rfc3421.Select and Sort Extensions for the Service Location Protocol (SLP)

Internet RFC/STD/FYI/BCP ArchivesRFC1242[ Index | Search | What's New | Comments | Help ]Network Working Group S. Bradner, Editor Request for Comments: 1242 Harvard University July 1991Benchmarking Terminology for Network Interconnection DevicesStatus of this MemoThis memo provides information for the Internet community. It does not specify an Internet standard. Distribution of this memo isunlimited.AbstractThis memo discusses and defines a number of terms that are used indescribing performance benchmarking tests and the results of suchtests. The terms defined in this memo will be used in additionalmemos to define specific benchmarking tests and the suggested format to be used in reporting the results of each of the tests. This memo is a product of the Benchmarking Methodology Working Group (BMWG) of the Internet Engineering Task Force (IETF).1. IntroductionVendors often engage in "specsmanship" in an attempt to give theirproducts a better position in the marketplace. This usually involves much "smoke & mirrors" used to confuse the user. This memo andfollow-up memos attempt to define a specific set of terminology and tests that vendors can use to measure and report the performancecharacteristics of network devices. This will provide the usercomparable data from different vendors with which to evaluate these devices.2. Definition formatTerm to be defined. (e.g., Latency)Definition:The specific definition for the term.Discussion:A brief discussion about the term, it's applicationand any restrictions on measurement procedures.Measurement units:The units used to report measurements of thisterm, if applicable.Issues:List of issues or conditions that effect this term.See Also:List of other terms that are relevant to the discussion of this term.3. Term definitions3.1 Back-to-backDefinition:Fixed length frames presented at a rate such that there is the minimum legal separation for a given mediumbetween frames over a short to medium period of time,starting from an idle state.Discussion:A growing number of devices on a network can producebursts of back-to-back frames. Remote disk serversusing protocols like NFS, remote disk backup systemslike rdump, and remote tape access systems can beconfigured such that a single request can result ina block of data being returned of as much as 64K octets. Over networks like ethernet with a relatively small MTU this results in many fragments to be transmitted. Since fragment reassembly will only be attempted if allfragments have been received, the loss of even onefragment because of the failure of some intermediatenetwork device to process enough continuous frames can cause an endless loop as the sender repetitivelyattempts to send its large data block.With the increasing size of the Internet, routingupdates can span many frames, with modern routers able to transmit very quickly. Missing frames of routinginformation can produce false indications ofunreachability. Tests of this parameter are intendedto determine the extent of data buffering in thedevice.Measurement units:Number of N-octet frames in burst.Issues:See Also:3.2 BridgeDefinition:A system which forwards data frames based on information in the data link layer.Discussion:Measurement units:n/aIssues:See Also:bridge/router (3.3)router (3.15)3.3 bridge/routerDefinition:A bridge/router is a network device that can selectively function as a router and/or a bridge based on theprotocol of a specific frame.Discussion:Measurement units:n/aIssues:See Also:bridge (3.2)router (3.15)3.4 Constant LoadDefinition:Fixed length frames at a fixed interval time.Discussion:Although it is rare, to say the least, to encountera steady state load on a network device in the realworld, measurement of steady state performance maybe useful in evaluating competing devices. Theframe size is specified and constant. All deviceparameters are constant. When there is a checksumin the frame, it must be verified.Measurement units:n/aIssues:unidirectional vs. bidirectionalSee Also:3.5 Data link frame sizeDefinition:The number of octets in the frame from the first octet following the preamble to the end of the FCS, ifpresent, or to the last octet of the data if thereis no FCS.Discussion:There is much confusion in reporting the framesizes used in testing network devices or networkmeasurement. Some authors include the checksum,some do not. This is a specific definition for usein this and subsequent memos.Measurement units:octetsIssues:See Also:3.6 Frame Loss RateDefinition:Percentage of frames that should have been forwardedby a network device under steady state (constant)load that were not forwarded due to lack ofresources.Discussion:This measurement can be used in reporting theperformance of a network device in an overloadedstate. This can