EtherWAN EX26262, Management Manual

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C
HAPTER
4
| Configuring the Switch
Quality of Service
Q
UALITY OF
S
ERVICE
All switches or routers that access the Internet rely on class information to
provide the same forwarding treatment to packets in the same class. Class
information can be assigned by end hosts, or switches or routers along the
path. Priority can then be assigned based on a general policy, or a detailed
examination of the packet. However, note that detailed examination of
packets should take place close to the network edge so that core switches
and routers are not overloaded.
Switches and routers along the path can use class information to prioritize
the resources allocated to different traffic classes. The manner in which an
individual device handles traffic is called per-hop behavior. All devices
along a path should be configured in a consistent manner to construct a
consistent end-to-end Quality of Service (QoS) solution.
This section describes how to specify which data packets have greater
precedence when traffic is buffered in the switch due to congestion. This
switch provides four priority queues for each port. Data packets in a port's
high-priority queue will be transmitted before those in the lower-priority
queues. You can set the default priority for each interface, the queuing
mode, and queue weights.
The switch also allows you to configure QoS classification criteria and
service policies. The switch’s resources can be prioritized to meet the
requirements of specific traffic types on a per hop basis. Each packet is
classified upon entry into the network based on Ethernet type, VLAN ID,
TCP/UDP port, DSCP, ToS, or its VLAN priority tag. Based on configured
network policies, different kinds of traffic can be marked for different kinds
of forwarding.
C
ONFIGURING
P
ORT
C
LASSIFICATION
Use the QoS Ingress Port Classification page to set the basic QoS
parameters for a port, including the default traffic class, DP level (IEEE
802.1p), user priority, drop eligible indicator, classification mode for tagged
frames, and DSCP-based QoS classification.
P
ATH
Advanced Configuration, QoS, Port Classification
P
ARAMETERS
These parameters are displayed:
QoS Ingress Port Classification
◆
Port – Port identifier.
◆
QoS class – Controls the default QoS class, i.e., the QoS class for
frames not classified in any other way. There is a one to one mapping
between QoS class, queue and priority. A QoS class of 0 (zero) has the
lowest priority. (Range: 0-7; Default: 0)