Calidad en los servicios cisco

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Cisco IOS Software Quality of Service

Michael Lin Product Manager IOS QoS, nBAR Network Software & Systems Technology Group

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© 2007 Cisco Systems, Inc. All rights reserved.

1

What Is Quality of Service?
To the end user
User’s perception that their applications are performing properly Voice - No drop calls, no static Video - High quality, smooth videoData - Rapid response time

To The Network Manager
Maximize network bandwidth utilization while meeting performance expectations Control Delay - The finite amount of time it takes a packet to reach the receiving endpoint Jitter -The difference in the end-to-end delay between packets. Packet Loss - relative measure of the number of packets that were not received compared to the total number ofpackets transmitted.
Session ID Presentation_ID © 2007 Cisco Systems, Inc. All rights reserved.

2

Why Enable QoS?
Security Quality of Service • Optimize bandwidth utilization for Video, Voice & Data apps • Drives productivity by enhancing servicelevels to missioncritical applications • Helps maintain network availability in the event of DoS/worm attacks Network Availability
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© 2007 Cisco Systems, Inc. All rights reserved.

3

Quality of Service Operations How does it work & essential elements
CLASSIFICATION AND MARKING QUEUEING AND DROPPING POST-QUEUING OPERATIONS

Classification & Marking:
The first element to a QoS policy is to classify/identify the traffic that is to be treated differently. Following classification, marking tools can set anattribute of a frame or packet to a specific value.

Policing:
Determine whether packets are conforming to administratively-defined traffic rates and take action accordingly. Such action could include marking, remarking or dropping a packet.

Scheduling (including Queuing & Dropping):
Scheduling tools determine how a frame/packet exits a device. Queueing algorithms are activated only when adevice is experiencing congestion and are deactivated when the congestion clears.

Link Specific Mechanisms (Shaping, Fragmentation, Compression, Tx Ring)
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Offers network administrators tools to optimize link utilization
© 2007 Cisco Systems, Inc. All rights reserved.

4

QoS Deployment Principles

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© 2007 Cisco Systems, Inc. Allrights reserved.

5

How Is QoS Optimally Deployed?
1. Strategically define the business objectives to be achieved via QoS 2. Analyze the service-level requirements of the various traffic classes to be provisioned for 3. Design and test the QoS policies prior to productionnetwork rollout 4. Roll-out the tested QoS designs to the production-network in phases, during scheduled downtime 5.Monitor service levels to ensure that the QoS objectives are being met
Session ID Presentation_ID © 2007 Cisco Systems, Inc. All rights reserved.

6

General QoS Design Principles
Clearly define the organizational objectives
Protect voice? Video? Data? DoS/worm mitigation?

Assign as few applications as possible to be treated as “mission-critical” Seek executive endorsement of the QoSobjectives prior to design and deployment Determine how many classes of traffic are required to meet the organizational objectives
More classes = More granular service-guarantees

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© 2007 Cisco Systems, Inc. All rights reserved.

7

How Many Classes of Service Do I Need?
Example Strategy for Expanding the Number of Classes of Service over Time

4/5 Class Model8 Class Model Voice

11 Class Model Voice Interactive-Video Streaming Video Call Signaling IP Routing Network Management Mission-Critical Data Transactional Data Bulk Data Best Effort Scavenger
8

Realtime Video Call Signaling Call Signaling Network Control Critical Data Critical Data Bulk Data Best Effort Scavenger Time Best Effort Scavenger

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© 2007 Cisco...
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