Cos-Queue Mapping - Comtrol ES7506 User Manual

QoS Setting
Use a strict Packets with higher priority in the queue are always processed first, except that there is no packet with
priority scheme higher priority.
Port Setting
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
ES7506 provides the default COS-Queue table for which you can refer to for the next command.
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Trust Mode •
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Click Apply to apply the settings.
Apply
Note: You must Save the settings (Page 104), if you want to maintain these settings if the RocketLinx

CoS-Queue Mapping

Use this page to change the CoS values into the Physical Queue mapping table. Since the switch fabric of RocketLinx ES7506
only 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 RocketLinx ES7506 uses IEEE
802.1p suggestion as default values. You can find 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 (Page 104), if you want to maintain these settings if the RocketLinx ES7506 is powered off.
CoS-Queue Mapping
COS Only: The port priority only follows the CoS queue mapping that you have assigned. This is
the default.
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.
Port Based: The port priority follows the queue priority that you have assigned.
ES7506 is powered off.
Description
RocketLinx ES7506 User Guide: 2000529 Rev. E - 73
CoS-Queue Mapping