Port Traffic Controls

Guaranteed Minimum Bandwidth (GMB)

Guaranteed Minimum Bandwidth (GMB)

Feature

Default

Menu

CLI

Web

bandwidth-min output

Per-Queue:

n/a

page 13-25

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2%-3%-30%-10%

 

 

 

 

10%-10%-15%-20%

 

 

 

show bandwidth output [ port-list]

n/a

n/a

page 13-28

n/a

 

 

 

 

 

Introduction

Guaranteed Minimum Bandwidth (GMB) provides a method for ensuring that each of a given port’s outbound traffic priority queues has a specified mini­ mum consideration for sending traffic out on the link to another device. This can prevent a condition where applications generating lower-priority traffic in the network are frequently or continually "starved" by high volumes of higher-priority traffic. You can configure GMB per-port.

Terminology

Oversubscribed Queue: The condition where there is insufficient bandwidth allocated to a particular outbound priority queue for a given port. If additional, unused bandwidth is not available, the port delays or drops the excess traffic.

GMB Operation

The switch services per-port outbound traffic in a descending order of priority; that is, from the highest priority to the lowest priority. By default, each port offers eight prioritized, outbound traffic queues. Tagged VLAN traffic is prior­ itized according to the 802.1p priority the traffic carries. Untagged VLAN traffic is assigned a priority of “0” (normal).

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