Chapter 11: QoS Configuration Guide180 SmartSwitch Router User Reference ManualFor Layer-3 (IP and IPX) traffic, you can define “flows”, blueprints or templates of IP andIPX packet headers.• The IP fields are source IP address, destination IP address, UDP/TCP source port,UDP/TCP destination port, TOS (Type of Service), transport protocol (TCP or UDP),and a list of incoming interfaces• The IPX fields are source network, source node, destination network, destination node,source port, destination port, and a list of incoming interfacesThe flows specify the contents of these fields. If you do not enter a value for a field, awildcard value (all values acceptable) is assumed for the field.Precedence for Layer-3 FlowsA precedence from 1 - 7 is associated with each field in a flow. The SSR uses theprecedence value associated with the fields to break ties if packets match more than oneflow. The highest precedence is 1 and the lowest is 7. Here is the default precedence of thefields:• IP - destination port (1), destination address (2), source port (3), source IP address (4),TOS (5), interface (6), protocol (7)• IPX - destination network (1), source network (2), destination node (3), source node (4),destination port (5), source port (6), interface (7)Use the qos precedence ip and qos precedence ipx commands to change the defaultprecedence.SSR Queuing PoliciesYou can use one of two queuing policies on the SSR:• strict priority – assures the higher priorities of throughput but at the expense of lowerpriorities. For example, during heavy loads, low-priority traffic can be dropped topreserve throughput of control-priority traffic, and so on.• weighted fair queuing – distributes priority throughput among the four priorities(control, high, medium, and low) based on percentages.The SSR can use only one queuing policy at a time. The policy is used on the entire SSR.The default queuing policy is strict priority.
