SMC Networks 7824M/FSW - annexe 1, Management Manual

Page: 579 / 748

RATE
-
LIMIT COS
27-3
rate-limit cos
This command defines the output rate limit for an interface based on
specified CoS priorities. Use the
no form to restore the default status of
disabled.
Syntax
rate-limit cos cos_value rate
no rate-limit cos
• cos_value – A number from 0 to 7, where 7 is the highest priority.
• rate – Maximum value in Mbps. (Range: Fast Ethernet - 1 to 100
Mbps, Gigabit Ethernet - 1 to 1000 Mbps)
Default Setting
Disabled
Command Mode
Interface Configuration (Ethernet, Port Channel)
Command Usage
• When priority-based rate limiting is implemented, the combined rate
of all traffic matching the specified priority-based rate limits cannot
exceed the overall output rate limit specified by the
rate-limit output
command (see page 27-2).
• If the rate exceeds the limit set for a specific priority, frames of that
type are dropped until the rate falls below the limit. If the rate exceeds
the overall limit set the
rate-limit output command, frames of any
priority type may be dropped until the rate falls back below the limit.
• This switch supports Class of Service by using eight priority queues.
Eight separate traffic classes are defined in IEEE 802.1p. The default
priority levels are assigned according to recommendations in the
IEEE 802.1p standard as shown below. To maintain line rate
throughput when setting rate limits for CoS priorities, only four
priority classes are supported by the switch, and are mapped from the
eight default priority classes as shown below.