Introduction to Differentiated Services (DiffServ) and HP-UX IPQoS

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Introduction to Differentiated Services (DiffServ) and HP-UX

IPQoS

What is Quality of Service (QoS)?......................................................................................................... 2

Differentiated Services (DiffServ)............................................................................................................ 2

Overview........................................................................................................................................ 2

Example – XYZ Corporation .............................................................................................................. 2

Components of DiffServ........................................................................................................................ 3

Traffic Classification and Conditioning ............................................................................................... 3

Classification ............................................................................................................................... 3

Conditioning................................................................................................................................ 4

HP-UX IPQoS....................................................................................................................................... 6

Configuration .................................................................................................................................. 6

Filters.......................................................................................................................................... 6

Policies ....................................................................................................................................... 6

Adapters ..................................................................................................................................... 7

Summary ............................................................................................................................................ 8

For More Information ........................................................................................................................... 9

Request for Comments ...................................................................................................................... 9

Associated HP IP Quality of Service (IPQoS) documents........................................................................ 9

Summary of content (9 pages)

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Introduction to Differentiated Services (DiffServ) and HP-UX IPQoS What is Quality of Service (QoS)? ......................................................................................................... 2 Differentiated Services (DiffServ) ............................................................................................................ 2 Overview ........................................................................................................................................
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What is Quality of Service (QoS)? Many of today’s IP networks provide what is referred to as “Best Effort Service”. Delivery of an IP packet is accomplished without differentiating between the requirements of specific traffic flows such as voice, video, or data. Voice and video, for example, require minimal interruptions in packet flow to avoid jitter and delays during communication. Data, on the other hand, may only require that it reaches its destination within a reasonable timeframe.
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remaining types of traffic within a reasonable timeframe. Thus, there is no need to overprovision the network bandwidth or build a parallel network for VoIP traffic. Components of DiffServ The following sections discuss the DiffServ environment from general concepts to more specific information, including the role of HP-UX IPQoS in that environment.
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port numbers. Packets are grouped into traffic flows based on BA or MF filters to be forwarded in a pre-defined forwarding manner. In our example, the XYZ Corporation will want to filter its VoIP traffic using one or more fields in the IP header. These fields may include source/destination addresses, ports, or protocol id. The VoIP application at XYZ uses the Real-Time Transport Protocol (RTP) to send data.
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IPv6 Header Version Flow Label Traffic Class Payload Length Next Header Hop Limit Source Address… 128 bits Destination Address… 128 bits (Note: the above diagram is not to scale.) Shaping and Dropping (Policing) Shaping is the process of delaying packets so that the traffic stream is brought into conformance with the specified profile. For example, a specific traffic stream may be allowed 30% of the bandwidth but, if left unchecked, could consume 50% of the bandwidth.
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HP-UX IPQoS HP-UX IPQoS conforms to IETF standards for the Differentiated Services architecture of QoS and provides traffic classification and conditioning. HP-UX IPQoS provides host-based functionality for outbound packets. It includes an administration tool, ipqosadmin, which can be used for loading, verifying, and unloading of configuration files as well as provide state and statistical information.
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Adapters Adapter blocks assign policies to specific configured adapters (NICs) on the system. XYZ Configuration XYZ has determined that they’ll reserve at least 40% of the bandwidth for VoIP communications. The remaining bandwidth will be used for all other communication.
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Summary Differentiated Services (also referred to as DiffServ or DS) provides a network administrator with the ability to classify network traffic by specific flows and to apply a traffic policy to each of those flows. Multimedia applications, for example, may need dedicated higher bandwidth to avoid jitter and delay to ensure seamless communications. Other types of traffic may have bandwidth requirements as well and would benefit from DiffServ.
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For More Information Request for Comments Request for Comments (RFCs) can be found at www.ietf.