Chapter 11 QoS
GS-1524/GS-1548 User’s Guide
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The following table describes the labels in this screen.
11.4.2 DSCP Based QoS
The Switch allows you to create a mapping table between Differentiated Services
Code Points (DSCPs) tags and IEEE 802.1p priority tags.
11.4.3 Differentiated Services Code Point (DSCP) Overview
Differentiated Services (DiffServ) is a class of service (CoS) model that marks
packets so that they receive specific per-hop treatment at DiffServ-compliant
network devices along the route based on the application types and traffic flow.
Packets are marked with DiffServ Code Points (DSCPs) indicating the level of
service desired. This allows the intermediary DiffServ-compliant network devices
to handle the packets differently depending on the code points without the need to
negotiate paths or remember state information for every flow. In addition,
applications do not have to request a particular service or give advanced notice of
where the traffic is going.
DiffServ defines a new DS (Differentiated Services) field to replace the Type of
Service (ToS) field in the IP header. The DS field contains a 2-bit unused field and
a 6-bit DSCP field which can define up to 64 service levels.
Table 18 Port Based QoS
LABEL DESCRIPTION
Mode Select Port Based QoS to specify priority rules based on the port of
incoming packets.
Change
Priority
Configure the following:
• Port - Select the number of the port for which you want to assign IEEE
802.1p priority to incoming frames.
• Priority - Select the IEEE 802.1p priority you want to assign to the
packets coming into the Switch on the port specified in the Port field.
Click Change to view your changed settings.
Note: The changes are not applied until you click Apply Change
Settings.
Port,
Priority
This is a summary table of your port to IEEE 802.1p priority mappings. The
Port column indicates the port number of the incoming packets and the
Priority column indicates what IEEE 802.1p priority gets assigned to those
packets.
Apply
Change
Settings
Click this when you have reviewed the changes you want to make and you
want to save them to the Switch’s memory.
