SMC Networks SMCFS2601, Руководство пользователя

Страница: 12 / 28

C
HAPTER
1
| Introduction
Overview
– 12 –
IEEE 802.1
P
Q
O
S
The SMCFS2601 switch supports 802.1p priority queuing Quality of Service,
which is an implementation of the IEEE 802.1p standard. With the 802.1p QoS
function, you can reserve bandwidth for important functions that require a lot of
bandwidth or have a high priority, such as VoIP (Voice-over Internet Protocol),
web browsing applications, or video conferencing. The switch has separate
hardware queues on each physical port to which packets from various
applications are mapped and priorities assigned.
The illustration below shows how 802.1p priority queuing is implemented on the
switch.
Figure 1: Mapping QoS on the Switch
There are two priority queues labeled TC0 and TC1. The untagged packets and
the eight IEEE 802.1p priority values (defined by the standard) are mapped to
the two priority queues on the switch. TC1 has the highest priority of the two
priority queues, while TC0 has the lowest priority.
The SMCFS2601 switch uses Weighted Robin Round (WRR) for scheduling. The
WRR queue-scheduling algorithm schedules all the queues in turn with every
queue assured a certain service time. The default weight values of TC0 and TC1,
are 1:16
Tag untag 0 1 2 3 4 5 6 7
Priority Queue TC0 TC1
Weight Value 1 2