Canonical URL: ; File formats: Plain Text PDF Discuss this RFC: Send questions or comments to [email protected] Differentiated services or DiffServ is a computer networking architecture that specifies a simple In December , the IETF published RFC – Definition of the Differentiated services field (DS field) in the IPv4 and IPv6 headers, which. The type of service (ToS) field is the second byte of the IPv4 header. It has had various In RFC the definition of this entire field was changed. It is now.

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The entire ToS field would then gfcassuming that the unused 5 bits are zero. Network traffic entering a DiffServ domain is subjected to classification and conditioning. RFC introduced an additional “lowcost” field. Each router on the network is then configured to differentiate traffic based on its class. Because the last three bits went through many definitions prior to RFC see belowdocumentation and implementations may be confusing and contradictory.

It is up to all the service providers and their routers in the path to ensure that their policies will take care of the packets in an appropriate fashion. The above table, with individual values written out for values of the entire TOS field not to be confused with the little-used 5-bit part:.

In practice, however, most networks use the following commonly rtc per-hop behaviors:. The standard traffic classes discussed below serve to simplify interoperability between different networks and different vendors’ equipment.


The four available ToS bits now becomes:. Since no classification and policing is required in the core router, functionality there can then be kept simple. PHB treatment is achieved by core routers using a combination of scheduling policy and queue management policy.

RFC – Differentiated Services and Tunnels

This means that in the core of the Internet, routers are unhindered by the complexities of collecting payment or enforcing agreements. From a commercial viewpoint this means that it is impossible to sell different classes of end-to-end connectivity to end users, as one provider’s Gold packet may be another’s Bronze.

EF traffic is often given strict priority queuing above all other traffic classes. From Wikipedia, the free encyclopedia. In theory, a network could have up to 64 different traffic classes using the 64 available DSCP values. This is complicated further if a packet crosses two or more DiffServ domains before reaching its destination.

The per-hop behavior is determined by the DS field in eitf IP header. In RFC the definition of this entire field was changed.

Type of service

This page was last edited on 24 Decemberat By using this site, you agree to the Terms rdc Use 24774 Privacy Policy. Retrieved 10 October Traffic classifiers may honor any DiffServ markings in received packets or may elect to ignore or override those markings. Views Read Edit View history. Retrieved from ” https: Essentially, any traffic that does not meet the requirements of any of the other defined classes uses DF. From Wikipedia, the free encyclopedia.


Each IP precedence value can be mapped into a DiffServ class. Because an overload of EF traffic will cause queuing delays and affect the jitter and delay tolerances within the class, EF traffic is often strictly controlled through admission control, policing and other mechanisms.

While DiffServ does recommend a standardized set of traffic classes, [3] the DiffServ architecture does not incorporate predetermined judgments of what types of traffic should be given priority treatment. The type of service ToS field is the second byte of the IPv4 header.

Information on RFC ยป RFC Editor

Retrieved from ” https: DiffServ simply provides a framework to allow classification and differentiated treatment. Webarchive template wayback links Use American English from April All Wikipedia articles written in American Iet All articles with unsourced statements Articles with unsourced statements from June The details of how individual routers deal with the DS field is configuration specific, therefore it is difficult to predict end-to-end behaviour.

Modern data networks carry many different types of services, including voice, video, streaming music, web pages and email. It defined a mechanism for assigning a precedence to each IP packet, as well as a mechanism to request specific treatment such as high throughput, high reliability or low latency, etc.