be a useful indication of how adevice would perform under pathological networkconditions such as broadcast storms.Measurement units:Percentage of N-octet offered frames that are dropped. To be reported as a graph of offered load vs frame loss.Issues:See Also:overhead behavior (3.11)policy based filtering (3.13)MTU mismatch behavior (3.10)3.7 Inter Frame GapDefinition:The delay from the end of a data link frame as defined in section 3.5, to the start of the preamble of thenext data link frame.Discussion:There is much confusion in reporting the betweenframe time used in testing network devices. Thisis a specific definition for use in this and subsequent memos.Measurement units:Time with fine enough units to distinguish between2 events.Issues:Link data rate.See Also:3.8 LatencyDefinition:For store and forward devices:The time interval starting when the last bit of theinput frame reaches the input port and ending whenthe first bit of the output frame is seen on theoutput port.For bit forwarding devices:The time interval starting when the end of the firstbit of the input frame reaches the input port andending when the start of the first bit of the outputframe is seen on the output port.Discussion:Variability of latency can be a problem.Some protocols are timing dependent (e.g., LAT and IPX). Future applications are likely to be sensitive tonetwork latency. Increased device delay can reducethe useful diameter of net. It is desired toeliminate the effect of the data rate on the latencymeasurement. This measurement should only reflect the actual within device latency. Measurements should betaken for a spectrum of frame sizes without changingthe device setup.Ideally, the measurements for all devices would be fromthe first actual bit of the frame after the preamble. Theoretically a vendor could design a device thatnormally would be considered a store and forwarddevice, a bridge for example, that begins transmitting a frame before it is fully received. This type ofdevice is known as a "cut through" device. Theassumption is that the device would somehow invalidate the partially transmitted frame if in receiving theremainder of the input frame, something came up that the frame or this specific forwarding of it was inerror. For example, a bad checksum. In this case,the device would still be considered a store andforward device and the latency would still befrom last bit in to first bit out, even though thevalue would be negative. The intent is to treatthe device as a unit without regard to the internalstructure.Measurement units:Time with fine enough units to distinguish between2 events.Issues:See Also:link speed mismatch (3.9)constant load (3.4)back-to-back (3.1)policy based filtering (3.13)single frame behavior (3.16)3.9 Link Speed MismatchDefinition:Speed mismatch between input and output data rates.Discussion:This does not refer to frame rate per se, it refers to the actual data rate of the data path. For example,an Ethernet on one side and a 56KB serial link on the other. This is has also been referred to as the "fire hose effect". Networks that make use of serial links between local high speed networks will usually havelink speed mismatch at each end of the serial links.Measurement units:Ratio of input and output data rates.Issues:See Also:constant load (3.4)back-to-back (3.1)3.10 MTU-mismatch behaviorDefinition:The network MTU (Maximum Transmission Unit) of theoutput network is smaller than the MTU of the inputnetwork, this results in fragmentation.Discussion:The performance of network devices can be significantly affected by having to fragment frames.Measurement units:Description of behavior.Issues:See Also:3.11 Overhead behaviorDefinition:Processing done other than that for normal data frames.Discussion:Network devices perform many functions in additionto forwarding frames. These tasks range from internal hardware testing to the processing of routinginformation and responding to network managementrequests. It is useful to know what the effect ofthese sorts of tasks is on the device performance.An example would be if a router were to suspendforwarding or accepting frames during the processingof large routing update for a complex protocol likeOSPF. It would be good to know of this sort ofbehavior.Measurement units:Any quantitative understanding of this behavior is by the determination of its effect on other measurements.Issues:bridging and routing protocolscontrol processingicmpip options processingfragmentationerror processingevent logging/statistics collectionarpSee Also:policy based filtering (3.13)3.12 Overloaded behaviorDefinition:When demand exceeds available system resources.Discussion:Devices in an overloaded state will lose frames. The device might lose frames that contain routing orconfiguration information. An overloaded state isassumed when there is any