Enabling cos marking, Example: cos marking, Dscp-based qos configuration – Brocade FastIron Ethernet Switch Traffic Management Guide User Manual
Page 33: Application notes for dscp-based qos, Enabling cos marking example: cos marking
The following example shows how to set the DSCP value to 4 of all IP packets on a specific port:
device(config)# interface ethernet1/1/1
device(config-if-e1000-1/1/1)# ip dscp-remark 4
Enabling CoS marking
To enable CoS marking globally, use the ip pcp-remark command in global configuration mode.
To enable CoS marking on a port, use the ip pcp-remark command in interface configuration mode.
Example: CoS marking
The following example shows how to set the PCP value to 3 for all VLAN tagged packets:
device(config)# ip pcp-remark 3
The following example shows how to set the PCP value to 4 of all IP packets on a specific port:
device(config)# interface ethernet1/1/1
device(config-if-e1000-1/1/1)# ip pcp-remark 4
DSCP-based QoS configuration
Brocade IronWare releases support basic DSCP-based QoS (also called Type of Service (ToS)-based
QoS) as described in this chapter. However, the FastIron family of switches does not support other
advanced DSCP-based QoS features.
Brocade IronWare releases also support marking of the DSCP value. The software can read Layer 3
Quality of Service (QoS) information in an IP packet and select a forwarding queue for the packet based
on the information. The software interprets the value in the six most significant bits of the IP packet
header 8-bit ToS field as a DSCP value, and maps that value to an internal forwarding priority.
NOTE
MAC filter and DSCP marking cannot be configured on the same port.
The internal forwarding priorities are mapped to one of the eight forwarding queues (qosp0 through
qosp7) on the Brocade device. During a forwarding cycle, the device gives more preference to the
higher-numbered queues, so that more packets are forwarded from these queues. For example, queue
qosp7 receives the highest preference, while queue qosp0, the best-effort queue, receives the lowest
preference.
Application notes for DSCP-based QoS
•
DSCP-based QoS is not automatically honored for routed and switched traffic. The default is
802.1p to CoS mapping. To honor DSCP-based QoS, you must either use an ACL or enable trust
DSCP. Refer to
Using ACLs to honor DSCP-based QoS
on page 32.
•
When DSCP marking is enabled, the device changes the contents of the inbound packet ToS field
to match the DSCP-based QoS value.
Enabling CoS marking
FastIron Ethernet Switch Traffic Management Guide
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