Chapter4 Policy-enabled networks 289
Using the Business Policy Switch 2000 Version 1.2
•Interface groups
The policies, by connecting these user-defined configurations, control the traffic
on the switch.
Ports are assigned to interface groups that are linked to policies. The policies
determine the traffic treatment of the flows.
Packet flow using QoS
Using DiffServ and QoS, you can designate a specific performance level for
packets. This system allows you to prioriti ze 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 intro duction to the many ways to prioritize
packets using QoS. In simple terms, the methods of prioritizing packe ts 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 determ ined 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, and many others.
The filter groups are associated with policies, and policies are organized into a
hierarchy. The policy with the highest preceden ce is evalua ted first. The filters an d
filter groups are associated with interface groups, in that packets from a specific
port will have the same filters as all others in th e particular interface group (role
combination).