ZyXEL Communications GS2200-24 Differentiated Services, 29.1 Overview, 29.1.1What You Can Do, 29.1.2What You Need to Know

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Differentiated Services

29.1 Overview

This chapter shows you how to configure Differentiated Services (DiffServ) on the Switch.

Quality of Service (QoS) is used to prioritize source-to-destination traffic flows. All packets in the flow are given the same priority. You can use CoS (class of service) to give different priorities to different packet types.

DiffServ is a class of service (CoS) model that marks packets so that they receive specific per-hop treatment at DiffServ-compliant network devices along the route based on the application types and traffic flow. Packets are marked with DiffServ Code Points (DSCPs) indicating the level of service desired. This allows the intermediary DiffServ-compliant network devices to handle the packets differently depending on the code points without the need to negotiate paths or remember state information for every flow. In addition, applications do not have to request a particular service or give advanced notice of where the traffic is going.

29.1.1What You Can Do

•Use the DiffServ screen (Section 29.2 on page 263) to activate DiffServ to apply marking rules or IEEE 802.1p priority mapping on the Switch.

•Use the DSCP screen (Section 29.3.1 on page 264) to change the DSCP-IEEE 802.1p mapping.

29.1.2What You Need to Know

Read on for concepts on Differentiated Services that can help you configure the screens in this chapter.

DSCP and Per-Hop Behavior

DiffServ defines a new DS (Differentiated Services) field to replace the Type of Service (ToS) field in the IP header. The DS field contains a 6-bit DSCP field which

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GS2200-24 User’s Guide