frame loss.Measurement units:Description of behavior of device in any overloadedstates for both input and output overload conditions.Issues:How well does the device recover from overloaded state? How does source quench production effect device?What does device do when its resources are exhausted? What is response to system management in overloadedstate?See Also:3.13 Policy based filteringDefinition:Filtering is the process of discarding receivedframes by administrative decision where normaloperation would be to forward them.Discussion:Many network devices have the ability to beconfigured to discard frames based on a numberof criteria. These criteria can range from simplesource or destination addresses to examiningspecific fields in the data frame itself.Configuring many network devices to performfiltering operations impacts the throughputof the device.Measurement units:n/aIssues:flexibility of filter optionsnumber of filter conditionsSee Also:3.14 Restart behaviorDefinition:Reinitialization of system causing data loss.Discussion:During a period of time after a power up orreset, network devices do not accept and forwardframes. The duration of this period of unavailabilitycan be useful in evaluating devices. In addition,some network devices require some form of resetwhen specific setup variables are modified. If thereset period were long it might discourage networkmanagers from modifying these variables on productionnetworks.Measurement units:Description of device behavior under various restartconditions.Issues:Types:power onreload software imageflush port, reset buffersrestart current code image, without reconfurationUnder what conditions is a restart required?Does the device know when restart needed (i.e., hungstate timeout)?Does the device recognize condition of too frequentauto-restart?Does the device run diagnostics on all or some resets?How may restart be initiated?physical interventionremote via terminal line or login over networkSee Also:3.15 RouterDefinition:A system which forwards data frames based oninformation in the network layer.Discussion:This implies "running" the network level protocolrouting algorithm and performing whatever actionsthat the protocol requires. For example, decrementingthe TTL field in the TCP/IP header.Measurement units:n/aIssues:See Also:bridge (3.2)bridge/router (3.3)3.16 Single frame behaviorDefinition:One frame received on the input to a device.Discussion:A data "stream" consisting of a single frame canrequire a network device to do a lot of processing.Figuring routes, performing ARPs, checkingpermissions etc., in general, setting up cache entries. Devices will often take much more time to process asingle frame presented in isolation than it would ifthe same frame were part of a steady stream. Thereis a worry that some devices would even discard a single frame as part of the cache setup procedure under theassumption that the frame is only the first of many.Measurement units:Description of the behavior of the device.Issues:See Also:policy based filtering (3.13)3.17 ThroughputDefinition:The maximum rate at which none of the offered framesare dropped by the device.Discussion:The throughput figure allows vendors to report asingle value which has proven to have use in themarketplace. Since even the loss of one frame in adata stream can cause significant delays whilewaiting for the higher level protocols to time out,it is useful to know the actual maximum datarate that the device can support. Measurements should be taken over a assortment of frame sizes. Separatemeasurements for routed and bridged data in thosedevices that can support both. If there is a checksum in the received frame, full checksum processing mustbe done.Measurement units:N-octet input frames per secondinput bits per secondIssues:single path vs. aggregateloadunidirectional vs bidirectionalchecksum processing required on some protocolsSee Also:frame loss rate (3.6)constant load (3.4)back-to-back (3.1)4. AcknowledgementsThis memo is a product of the IETF BMWG working group:Chet Birger, Coral NetworksScott Bradner, Harvard University (chair)Steve Butterfield, independant consultantFrank Chui, TRWPhill Gross, CNRIStev Knowles, FTP Software, Inc.Mat Lew, TRWGary Malkin, FTP Software, Inc.K.K. Ramakrishnan, Digital Equipment Corp.Mick Scully, Ungerman BassWilliam M. Seifert, Wellfleet Communications Corp.John Shriver, Proteon, Inc.Dick Sterry, MicrocomGeof Stone, Network Systems Corp.Geoff Thompson, SynOpticsMary Youssef, IBMSecurity ConsiderationsSecurity issues are not discussed in this memo.Author's AddressScott BradnerHarvard UniversityWilliam James Hall 123233 Kirkland StreetCambridge, MA 02138Phone: (617) 495-3864EMail: SOB@Or, send comments to: bmwg@.[ Index | Search | What's New | Comments | Help ] Comments/Questions about this archive ? Send mail to rfc-admin@。

