Configuring Classes Of Service - Siemens RUGGEDCOM ROX II User Manual

RUGGEDCOM ROX II
CLI User Guide
IMPORTANT!
Use the highest supported CoS with caution, as it is always used by the switch for handling network
management traffic, such as RSTP BPDUs.
If this CoS is used for regular network traffic, upon traffic bursts, it may result in the loss of some
network management frames, which in turn may result in the loss of connectivity over the network.
The process of controlling traffic based on CoS occurs over two phases:
• Inspection Phase
In the inspection phase, the CoS priority of a received frame is determined from:
▪ A specific CoS based upon the source and destination MAC address (as set in the Static MAC Address
Table)
▪ The priority field in 802.1Q tags
▪ The Differentiated Services Code Point (DSCP) component of the Type Of Service (TOS) field, if the frame is
IP
▪ The default CoS for the port
Each frame's CoS will be determined once the first examined parameter is found in the frame.
Received frames are first examined to determine if their destination or source MAC address is found in the
Static MAC Address Table. If they are, the CoS configured for the static MAC address is used. If neither
destination or source MAC address is in the Static MAC Address Table, the frame is then examined for 802.1Q
tags and the priority field is mapped to a CoS. If a tag is not present, the frame is examined to determine if it is
an IP frame. If the frame is IP and inspecting TOS is enabled, the CoS is determined from the DSCP field. If the
frame is not IP or inspecting TOS is disabled, the default CoS for the port is used.
After inspection, the frame is forwarded to the egress port for transmission.
• Forwarding Phase
Once the CoS of the frame is determined, the frame is forwarded to the egress port, where it is collected into
one of the priority queues according to the assigned CoS.
CoS weighting selects the degree of preferential treatment that is attached to different priority queues. The
ratio of the number of higher CoS to lower CoS frames transmitted can be configured. If desired, the user can
configure lower CoS frames to be transmitted only after all higher CoS frames have been serviced.
The following sections describe how to configure and manage classes of service:
• Section 5.34.1, "Configuring Classes of Service"
• Section 5.34.2, "Managing Priority-to-CoS Mapping"
• Section 5.34.3, "Managing DSCP-to-CoS Mapping"
Section 5.34.1

Configuring Classes of Service

To configure Classes of Service, do the following:
1. Make sure the CLI is in Configuration mode.
2. Configure the CoS weighting by typing:
switch classes-of-service cos-weighting weighting
Where:
Configuring Classes of Service
Chapter 5
Setup and Configuration
505