3GPP PS

先从编号说起,3GPP大部分协议是AA.BBB-CCC类型的编号.其中A,B,C都代表单个数字 .
协议命名的规则为AA.BBB-CCC,其中CCC说明协议的版本.例如820大致说的就是协议的R8版本.640含义为协议的R6版本.后面的数字为小版本,不用太关注.AA.BBB,说明的是协议号,自我感觉,没什么规律.21.XXX-35.XXX用的较多,其他的没感觉.
现在协议已经从Rel1到Rel9.但协议中,网络的基本架构从R5以来没怎么变过.在R3中划分了MSC,HLR等网元在R5中进一步把MSC划分为软交换和MGW两个部分,控制和承载分离.在R6中引入了IMS内容(记不清了,大家考证一下).现在最新的版本中加入了LTE的标准.

其中有些是GSM协议,有些是UMTS的协议.
GSM协议的列表可以参考01.01 / 41.101.
UMTS 协议的列表可以参考21.101.

当然,有些协议及属于GSM也属于UMTS.
在第二部分的开头扯一下经常提到的 3G,4G,5G… 之争 . 以至于 NG 之争 .
当我没有迈入通信行业时 , 当时的想法极为可笑 : 认为要 3G 的网络 , 就不能要 2G 的网络 .3G 的业务真是神乎其神 . 因此 2G 也就暂时不要发展了 . 等着 3G 的到来就行了 .
但从标准中看来 , 不同的技术时代 , 没有绝对的技术之争 . 没有绝对的技术壁垒 . 有的只是业务能力的不同 . 原有网络的网元 (2G 中的旧有设备 ) 完全可以在新的网络架构下重复利用 ( 新的 3G 的网络 ). 旧设备的重用可以带来很多的好处 , 如 , 减少建网成本 , 增加网络 KPI, 增加运营商网络的无缝覆盖 . 旧设备的问题仅仅是业务提供能力 (2G) 与新的设备 (3G) 有所欠缺 . 但这个缺点也没有太大关系 . 毕竟 3G 网络初期 , 一般是热点覆盖 , 而不会是全网覆盖 . 热点区域使用新设备 , 旧设备 (2G) 同样可以使用 . 没有必要因为缺少某中业务 , 而将旧设备 (2G) 完全搬掉 . 尤其是在当前 3G 网络没有出现杀手级应用的情况下 .
为何这样说?
在3GPP中从R1版本到现在的R8版本,在技术上各个版本都是一脉相承的.纵观整个3GPP标准,每一个版本都继承了原来的网元,只不过增加了新网元支持新功能.或将原有网元的功能细化.
如3GPP中的大纲性协议23.002.在发展过程中CS域的网元MSC,由单一形态分割成MSC和MGW,实现控制和承载分离.而后为了适应全网IP化,为了发展下一代网络.提出了IMS.但MSC和MGW也平滑演进为MGCP和IM-MGW.旧有设备的利旧,协议的平滑演进,一直都是新标准必须满足的需求.旧有网络中的网元完全是可以在新的网络中完成互联的.仅仅是功能有点Weak而已.
2G与3G之争,世上本无事,庸人自扰之…
=========================================================================
整个协议下载下来有4G左右,XX多个文件,如此复杂,庞大的协议族如何阅读,从哪里阅读?我们将一起找到一个入口.
通过协议列表21.101.我们找到了23.002.该协议说明了电信网络的整体架构,

TS

23.002

Network architecture

S2

Yes

2007-06-07

Yes

现在GSM UMTS甚至是固网NGN中的网元都基本上以该文档中的术语命名.如MSC, A口 Iu_CS Iu_PS口.等.耳熟能详.都是在这个文档中定义的.
我们先看一下网元的定义吧.下面会大量摘抄协议原文,因为除了协议描述,我实在找不到更适合的语言来描述网元的定义了.我就仿照<深入浅出MFC>中对代码的解释,来试着将协议文本来个庖丁解牛吧.如果功力不到还请大家见谅.
在协议中定义的网元都是逻辑实体,而不是物理实体,这点需要同学们注意.例如VLR和MSC在协议中是两个逻辑实体,但现实情况下,大部分的厂商都把VLR的功能放在MSC里面.这样一个物理实体MSC就同时提供两个逻辑实体的功能.这点需要大家注意.另一方面同一个物理实体在不同的情况下可能扮演不同的逻辑实体,如MSC同时支持VMSC功能和GMSC功能,那么我们就说这个MSC是V G合一的.
一句话,逻辑实体和物理实体是两个概念,一个描述逻辑功能,一个是物理设备.两者既有区别,也有联系.一个逻辑功能可以有不同的物理实体来实现,一个物理设备也可以同时实现若干个协议中定义的逻辑功能/实体.
第1章
Scope
第2章
References

