LevelOne GTL-2691 User Manual

Page 1177

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C

HAPTER

41

| Quality of Service Commands

– 1177 –

committed-rate - Committed information rate (CIR) in kilobits per

second. (Range: 1-1000000 kbps or maximum port speed,

whichever is lower)
committed-burst - Committed burst size (BC) in bytes.

(Range: 64-524288)
excess-burst - Excess burst size (BE) in bytes.

(Range: 64-524288)
exceed-action - Action to take when rate exceeds the CIR and BC

but is within the BE. (There are enough tokens in bucket BE to

service the packet, the packet is set yellow.)
violate-action - Action to take when rate exceeds the BE. (There
are not enough tokens in bucket BE to service the packet, the

packet is set red.)
drop - Drops packet as required by exceed-action or violate-action.
new-dscp - Differentiated Service Code Point (DSCP) value.

(Range: 0-63)

D

EFAULT

S

ETTING

None

C

OMMAND

M

ODE

Policy Map Class Configuration

C

OMMAND

U

SAGE

You can configure up to 16 policers (i.e., class maps) for ingress ports.

The committed-rate cannot exceed the configured interface speed, and

the committed-burst and excess-burst cannot exceed 16 Mbytes.

The srTCM as defined in RFC 2697 meters a traffic stream and

processes its packets according to three traffic parameters –

Committed Information Rate (CIR), Committed Burst Size (BC), and

Excess Burst Size (BE).

The PHB label is composed of five bits, three bits for per-hop behavior,

and two bits for the color scheme used to control queue congestion. A

packet is marked green if it doesn't exceed the CIR and BC, yellow if it

does exceed the CIR and BC, but not the BE, and red otherwise.

The meter operates in one of two modes. In the color-blind mode, the

meter assumes that the packet stream is uncolored. In color-aware

mode the meter assumes that some preceding entity has pre-colored

the incoming packet stream so that each packet is either green, yellow,

or red. The marker (re)colors an IP packet according to the results of

the meter. The color is coded in the DS field [RFC 2474] of the packet.

The behavior of the meter is specified in terms of its mode and two

token buckets, C and E, which both share the common rate CIR. The

maximum size of the token bucket C is BC and the maximum size of the

token bucket E is BE.

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