Cisco 7609-S Software Configuration Guide - Page 666

Configuring PFC QoS Chapter 41 Configuring PFC QoS - The minimum token bucket size is 1 kilobyte, entered as 1000 (the maximum_burst_bytes parameter must be set larger than the normal_burst_bytes parameter). - The maximum token bucket size is 512 megabytes, entered as 512000000. - To sustain a specific rate, set the token bucket size to be at least the rate value divided by 4000 because tokens are removed from the bucket every 1/4000th of a second (0.25 ms). - Because the token bucket must be large enough to hold at least one frame, set the parameter larger than the maximum size of the traffic being policed. - For TCP traffic, configure the token bucket size as a multiple of the TCP window size, with a minimum value at least twice as large as the maximum size of the traffic being policed. • The valid range of values for the pir bits_per_second parameter is as follows: - Minimum-32 kilobits per second, entered as 32000 (the value cannot be smaller than the CIR bits_per_second parameters) - Maximum with Release 12.2(18)SXE and later releases: 10 gigabits per second, entered as 10000000000 - Maximum with releases earlier than Release 12.2(18)SXE: 4 gigabits per second, entered as 4000000000 • (Optional) You can specify a conform action for matched in-profile traffic as follows: - The default conform action is transmit, which sets the policy map class trust state to trust DSCP unless the policy map class contains a trust command. - To set PFC QoS labels in untrusted traffic, enter the set-dscp-transmit keyword to mark matched untrusted traffic with a new DSCP value or enter the set-prec-transmit keyword to mark matched untrusted traffic with a new IP precedence value. The set-dscp-transmit and set-prec-transmit keywords are only supported for IP traffic. PFC QoS sets egress ToS and CoS from the configured value. - Enter the drop keyword to drop all matched traffic. Note When you configure drop as the conform action, PFC QoS configures drop as the exceed action and the violate action. • (Optional) For traffic that exceeds the CIR, you can specify an exceed action as follows: - The default exceed action is drop, except with a maximum_burst_bytes parameter (drop is not supported with a maximum_burst_bytes parameter). Note When the exceed action is drop, PFC QoS ignores any configured violate action. - Enter the policed-dscp-transmit keyword to cause all matched out-of-profile traffic to be marked down as specified in the markdown map. Note When you create a policer that does not use the pir keyword and the maximum_burst_bytes parameter is equal to the normal_burst_bytes parameter (which is the case if you do not enter the maximum_burst_bytes parameter), the exceed-action policed-dscp-transmit keywords cause PFC QoS to mark traffic down as defined by the policed-dscp max-burst markdown map. 41-64 Cisco 7600 Series Router Cisco IOS Software Configuration Guide, Release 12.2SX OL-4266-08