3Com Network Jack NJ2000
Page 39 of 44
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QOS Configuration
QoS (Quality of Service) is a mechanism which is used to prioritize certain traffic as it is moves through the switch.
Traffic can be classified as High, Medium, Normal or Low priority. This switch features both strict priority-based
and weighted round-robin (WRR) forwarding, with guaranteed bandwidth allocation for the different QOS classes.
The queuing method can be selected using the
Queue Mode
drop-down list:
Strict priority
- Higher priority frames take precedence over lower priority frames during forwarding. In
case of congestion, the lowest priority traffic is dropped before higher priority frames. Head-of-queue
blocking maybe encountered by using this mode.
WRR
- In this mode, all priorities can be guaranteed a share of the bandwidth when the system is
overloaded. The bandwidth sharing percentage can be adjusted by specifying the four QOS class with
different ratio in
WRR Weight
, which appears after
WRR
is enabled in
Queue Mode
.
Note:
WRR
is selectable when
Jumbo Frame
is disabled in
Ports > Settings
.
You can select how traffic is prioritized by using one of the three QoS modes which is selected using the
QoS Mode
drop-down list:
QoS Disabled
- QoS is turned off and all packets have equal priority.
802.1p
- Packets are prioritized using the content of the VLAN-tag.
DSCP
- Packets are prioritized using the DSCP (Differentiated Services Code Point) value.
Note:
Only one QoS mode can be active at one time. It is not possible, for example, to prioritize traffic using the
DSCP
and
802.1p
