Business Policy Switch 2000 Management Software

QoS parameters

Using DiffServ and QoS, you can designate a specific performance level for packets. This system allows you to prioritize network traffic. However, it requires some thought to configure the prioritizations.You can specify a number of policies, and each policy can match one or many flows--supporting complex classification scenarios.

This section contains a very simplified introduction to the many ways to prioritize packets using QoS. In simple terms, the methods of prioritizing packets depend on the DSCP and the 802.1 priority level and drop precedence.

The QoS class basically directs which group of packets receives the best network throughput, which group of packets receives the next best throughput, and so on. The level of service for each packet is determined by the configurable DSCP.

The available levels of QoS classes are currently named Premium, Platinum, Gold, Silver, Bronze, and Standard The level of service for each packet is determined by the configurable DSCP.

Filters and filter groups basically sort the packets by various configurable parameters. These parameters include VLAN ID, IP source and subnet address, IP protocol, 802.1q tagged/untagged packets, and many others.

The filter groups are organized into a precedence hierarchy. The filter group with the highest precedence is evaluated first. The filters and filter groups are associated with interface groups, in that packets from a specific port will have the same filters as all others in the particular interface group (role combination).

The queue sets associated with the ports are also part of interface groups. You configure which interface groups will have which level of service.

Meters, operating at ingress, keep the sorted packets within certain parameters. You configure a committed rate of traffic, allowing a certain size for a temporary burst, as In-Profile traffic. All other traffic is configured as Out-of Profile traffic.

Actions determine how the traffic is treated.

The overall total of all the interacting QoS factors on a group of packets is a policy. You configure policies, that monitor the characteristics of the traffic and perform a controlling action on the traffic when certain user-defined characteristics are matched.