Cabletron Systems SmartSwitch Router, Руководство пользователя

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Chapter 19: QoS Configuration Guide
284 SmartSwitch Router User Reference Manual
• Control
• High
• Medium
• Low
By assigning priorities to network traffic, you can ensure that critical traffic will reach its
destination even if the exit ports for the traffic are experiencing greater-than-maximum
utilization.
Layer-2 and Layer-3 & Layer-4 Flow Specification
For Layer-2 traffic, you can define a flow based on the MAC packet headers.
• The MAC fields are source MAC address, destination MAC address and VLAN IDs. A
list of incoming ports can also be specified
For Layer-3 (IP and IPX) traffic, you can define “flows”, blueprints or templates of IP and
IPX 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 interfaces.
The flows specify the contents of these fields. If you do not enter a value for a field, a
wildcard value (all values acceptable) is assumed for the field.
Precedence for Layer-3 Flows
A precedence from 1 - 7 is associated with each field in a flow. The SSR uses the
precedence value associated with the fields to break ties if packets match more than one
flow. The highest precedence is 1 and the lowest is 7. Here is the default precedence of the
fields:
• IP: destination port (1), destination IP 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 default
precedence.