SLA-服务等级协议

1、SLA效力等级协议ISP的锐利武器和必由之路广东省电信科学技术研讨院多媒体研讨事业部陈文革博士后.内容提要什么是SLA?国内外SLA的开展动态电信开展SLA运用的战略讨论小结.一、什么是SLA?A Service Level Agreement is a contract between a provider and a customer that guarantees specific levels of performance and reliability at a certain costfine print fine print fine print fine print fine

2、print fine print fine print fine print fine print fine print游览社 “八菜一汤 四星级饭店 空调大巴.SLA的分类Carrierbackbone network providerAvailabilityRound trip delayPacket lossASP Access services providerDialup success rateAccess rateData CenterHosting, EC, ASP service providerAvailabilityService response time( for c

3、ustomers).SLA的特点SLA是对客户最关怀的效力质量的承诺，而如何实现和保证效力质量不是SLA的范畴。邮局送信的例子10M/100M端口、机房条件等的承诺？SLA与通常所说的QOS是有区别的QOS普通针对网络而言，而SLA是用户感知的效力质量，QOS是实现和保证SLA的一个环节。比如网络畅通但是效力器拥塞！IP网络统计复用、流量突发的特点导致SLA也只能以一种统计的方法描画平均，最大最小；某一性能目的大于某一商定值得概率大于98%。讲等级Level)才有实践意义，才可以操作。 .SLA Configuration SLA Name SLA Type Expression SLO Ti

4、meSpec Compliance Percentage Contract DateSelectedFrom ServiceModelMeasurementThreshold Spec.TimeSpec.San Diego Pop PVC JitterThreshold Spec.TimeSpec.SLO1TypeCondition Boundary UnitofMeas GracePeriod GPUnitofMeas. SeverityVariable Static=Envelope100MillisecondsSecondsMinutesHoursDaysMillisecondsSeco

5、ndsMinutesHoursDaysWarningMinorMajorCritical3ThresholdSpec2Conformance Operating Operating Period Days HoursHourDayWeekMonthYearMon-FriWeekendsn/a8:00am - 5:00pm6:00pm - 11:00pmn/aSLA TimeSpec3ExpressionsSD_Pop_Availability AND(SD_Pop_PVC_Jitter OR SD_Pop_PVC_SignalQuality)4100%98%80%SLASanDiego Pop

6、 PVC SLA CalendarAnniversary5 SLA的配置举例.Web Gold Report for Acme 28 SLA calculations were performed over the period Oct 1, 1999 12:00:00 AM - Oct 7, 1999 11:59:59 PM.16 were found compliant, 9 were found non-compliant, and 3 were undetermined. SLA Reports. 丈量实践效力性能参数 - Measure and record actual servi

7、ce transaction times - Measure full paths spanning network and servers - Better reflects customer or user experience 监视效力等级协议的符合情况 - Monitoring and management of the key components that provide the actual services - Provides an accurate view of actual service quality delivered as viewed by the custo

8、mer SLA报警和快速定位问题 - Provides preemptive warning of developing service problems - Enables rapid fault identification and isolation 提供SLA报告 - Performance graphs enable trend analysis for tracking asset utilization, future capacity planning, real-time service summaries - Customer reporting confirms QoSS

9、LA技术的主要内容.为什么SLA变得越来越重要竞争的需求比价钱转向比效力高速公路收费还是很多人走？新业务的需求(接入效力 to 商业效力Hosting, EC, ASP, VPN, IP Phone网络QOS/COS技术和SLA技术的逐渐成熟提供了技术保证。.Manage ever changing technologiesNNTPFTPSMTPHTMLRSVPChatDNSProxyMarginal ProfitabilityNeed differentiated value-added servicesEscalating ISP Challenges.Hiring Experienced

10、 EmployeesVolatile CustomerSatisfaction and ChurnQuickly resolve service related problems.二、国内外SLA技术的开展动态国际上从80年代后期开场SLA技术的研讨，90年代后期开场运用。目前SLA软件平台曾经相当成熟:Aigilents Firehunter、Concords Network Health ReportingLucents VitalSuiteKeynoteMatrix IQ.目前世界上最大的Internet骨干网络提供商根本上都为客户提供了实时/准实时的SLA，并在WEB上公开发布骨干网络

