DiffServ

DiffServ
Name	DiffServ
Purpose	Quality of Service
Developer	Internet Engineering Task Force
Introduced	1998

DiffServ is a Quality of Service (QoS) architecture that provides a scalable and flexible way to manage network traffic, developed by the Internet Engineering Task Force (IETF) and introduced in 1998, with key contributions from Cisco Systems, Juniper Networks, and IBM. The DiffServ model is based on the concept of traffic classification, where packets are marked with a specific Differentiated Services Code Point (DSCP) value, which determines the level of service they receive, as defined by the IETF Request for Comments (RFC) 2474 and RFC 2475. This approach allows for efficient and effective management of network resources, as demonstrated by AT&T, Verizon Communications, and BT Group. The DiffServ architecture has been widely adopted by Internet Service Providers (ISPs) such as Comcast, Time Warner Cable, and Orange S.A., and is also used in various Network Operating Systems (NOS) including Cisco IOS, Junos, and Windows Server.

Introduction to DiffServ

The DiffServ architecture was designed to address the limitations of the Integrated Services (IntServ) model, which was developed by the IETF in the mid-1990s, with input from MIT, Stanford University, and University of California, Berkeley. The IntServ model used a per-flow approach, where each flow was treated individually, which led to scalability issues, as experienced by America Online and EarthLink. In contrast, the DiffServ model uses a per-class approach, where packets are classified into a limited number of classes, each with its own set of QoS parameters, as defined by the IETF DiffServ Working Group. This approach allows for more efficient use of network resources and better scalability, as demonstrated by Google, Amazon Web Services, and Microsoft Azure. The DiffServ model has been widely adopted by Telecom Operators such as Deutsche Telekom, Telefónica, and Vodafone Group, and is also used in various Network Devices including Routers, Switches, and Firewalls from HP, Dell, and Fortinet.

Architecture and Components

The DiffServ architecture consists of several key components, including Classifiers, Metering, Marking, Shaping, and Policing, as defined by the IETF DiffServ Working Group. Classifiers are used to identify and classify packets into different classes, based on their DSCP value, as implemented by Cisco Systems and Juniper Networks. Metering is used to measure the rate at which packets are being sent, as demonstrated by IBM and Oracle Corporation. Marking is used to set the DSCP value of packets, as defined by the IETF Request for Comments (RFC) 2474 and RFC 2475. Shaping is used to control the rate at which packets are sent, as implemented by AT&T and Verizon Communications. Policing is used to enforce the QoS parameters of each class, as demonstrated by BT Group and Orange S.A.. The DiffServ architecture also includes several Per-Hop Behaviors (PHBs), which define the QoS parameters for each class, as defined by the IETF DiffServ Working Group and implemented by Google, Amazon Web Services, and Microsoft Azure.

Classifiers and Per-Hop Behaviors

Classifiers are a critical component of the DiffServ architecture, as they are used to identify and classify packets into different classes, based on their DSCP value, as implemented by Cisco Systems and Juniper Networks. There are several types of classifiers, including BA (Behavior Aggregate) classifiers, MF (Multi-Field) classifiers, and FF (Filtering) classifiers, as defined by the IETF DiffServ Working Group. PHBs are used to define the QoS parameters for each class, and there are several standardized PHBs, including EF (Expedited Forwarding), AF (Assured Forwarding), and BE (Best Effort), as defined by the IETF Request for Comments (RFC) 2597, RFC 2598, and RFC 3246. The DiffServ architecture also includes several Traffic Conditioning mechanisms, which are used to enforce the QoS parameters of each class, as demonstrated by AT&T, Verizon Communications, and BT Group.

Traffic Conditioning and Policing

Traffic conditioning is a critical component of the DiffServ architecture, as it is used to enforce the QoS parameters of each class, as demonstrated by IBM and Oracle Corporation. There are several traffic conditioning mechanisms, including Shaping, Policing, and Marking, as defined by the IETF DiffServ Working Group. Shaping is used to control the rate at which packets are sent, as implemented by Cisco Systems and Juniper Networks. Policing is used to enforce the QoS parameters of each class, as demonstrated by Google, Amazon Web Services, and Microsoft Azure. Marking is used to set the DSCP value of packets, as defined by the IETF Request for Comments (RFC) 2474 and RFC 2475. The DiffServ architecture also includes several Queue Management mechanisms, which are used to manage the queues of packets in network devices, as implemented by HP, Dell, and Fortinet.

Configuration and Implementation

The configuration and implementation of DiffServ is a complex task, as it requires careful planning and design, as demonstrated by AT&T, Verizon Communications, and BT Group. The first step is to define the QoS parameters for each class, based on the requirements of the network, as defined by the IETF DiffServ Working Group. The next step is to configure the classifiers, metering, marking, shaping, and policing mechanisms, as implemented by Cisco Systems and Juniper Networks. The DiffServ architecture can be implemented using a variety of Network Devices, including Routers, Switches, and Firewalls, as demonstrated by Google, Amazon Web Services, and Microsoft Azure. The configuration and implementation of DiffServ can be done using a variety of Network Management tools, including SNMP (Simple Network Management Protocol) and NetFlow, as implemented by IBM and Oracle Corporation.

Applications and Use Cases

The DiffServ architecture has a wide range of applications and use cases, including VoIP (Voice over Internet Protocol), Video Streaming, and Online Gaming, as demonstrated by Skype, Netflix, and Electronic Arts. The DiffServ architecture can be used to provide QoS guarantees for critical applications, such as Emergency Services and Financial Transactions, as implemented by AT&T, Verizon Communications, and BT Group. The DiffServ architecture can also be used to provide QoS guarantees for Cloud Computing and Big Data applications, as demonstrated by Google, Amazon Web Services, and Microsoft Azure. The DiffServ architecture has been widely adopted by Telecom Operators and Internet Service Providers (ISPs) around the world, including Deutsche Telekom, Telefónica, and Vodafone Group, and is also used in various Network Devices including Routers, Switches, and Firewalls from HP, Dell, and Fortinet.

Category:Network protocols