13-1
Chapter 13: Class of Service
Class of Service (CoS) allows you to specify which data packets have greater
precedence when traffic is buffered in the switch due to congestion. This switch
supports CoS with eight 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, and configure the mapping of frame
priority tags to the switch’s priority queues.
Layer 2 Queue Settings
Setting the Default Priority for Interfaces
You can specify the default port priority for each interface on the switch. All untagged
packets entering the switch are tagged with the specified default port priority, and
then sorted into the appropriate priority queue at the output port.
Command Usage
• This switch provides eight priority queues for each port. It uses Weighted Round
Robin to prevent head-of-queue blockage.
• The default priority applies for an untagged frame received on a port set to accept
all frame types (i.e, receives both untagged and tagged frames). This priority does
not apply to IEEE 802.1Q VLAN tagged frames. If the incoming frame is an IEEE
802.1Q VLAN tagged frame, the IEEE 802.1p User Priority bits will be used.
• If the output port is an untagged member of the associated VLAN, these frames are
stripped of all VLAN tags prior to transmission.
Command Attributes
•
Default Priority
15
– The priority that is assigned to untagged frames received on
the specified interface. (Range: 0 - 7, Default: 0)
•
Number of Egress Traffic Classes
– The number of queue buffers provided for
each port.
15. CLI displays this information as “Priority for untagged traffic.”
Summary of Contents for 8926EM
Page 6: ...ii ...
Page 34: ...Getting Started ...
Page 44: ...Introduction 1 10 1 ...
Page 62: ...Initial Configuration 2 18 2 ...
Page 64: ...Switch Management ...
Page 76: ...Configuring the Switch 3 12 3 ...
Page 118: ...Basic Management Tasks 4 42 4 ...
Page 164: ...User Authentication 6 28 6 ...
Page 176: ...Access Control Lists 7 12 7 ...
Page 284: ...Quality of Service 14 8 14 ...
Page 294: ...Multicast Filtering 15 10 15 ...
Page 300: ...Domain Name Service 16 6 16 ...
Page 310: ...Dynamic Host Configuration Protocol 17 10 17 ...
Page 320: ...Configuring Router Redundancy 18 10 18 ...
Page 344: ...IP Routing 19 24 19 ...
Page 356: ...Unicast Routing 20 12 20 Web Click Routing Protocol RIP Statistics Figure 20 5 RIP Statistics ...
Page 386: ...Unicast Routing 20 42 20 ...
Page 388: ...Command Line Interface ...
Page 400: ...Overview of the Command Line Interface 21 12 21 ...
Page 466: ...SNMP Commands 24 16 24 ...
Page 520: ...Access Control List Commands 26 18 26 ...
Page 546: ...Rate Limit Commands 30 2 30 ...
Page 612: ...VLAN Commands 34 24 34 ...
Page 626: ...Class of Service Commands 35 14 35 ...
Page 670: ...DHCP Commands 39 16 39 ...
Page 716: ...IP Interface Commands 41 36 41 ...
Page 768: ...IP Routing Commands 42 52 42 ...
Page 770: ...Appendices ...
Page 791: ......