略过…
第三章 Definitions and abbreviations
Public Land Mobile Network (PLMN)//PLMN定义
A Public Land Mobile Network (PLMN) is established and operated by an admnistration or Recognized Private Operating Agency (RPOA) for the specific purpose of providing land mobile telecommunications service services to the public. A PLMN may be regarded as an extension of networks (e.g. ISDN, corporate and public PDNs, etc); it is a collection of MSCs areas in CS domain and SGSN areas for GPRS and SGSN or MME areas for EPC in PS domain within a common numbering plan (e.g. same National Destination Code) and a common routing plan. The MSCs are the functional interfaces between the fixed networks and a PLMN for call set-up in CS domain. The GGSN and the SGSN are the functional interfaces between the fixed networks and a PLMN for packet transmission in GPRS PS domain. In case of EPC PS Domain, the PDN-GW, Serving-GW and the SGSN and the MME are the functional interfaces between the fixed networks and a PLMN for packet transmission.
Functionally the PLMNs may be regarded as independent telecommunications entities even though different PLMNs may be interconnected through the ISDN/PSTN and PDNs for forwarding of calls or network information. A similar type of interconnection may exist for the interaction between the MSCs/SGSNs/MMEs of one PLMN.
红色部分描述的很清楚.就不多说了.
Core Network (CN) and Access Network (AN) //网络分为核心网和接入侧.
The PLMN infrastructure is logically divided into a Core Network (CN) and an Access Network (AN) infrastructures, as defined in TS 23.101 [11a] and TS 23.110 [11b]. The CN is logically divided into a CS domain, a PS domain and an IM subsystem, as defined in next clause. The AN are GERAN (also called BSS for GSM), UTRAN (also called RNS), E-UTRAN, as defined in clause "The Access Network".
Circuit Switched (CS) and Packet Switched (PS) Domains //核心网又分为PS(数据业务)和CS(语音业务)两部分

The CN is constituted of a Circuit Switched (CS) domain and a Packet Switched (PS) domain (which includes GPRS and EPC). These two domains differ by the way they support user traffic, as explained below.
These two domains are overlapping, i.e. they contain some common entities. A PLMN can implement only one domain or both domains.
CS Domain//核心网CS部分定义.
The CS domain refers to the set of all the CN entities offering "CS type of connection" for user traffic as well as all the entities supporting the related signalling. A "CS type of connection" is a connection for which dedicated network resources are allocated at the connection establishment and released at the connection release.
The entities specific to the CS domain are: MSC, GMSC, VLR. All the other CN entities defined in clause 4 "The basic entities of the mobile system" and not defined as PS domain specific entities (see following clause) are common to the CS and to the PS domains. In case of E-UTRAN access, there is no support for CS Domain.
PS Domain//核心网PS部分定义.
The PS domain refers to the set of all the CN entities offering "PS type of connection" for user traffic as well as all the entities supporting the related signalling. A "PS type of connection" transports the user information using autonomous concatenation of bits called packets: each packet can be routed independently from the previous one.
The entities specific to the PS domain are the GPRS specific entities, i.e. SGSN and GGSN and EPS specific entities, i.e. PDN GW, S-GW, MME, SGSN. All the other CN entities defined in clause "4 The basic entities of the mobile system" and not defined as CS domain specific entities (see previous clause) are common to the CS and to the PS domains.
IP Multimedia subsystem (IMS)//IMS部分的定义,大家都认为IMS,移动固网融合,神奇无比,实际上,只是一个小小的subsystem.不是很复杂,不要害怕.
The IM subsystem comprises all CN elements for provision of IP multimedia services comprising audio, video, text, chat, etc. and a combination of them delivered over the PS domain. The entities related to IMS are CSCF, MGCF, MRF, etc. as defined in the stage 2 of the IM subsystem TS 23.228 [34]. See TS 22.228 [27] for some service examples of IMS.