11、的SLA报告。AT&T, Sprint, UUNET, Qwest, Cable&Wireless越来越多的数据中心采用SLA技术提高市场竞争力和争取客户。例如世界上最大的Hosting公司Verio等第三方独立的SLA丈量和报告效力公司涌现KeynoteMIDS.AT&T SLA GlossaryBackbone AvailabilityThis is the overall availability of the network averaged over the month. Backbone Delay Delay (or latency) is the round-trip time

12、 for a small data packet to travel between two end points (source and destination city-pairs) in the network backbone. Delay affects ones perception of the response time of the network. Backbone Loss Loss is the percentage of packets lost in a data transaction. The measurement is a round trip one, m

13、ade by counting the packets sent between two city-pairs that do not return. Distance-Sensitive Thresholds Because the delay across the network is dependent on the distance the packets have to travel, our thresholds are set to be distance sensitive (based on the speed of light in fiber). The distance

14、s used are direct (crow-flies) miles. Modem Connect Success Rate It is the ability of the user clients dialup modem and the network modem to connect at any modem speed. The current average for Modem Connect Success Rate shown on the front page of the site are averaged over 24 hours over all Points o

15、f Presence (PoPs). .The Keynote Business 40 Internet Performance Index is the average response time of accessing and downloading the home pages of 40 important business Web Sites as measured Monday through Friday every 15 minutes between 6 am and noon Pacific time by those Keynote Perspective measur

16、ement computers that are located in metropolitan areas of the United States. .The Keynote Consumer 40 Internet Performance Index is the average response time of accessing and downloading the home pages of 40 important consumer web sites as measured Sunday through Saturday every hour between 5 am and

17、 9 pm Pacific time by Keynote Perspective measurement computers located in 8 major metropolitan areas.The automated measurement computers dial up via standard telephone lines and 56-Kbps modems to the local POPs (Points of Presence) of five leading ISPs: AT&T, Mindspring, Earthlink, MSN and AOL. .AG

18、ILENT TECHNOLOGIES FIREHUNTER/PRO SELECTED BY VERIO TO MONITOR SERVICELEVEL GUARANTEES FOR INTERNET SERVICESPALO ALTO, Calif., April 10, 1999 Agilent Technologies Inc. (NYSE: A) today announced that Verio Inc., the worlds largest Webhosting company, has selected Firehunter/PRO service assurance solu

19、tion to offer servicelevel guarantees for its Internet services.The initial implementation will be to measure performance across the Verio tier 1 network. Followup implementations will allow Verio to monitor and offer SLAs for other value-added services.三、电信开展SLA运用的战略讨论SLA是ISP的必然选择；SLA是一项复杂的系统工程，只能分

20、阶段逐渐实施；电信在SLA运用方面应尽早着手；当前实现SLA的前提在于尽快建立起全网的业务层管理系统；电信的SLA应该从网络效力入手，逐渐走向高层效力。.不论他愿不情愿，ISP特别是大ISP，都将不得不向用户做出效力质量的承诺，将效力价钱与效力质量挂起钩来，中国电信更是如此。国际上大ISP都曾经正式地起用了SLA，而且越来越成为ISP争夺挣脱客户特别是大客户的重要竞争手段；国内竞争的日益加剧，将迫使大的ISP首先走向SLA，中国电信也不例外。电子商务等商务运用对效力质量的迫切需求，推进ISP拿起SLA这个锐器。.2. SLA是一项复杂的系统工程，只能分阶段逐渐实施任何一项效力承诺的实现都建立在众多的要素根底之上，例如：能否拥有性能可控的网络取决于所采用的技术以及设计规划能否合理能否拥有强大的、覆盖全网的面向效力的业务层的管理系统这与Openview等面向网络的管理系统不是一回事能否建立了一整套效力质量的评价体系以及效力质量模型效力质量参数与相关众要素之间的依赖关系与美国相比，国内网络还处于大上快上的初期建立阶段，网络优化以及业务层管理还没有来得及得到足够的注重和投入，因此SLA的首要任务必需首先处理上述等问题。.3. 虽然SLA的实现有很多困难，但是电信还是应该尽早投入，并把它放在战略位置来抓。顾客是上帝，“上帝关怀的是所购买的效力，是效力质量，抓住了 SLA，就抓住