SIP会话定时器摘要本文定义了SIP的一种扩展机制，该扩展通过发送一个re-INVITE或UPDATE请求来周期性的更新SIP会话。

通过更新用户代理和代理服务器可以判断会话是否还活动着。

该扩展定义了两个新的头字段：Session-Expires，用来传达会话的寿命，Min-SE，用来传达会话定时器允许的最小值。

引论会话初始化协议（SIP）并没有为所建立的会话定义存活机制。

尽管用户代理可以通过会话特定的机制判断会话是否超时，但是代理服务器却做不到这点。

如此一来，有状态代理服务器有时会无法判断会话是否还是活动的。

例如，当一个用户代理在会话结束时发送BYE消息失败，或者由于网络问题BYE消息丢失，有状态代理服务器将不会知道会话已经结束。

在这种情况下，有状态代理服务器将保持呼叫的状态并且无法知道呼叫状态信息何时失效。

为了解决这个问题，本扩展为SIP会话定义了一种存活机制。

用户代理周期性的发送re-INVITE或UPDATE请求（参见会话更新请求）用来保持会话的活动。

会话更新请求的间隔通过本文定义的协商机制决定。

如果在间隔内没有收到会话更新请求，该会话被认为已经终止。

用户代理会发送一个BYE消息，有状态代理服务器则将该呼叫的所有状态移除。

这种更新机制还有一些附加的应用。

一个用户代理和一个代理服务器出于同一个目的，都想知道会话是否还活动着，可以在用户代理上作出判断而无需使用SIP层的机制；对于音频会话，周期性的RTCP报文充当着会话活动的指示。

