is an untagged frame
received from a VLAN trunk or a static-access port. This priority does
not apply to IEEE 802.1Q VLAN tagged frames. If the incoming
frame is an IEEE 802.1Q VLAN tagged frame, the IEEE 802.1p User
Priority bits will be used.
Console(config)#interface ethernet 1/1 3-85
Console(config-if)#switchport acceptable-frame-types tagged 3-126
Console(config-if)#switchport ingress-filtering 3-127
Console(config-if)#switchport native vlan 3 3-128
Console(config-if)#switchport gvrp 3-132
Console(config-if)#garp timer join 10 3-134
Console(config-if)#garp timer leave 90 3-134
Console(config-if)#garp timer leaveall 2000 3-134
Console(config-if)#switchport mode hybrid 3-125
Console(config-if)#