Configuring Llq; Overview; Determining Bandwidth For The Queue - HP ProCurve Secure Router 7203 dl Advanced Management And Configuration Manual

Configuring LLQ

Overview

LLQ is a method for guaranteeing a set amount of bandwidth to certain traffic
and reducing this traffic's latency. You should use LLQ for voice and other real-
time applications that involve traffic that cannot tolerate excessive or variable
delay (jitter).
When a packet that matches the criteria for a low-latency queue arrives on an
interface, the router immediately places it in this queue. The low-latency queue
is always served first and is always given bandwidth up to the guaranteed level.
Low-latency traffic can also burst past its guaranteed level when bandwidth
is available. You can specify an upper limit for bursting low-latency traffic to
prevent it from entirely starving out other traffic.
Packets that do not match the criteria for the low-latency queue are served by
the queuing method enabled on the interface (FIFO or CBWFQ) with the
remaining bandwidth.
When you configure a low-latency queue on the ProCurve Secure Router, you
must configure:
the criteria for packets placed in the queue
the bandwidth guaranteed the queue

Determining Bandwidth for the Queue

LLQ allows you to manually determine the bandwidth a queue receives. Before
you configure a low-latency queue, you should plan for every queue that will
be implemented on the interface. You can then determine how much band-
width to assign each queue. If the interface also implements CBWFQ, you
should remember to take bandwidth allocated to classes into account.
This section of the guide gives you some general guidelines for determining
how much bandwidth you must allocate to:
VoIP traffic
video streams
You should, of course, refer to the documentation for your VoIP application
and follow any instructions given in that documentation first.
Setting Up Quality of Service
Configuring LLQ
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