Differentiated services or DiffServ is a computer networking architecture that specifies a mechanism for classifying and managing network traffic and providing quality of service (QoS) on modern IP networks.

This section provides the DSCP and precedence values used in QoS class maps and policy maps. Unless noted as a restriction, you can mark both incoming and outgoing packets. Table 6-1 lists the commonly used DSCP values described in RFC 2475. Table 6-2 lists the RFC 791 precedence values from least to most important.

Mar 16, 2009 · DSCP is a 6 bit field, the DSCP byte takes the place of the older TOS byte. IP precedence bits are only 3 the most meaningful (= leftmost) in the TOS byte definition. A class selector has set the first 3 bits in an attempt to be backward compatible with IP prec.

Sep 5, 2024 · Classes 1 to 4 are referred to as AF classes. This table illustrates the DSCP code that specifies the AF class with the probability. Bits DS5, DS4 and DS3 define the class; bits DS2 and DS1 specify the drop probability; bit DS0 is always zero.

This lesson explains IP Precedence, DSCP (Differentiated Services), codepoints, TOS byte, DS field, CS,AF and EF.

Jun 18, 2013 · CS and AF values have different dscp values. CS4 is 32 the nearest next dscp value is AF41 which is 34 followed by AF42 (36) and AF43 (38). CS is class selector and backwards compatible with ip precedence values.

Feb 1, 2024 · Differentiated Service Code Points (DSCP) is an aspect of QoS (Quality of Service) used to classify and manage network traffic. The DSCP field is 6 bits in length and can take on values from 0 to 63. DSCP is often described as “managed unfairness,” and with good reason.

Oct 11, 2023 · Differentiated Services (DiffServ) is defined as a class of service (COS) model that is used to describe and control the IP network traffic by class. The main aim of differentiated services is to give priority to the specific traffic that needs an uninterrupted flow of data.

Apr 26, 2017 · AF is just a easier way to represent DSCP values (0-63) with a main 0-7 class and then a drop selection priority. All AF values correspond directly to DSCP 0-63 values as I show below. Only 6 out of 8 bits are typically used in the Type of Service (QoS) byte in an IP header.

Mar 22, 2006 · RFC 2597 defines a group of DSCP settings called “Assured Forwarding” Per Hop Behavior (PHB) to be recognized by RFC compliant DSCP routers and switches called DS nodes. The Assured Forwarding PHB class is presented as AF(xy), where x=traffic class, and y=drop precedence. 4 traffic classes, and 3 drop precedences are defined.