无论如何，将SIP会话的活动指示从特定会话的细节中分离出来是合理的。

会话定时器的另一个应用是SIP网络地址转换（NAT）应用层网关（ALG）的构造。

内嵌在NAT中的ALG需要在呼叫持续期间维护状态。

最终这个状态必须被删除。

依赖于发送BYE 消息来触发状态的删除，除了状态已经不可靠之外，还引入了潜在的拒绝服务攻击。

本文提供了一种SIP扩展机制用于定义会话期满机制。

通过re-INVITE或UPDATE的周期性更新被用来保持会话的活动性。

中国移动通信企业标准QB-╳╳-╳╳╳-╳╳╳╳中国移动统一D P I设备技术规范-L T E信令采集解析服务器接口规范Te c h n i c a l S p e c i f i c a t i o n o f D e e p P a c k e tI n s p e c t i o n E q u i p m e n t f o r C M C C(L T E S i g n a l l i n g C o l l e c t i o n S e r v e r I n t e r f a c eP a r t)版本号：2.0.9╳╳╳╳-╳╳-╳╳发布╳╳╳╳-╳╳-╳╳实施中国移动通信集团公司发布目录1 范围 (3)2 规范性引用文件 (3)3 术语、定义和缩略语 (4)4 接口在网络中的位置 (6)5 LTE接口XDR数据构成方式 (8)5.1. XDR编号与上报要求 (8)6 Uu接口XDR数据结构 (9)6.1. 公共信息 (9)6.2. Uu接口信息 (11)6.3. Uu接口Keyword 1字段定义 (15)6.4. Uu接口事件流程开始/结束标识 (17)7 X2接口XDR数据结构 (17)7.1. 公共信息 (17)7.2. X2接口信息 (17)7.3. X2接口事件流程开始/结束标识 (23)8 UE_MR XDR数据结构 (23)8.1. 公共信息 (23)8.2. UE_MR信息 (23)9 Cell_MR XDR数据结构 (27)9.1. 公共信息 (27)9.2. Cell_MR信息 (27)10 S1-MME接口XDR数据结构 (28)10.1. 公共信息 (28)10.2. S1-MME接口信息 (28)10.3. S1-MME接口Keyword 1字段定义 (38)10.4. S1-MME接口Keyword 2字段定义 (40)10.5. S1-MME接口事件流程开始/结束标识 (47)11 S1-U接口XDR数据结构 (47)12 S6a 接口XDR数据结构 (47)12.1. 公共信息 (47)12.2. S6a接口信息 (48)13 S10、S11接口XDR数据结构 (50)13.1. 公共信息 (50)13.2. S10、S11接口信息 (50)14 S5/S8-C接口XDR数据结构 (57)14.1. 公共信息 (57)14.2. S5/S8-C接口信息 (57)15 SGs接口XDR数据结构 (61)15.1. 公共信息 (61)15.2. SGs接口信息 (62)16 Gn-C接口XDR数据结构 (65)16.1. 公共信息 (65)16.2. Gn-C接口信息 (65)17 基于XDR的原始码流上报 (68)17.1. 原始码流上报功能 (68)17.2. 基于XDR上报原始码流的格式 (68)17.3. 按帧封装的原始码流要求 (69)17.3.1. 通用包头格式 (70)17.3.2. 专用包头格式 (71)17.3.3. 原始数据 (71)18 接口协议 (71)18.1. SDTP协议概述 (72)18.2. 消息类型 (73)18.3. 消息结构 (74)18.4. 连接管理流程 (75)18.5. 连接管理消息 (77)18.5.1. 版本协商verNego (77)18.5.1.1. 请求 (77)18.5.1.2. 应答 (77)18.5.2. 链路认证linkAuth (78)18.5.2.1. 请求 (78)18.5.2.2. 应答 (79)18.5.3. 链路检测linkCheck (80)18.5.3.1. 请求 (80)18.5.3.2. 应答 (80)18.5.4. 链路数据发送校验linkDataCheck (80)18.5.4.1. 请求 (80)18.5.4.2. 应答 (81)18.5.5. 链路释放linkRel (82)18.5.5.1. 请求 (82)18.5.5.2. 应答 (82)18.6. 数据传输消息 (82)18.6.1. XDR数据传输notifyXDRData (83)18.6.1.1. 请求 (83)18.6.1.2. 应答 (83)18.6.2. XDR对应原始码流传输XDRRawDataSend (83)18.6.2.1. 请求 (83)18.6.2.2. 应答 (83)19 编制历史 (84)附录A：Uu/X2接口XDR事件流程和关键信令点 (85)附录B：S1-MME接口XDR事件流程和关键信令点 (85)前言本规范对中国移动网内使用的深度包检测（DPI）设备的功能和性能提出要求，是部署统一DPI设备需要遵从的技术文件。

VDX 674 0 T-1G Sw it ch
The VDX 674 0 T-1G ( Fig ure 3) offers 4 8 10 0 0 BA SE-T p ort s and t w o 4 0 Gb E QSFP+ p ort s. Each 4 0 Gb E p ort can b e b roken out int o four ind ep end ent 10 Gb E SFP+ p ort s, p rovid ing an ad d it ional eig ht 10 Gb E SFP+ p ort s for up link. A ll 4 8 10 0 0 BA SE-T p ort s can b e up g rad ed t o 4 8 10 GBA SE-T p ort s via t he Cap acit y on Dem and (CoD) soft w are license. Tw o 4 0 Gb E p ort s are enab led as p art of t he b ase license. The ad d it ional t w o 4 0 Gb E p ort s can b e up g rad ed via t he Port s on Dem and ( PoD) soft w are license.
- Meet s t od ay?s ap p licat ion d em and s w it h high perform ance and low latency
- Delivers line-rate t hroughput for all p ort s and p acket sizes
Dat a Sheet