Configuration Guide User guide

1740 FastIron Configuration Guide
53-1002494-02
QoS options for IP ACLs
QoS options for IP ACLs
Quality of Service (QoS) options enable you to perform QoS for packets that match the ACLs. Using
an ACL to perform QoS is an alternative to directly setting the internal forwarding priority based on
incoming port, VLAN membership, and so on. (This method is described in “QoS priorities-to-traffic
assignment” on page 1978.)
The following QoS ACL options are supported:
• dscp-cos-mapping – This option is similar to the dscp-matching command (described below).
This option maps the DSCP value in incoming packets to a hardware table that provides
mapping of each of the 0 – 63 DSCP values, and distributes them among eight traffic classes
(internal priorities) and eight 802.1p priorities.
By default, the Brocade device does the 802.1p to CoS mapping. If you want to change the
priority mapping to DSCP to CoS mapping, you must enter the following ACL statement.
permit ip any any dscp-cos-mapping
• dscp-marking – Marks the DSCP value in the outgoing packet with the value you specify.
• internal-priority-marking and 802.1p-priority-marking – Supported with the DSCP marking
option, these commands assign traffic that matches the ACL to a hardware forwarding queue
(internal-priority-marking), and re-mark the packets that match the ACL with the 802.1p priority
(802.1p-priority-marking).
• dscp-matching – Matches on the packet DSCP value. This option does not change the packet
forwarding priority through the device or mark the packet.
• 802.1p-priority-matching – Inspects the 802.1p bit in the ACL that can be used with adaptive
rate limiting. For details, refer to “Inspecting the 802.1p bit in the ACL for adaptive rate
limiting” on page 1781.
NOTE
These QoS options are only available if a specific ICMP type is specified for the <icmp-type>
parameter while configuring extended ACLS, and cannot be used with the any-icmp-type option. See
“Extended numbered ACL syntax” on page 1714 and “Extended named ACL syntax” on
page 1721for the syntax for configuring extended ACLs.
Configuration notes for QoS options on
FCX and ICX devices
• These devices do not support marking and prioritization simultaneously with the same rule
(and do not support DSCP CoS mapping at all). To achieve this, you need to create two
separate rules. In other words, you can mark a rule with DSCP or 802.1p information, or you
can prioritize a rule based on DSCP or 802.1p information. You can enable only one of the
following ACL options per rule:
• 802.1p-priority-marking
• dscp-marking
• internal-priority-marking
For example, any one of the following commands is supported.
FastIron(config)#access-list 101 permit ip any any dscp-marking 43