QoS Datasheet - DATA SHEET C isco IOS S oftware:...

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Cisco Systems Copyright © 2001 Cisco Systems, Inc. All Rights Reserved. Page 1 of 4 D ATA S HEET Cisco IOS Software: Quality-of-Service The Differentiated Services Model (DiffServ) The Challenge: Organizations delivering network-based services need powerful end-to-end solutions to effectively and predictably deliver the differing Quality-of-Service (QoS) requirements of voice, video, and data applications. Voice, for example, requires a small but assured amount of bandwidth, low delay, low jitter and low packet loss. A data application such as Fle transfer protocol (ftp) needs more bandwidth, but can tolerate the delay & jitter. The Solution: Cisco IOS ® software’s DiffServ offers application-level QoS and trafFc management in an architecture that incorporates mechanisms to control bandwidth, delay, jitter and packet loss. Cisco’s Diffserv complements Cisco’s IntServ offering by providing a more scalable architecture for end-to-end QoS. This scalability is achieved by the mechanisms controlling QoS at an aggregate level. Application trafFc can be categorized into multiple classes (aggregates), with QoS parameters deFned for each class. A typical arrangement would be to categorize trafFc into premium, gold, silver, bronze, and best-effort classes. Standards-based: Cisco IOS software’s DiffServ is fully compliant with the Internet Engineering Task ±orce (IET±) standards deFned in R±C 2474, R±C 2475, R±C 2597 and R±C 2598. Cisco’s solution leverages the new IET± deFnition of the IPv4 Type of Service (ToS) octet in the IP packet-header by utilizing the Differentiated Services Code Point (DSCP) Feld to classify packets into any of the 64 possible classes. Once the packets are classiFed IET±-deFned per-hop behaviors (PHBs) including assured forwarding (A±) and expedited forwarding (E±) are implemented using Cisco’s QoS tool chest. TrafFc that is characterized as E± will receive the lowest latency, jitter and assured bandwidth services which is suitable for applications such as VoIP. A± allows carving out the bandwidth between multiple classes in a network according to desired policies. As a value-add, Cisco’s implementation also allows you construction of user-deFned PHBs, beyond the scope of A± & E±. Thus, DSCP code points other than the ones reserved for A±, E±, and best effort service can be associated with an arbitrary PHB.
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This note was uploaded on 08/08/2011 for the course CISCO 1124 taught by Professor Jack during the Spring '11 term at American International.

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QoS Datasheet - DATA SHEET C isco IOS S oftware:...

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