Netgear XCM8810 Chassis User Manual - Page 367

NETGEAR 8800 User Manual Single-rate rate-limiters pass traffic that is in-profile or marked green. Out-of-profile traffic (marked red) is subject to whatever action is configured for out-of-profile traffic. Out of profile traffic can be forwarded if bandwidth is available, dropped, or marked for a possible drop later in the communication path. For example, you can configure a peak rate (PR) for single-rate rate-limiting. All traffic that arrives at or below the PR is considered in-profile and marked green. All traffic that arrives above the PR is considered out-of-profile and marked red. When the traffic exceeds the capacity of the rate-limiting component, all traffic that is marked red is dropped. Another type of single-rate QoS is used on NETGEAR 8800 switches. A committed information rate (CIR) establishes a reserved traffic rate, and a peak burst size (PBS) establishes a maximum size for a traffic stream. If a traffic stream is at or below the CIR and the PBS, it is considered to be within profile and marked green. If a traffic stream exceeds either the CIR or the PBS, it is considered out-of-profile and marked red. On these switches, you can configure the single-rate rate-limiting components to drop traffic marked red or set a drop precedence for that traffic. You can also specify a DSCP value to mark the out-of-profile traffic. Dual-rate QoS Dual-rate QoS defines two rates for traffic that is subject to QoS. The lower of the two rates is the CIR, which establishes a reserved traffic rate. The higher of the two rates is the PR, which establishes an upper limit for traffic. Dual-rate QoS is well suited to bursty traffic patterns which are common with typical data traffic. Dual-rate QoS is widely used in legacy Frame Relay and ATM leased lines. Note: You must configure the peak rate higher than the committed rate. A three-color system is used with dual-rate QoS. As with single-rate QoS, traffic at or below the CIR is considered in-profile, marked green, and forwarded. The traffic that is above the CIR and below the PIR is out-of-profile and marked yellow. Traffic above the PIR is also out-of-profile and marked red. When incoming traffic is already marked yellow and is out of profile, it is marked red. Different switch platforms take different actions on the traffic marked yellow or red. Rate Specification Options The XCM8800 software allows you to specify the CIR and PR in gigabits per second (Gbps), megabits per second (Mbps), or kilobits per second (Kbps). Most commands also allow you to specify the CIR and PR as a percentage of the maximum port bandwidth using the minbw (CIR) and maxbw (PR) options. The default value on all minimum bandwidth parameters is 0%, and the default value on all maximum bandwidth parameters is 100%. QoS can be applied at different locations in the traffic path using the following rate-limiting and rate-shaping components: • Ingress meters Chapter 15. QoS | 367