Cabletron Systems 9032578-05 manual QoS Rate Limiting, Port Rate Limiting

Appendix A: New Features Supported on Line Cards

on SSR C since SSR C does not have a -AA or T-series line card. SSR C would drop all SNA traffic since its module would not recognize SNA traffic.

QoS Rate Limiting

There are three types of rate limiting supported on the SSR:

•Per-flow rate limiting

•Aggregate rate limiting

•Port rate limiting

Per-Flow Rate Limiting

Per-flow rate limiting allows a network administrator to specify a bandwidth limit on an IP flow. If an IP flow exceeds the bandwidth limit, the excess traffic is either dropped or assigned to a lower priority. An IP flow can be specified using the IP header, Source IP, Destination IP, Source Port, Destination Port, or ToS Byte information. A rate-limiting profile is created to define the allowed bandwidth for this flow and then applied on the incoming IP interface.

Ports that are associated with the incoming IP interface must reside on -AA or T-series line cards. Ports that are associated with the outgoing interface do not require -AA or T-series line cards because no rate-limiting profile is required on the interface. In Diagram 4, a rate- limiting profile can be created to limit bandwidth for traffic sent from Client A to Client B even though Client B does not reside on a -AA or T-series line card. Note that in the current Per-flow rate limiting implementation, a rate-limiting profile can apply only on a layer 3/4 flow.

Aggregate Rate Limiting

Aggregate rate limiting allows a network administrator to specify a bandwidth limit on all flows that match one or more specified ACLs. You can use aggregate rate limiting to limit traffic to or from a particular subnet. A rate-limiting profile is created to define the allowed bandwidth for this traffic and then applied on the IP interface.

Ports that are associated with the IP interface must reside on a single T-series line card. You cannot apply an aggregate rate limiting policy to an interface that spans ports on more than one line card.

Port Rate Limiting

Port rate limiting allows a network administrator to specify a bandwidth limit on a particular port. You can limit either incoming or outgoing port traffic.

Ports that are rate limited must reside on T-series line cards.

SmartSwitch Router User Reference Manual 367