Comtrol ES7528 - Manual (Page 104)

104 - CoS-Queue Mapping RocketLinx ES7528 User Guide: 2000509 Rev. C
Configuration Using the Web Interface
CoS-Queue Mapping
Use this page to change the CoS values into a Physical Queue mapping table. Since the switch fabric of the
ES7528 supports eight queues, Lowest, Low, Middle and High. You should therefore assign how to map CoS
value to the level of the 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 136 ), if you want to maintain these settings if the ES7528 is powered
off.
Use Weighted
Round Robin
scheme This scheme allows you to assign new weight ratio for each class. The 10 is the highest
ratio. The ratio of each class is:
Wx / W0 + W1 + W2 + W3 + W4 + W5 + W6 + W7 (Total volume of Queue 0-7)
Priority
Indicates the default port priority value for untagged or priority-tagged frames. When the
ES7528 receives the frames, the ES7528 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.
Default priority type is COS. The system provides default CoS-Queue table to which you
can refer for the next command.
Apply
Click Apply to apply the settings.
Note: You must Save the settings ( Page 136 ), if you want to maintain these settings if the
ES7528 is powered off.
QoS Setting Page (Continued)