Cos-queue mapping – Comtrol ES8510-XTE User Manual
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RocketLinx ES8510-XTE User Guide: 2000574 Rev. C
CoS-Queue Mapping - 95
Configuration Using the Web Interface
CoS-Queue Mapping
Use this page to change the CoS values into the Physical Queue mapping table. Since the switch fabric of
ES8510-XTE supports four queues, Lowest, Low, Middle, and High users should therefore assign how to map
the CoS value to the level of the physical queue.
You can assign the mapping table or follow the suggestion
of the IEEE 802.1p standard. The ES8510-XTE uses
IEEE 802.1p suggestion as default values. CoS Values 1
and 2 are mapped to physical Queue 0, the lowest queue.
CoS Values 0 and 3 are mapped to physical Queue 1, the
low/normal physical queue. CoS Values 4 and 5 are
mapped to physical Queue 2, the middle physical queue.
CoS Values 6 and 7 are mapped to physical Queue 3, the
high physical queue.
Class of service (CoS) is a 3 bit field within a layer two
Ethernet frame header defined by IEEE 802.1p when
using IEEE 802.1Q tagging. The field specifies a priority value of between 0 and 7 inclusive that can be used
by Quality of Service (QoS) disciplines to differentiate traffic.
While CoS operates only on Ethernet at the data link layer, other QoS mechanisms (such as DiffServ) operate
at the network layer and higher. Others operate on other physical layers. Although IEEE 802.1Q tagging
must be enabled to communicate priority information from switch to switch, some switches use CoS to
internally classify traffic for QoS purposes.
Differentiated Services (DiffServ) is a model where traffic is treated by intermediate systems with relative
priorities based on the type of services (ToS) field. Defined in RFC2474 and RFC2475, the DiffServ standard
supersedes the original specification for defining packet priority described in RFC791. DiffServ increases the
number of definable priority levels by reallocating bits of an IP packet for priority marking. The DiffServ
architecture defines the DiffServ field, which supersedes the ToS field in IPv4 to make per-hop behavior
(PHB) decisions about packet classification and traffic conditioning functions, such as; metering, marking,
shaping, and policing.
After configuration, press Apply to enable the settings.
Note: You must Save the settings (
), if you want to maintain these settings if the ES8510-XTE is
powered off.
Port Setting
CoS
The CoS column indicates that the default port priority value for untagged or priority-
tagged frames. When the ES8510-XTE receives the frames, the ES8510-XTE attaches the
value to the CoS field of the incoming VLAN-tagged packets. You can enable 0,1,2,3,4,5,6
or 7 to the port.
Trust Mode
Trust Mode indicates the Queue Mapping types that you can select.
•
COS Only (default): The port priority follows the CoS-Queue Mapping you have
assigned. The ES8510-XTE provides the default CoS-Queue table for which you can
refer to for the next command.
•
DSCP Only: Port priority only follows the DSCP-Queue Mapping you have assigned.
•
COS first: Port priority follows the CoS-Queue Mapping first, and then the DSCP-
Queue Mapping rule.
•
DSCP first: Port priority follows the DSCP-Queue Mapping first, and then the CoS-
Queue Mapping rule.
Apply
Click Apply to apply the settings.
Note: You must Save the settings (
), if you want to maintain these settings if the
ES8510-XTE is powered off.
QoS Setting Page (Continued)