📄 001_24.htm

📁 通讯类的标准。对要开发SS7的朋友有很大帮助的。（通讯协议）
💻 HTM
字号:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<!-- saved from url=(0059)http://www.chinagk.org/technology/IPTech/001/css/001_24.htm -->
<HTML><HEAD><TITLE>001_2_24</TITLE>
<META http-equiv=Content-Type content="text/html; charset=gb2312">
<STYLE type=text/css>.pg {
	LEFT: 0px; WIDTH: 635px; POSITION: absolute; TOP: 0px; HEIGHT: 983px
}
BODY {
	FONT-SIZE: 13px; COLOR: #000000; FONT-FAMILY: ""; BACKGROUND-COLOR: #ffffff
}
A {
	TEXT-DECORATION: none
}
.ps0 {
	LEFT: 38px; WIDTH: 552px; POSITION: absolute; TOP: 102px
}
.ps1 {
	LEFT: 38px; WIDTH: 143px; POSITION: absolute; TOP: 125px
}
.ps2 {
	LEFT: 229px; WIDTH: 174px; POSITION: absolute; TOP: 332px
}
.ps3 {
	LEFT: 65px; WIDTH: 529px; POSITION: absolute; TOP: 359px
}
.ps4 {
	LEFT: 38px; WIDTH: 556px; POSITION: absolute; TOP: 380px
}
.ps5 {
	LEFT: 38px; WIDTH: 556px; POSITION: absolute; TOP: 401px
}
.ps6 {
	LEFT: 38px; WIDTH: 556px; POSITION: absolute; TOP: 421px
}
.ps7 {
	LEFT: 38px; WIDTH: 563px; POSITION: absolute; TOP: 442px
}
.ps8 {
	LEFT: 38px; WIDTH: 556px; POSITION: absolute; TOP: 463px
}
.ps9 {
	LEFT: 38px; WIDTH: 552px; POSITION: absolute; TOP: 483px
}
.ps10 {
	LEFT: 38px; WIDTH: 556px; POSITION: absolute; TOP: 506px
}
.ps11 {
	LEFT: 38px; WIDTH: 464px; POSITION: absolute; TOP: 525px
}
.ps12 {
	LEFT: 65px; WIDTH: 530px; POSITION: absolute; TOP: 545px
}
.ps13 {
	LEFT: 38px; WIDTH: 556px; POSITION: absolute; TOP: 566px
}
.ps14 {
	LEFT: 38px; WIDTH: 556px; POSITION: absolute; TOP: 587px
}
.ps15 {
	LEFT: 38px; WIDTH: 556px; POSITION: absolute; TOP: 607px
}
.ps16 {
	LEFT: 38px; WIDTH: 554px; POSITION: absolute; TOP: 628px
}
.ps17 {
	LEFT: 38px; WIDTH: 556px; POSITION: absolute; TOP: 650px
}
.ps18 {
	LEFT: 38px; WIDTH: 557px; POSITION: absolute; TOP: 669px
}
.ps19 {
	LEFT: 38px; WIDTH: 478px; POSITION: absolute; TOP: 690px
}
.ps20 {
	LEFT: 65px; WIDTH: 530px; POSITION: absolute; TOP: 711px
}
.ps21 {
	LEFT: 38px; WIDTH: 556px; POSITION: absolute; TOP: 733px
}
.ps22 {
	LEFT: 38px; WIDTH: 556px; POSITION: absolute; TOP: 752px
}
.ps23 {
	LEFT: 38px; WIDTH: 556px; POSITION: absolute; TOP: 773px
}
.ps24 {
	LEFT: 38px; WIDTH: 563px; POSITION: absolute; TOP: 793px
}
.ps25 {
	LEFT: 38px; WIDTH: 557px; POSITION: absolute; TOP: 816px
}
.ps26 {
	LEFT: 38px; WIDTH: 557px; POSITION: absolute; TOP: 835px
}
.ps27 {
	LEFT: 65px; WIDTH: 76px; POSITION: absolute; TOP: 857px
}
.ps28 {
	LEFT: 65px; WIDTH: 537px; POSITION: absolute; TOP: 876px
}
.ps29 {
	LEFT: 38px; WIDTH: 555px; POSITION: absolute; TOP: 898px
}
.ps30 {
	LEFT: 53px; WIDTH: 259px; POSITION: absolute; TOP: 31px
}
.ps31 {
	LEFT: 548px; WIDTH: 43px; POSITION: absolute; TOP: 64px
}
.ps32 {
	LEFT: 338px; WIDTH: 34px; POSITION: absolute; TOP: 152px
}
.ps33 {
	LEFT: 312px; WIDTH: 85px; POSITION: absolute; TOP: 169px
}
.ps34 {
	LEFT: 209px; WIDTH: 43px; POSITION: absolute; TOP: 221px
}
.ps35 {
	LEFT: 118px; WIDTH: 43px; POSITION: absolute; TOP: 304px
}
.ps36 {
	LEFT: 476px; WIDTH: 21px; POSITION: absolute; TOP: 221px
}
.ps37 {
	LEFT: 477px; WIDTH: 26px; POSITION: absolute; TOP: 262px
}
.ps38 {
	LEFT: 469px; WIDTH: 43px; POSITION: absolute; TOP: 276px
}
.ps39 {
	LEFT: 311px; WIDTH: 26px; POSITION: absolute; TOP: 289px
}
.ps40 {
	LEFT: 303px; WIDTH: 43px; POSITION: absolute; TOP: 303px
}
.ft1 {
	FONT-SIZE: 11px; FONT-FAMILY: "Times New Roman",Times,serif
}
.ft2 {
	FONT-SIZE: 12px
}
.ft3 {
	FONT-WEIGHT: bold; FONT-SIZE: 37px; FONT-STYLE: italic; FONT-FAMILY: "Times New Roman",Times,serif
}
.ft4 {
	FONT-SIZE: 21px; COLOR: #000000; FONT-STYLE: italic; FONT-FAMILY: ""
}
.ft5 {
	FONT-SIZE: 9px; COLOR: #000000; FONT-FAMILY: "Times New Roman",Times,serif
}
.ft6 {
	FONT-SIZE: 11px; COLOR: #000000
}
.em0 {
	FONT-SIZE: 13px; FONT-FAMILY: ""
}
.em1 {
	FONT-SIZE: 11px; FONT-FAMILY: "Times New Roman",Times,serif
}
.em2 {
	FONT-WEIGHT: normal; FONT-SIZE: 13px; FONT-STYLE: italic
}
.em3 {
	FONT-SIZE: 10px; FONT-FAMILY: "Times New Roman",Times,serif
}
.em4 {
	FONT-SIZE: 13px; FONT-STYLE: italic; FONT-FAMILY: ""
}
.em5 {
	FONT-WEIGHT: normal; FONT-SIZE: 13px; FONT-STYLE: italic; FONT-FAMILY: ""
}
.im0 {
	LEFT: 39px; WIDTH: 562px; POSITION: absolute; TOP: 24px
}
.im1 {
	LEFT: 83px; WIDTH: 466px; POSITION: absolute; TOP: 149px
}
</STYLE>

<META content="MSHTML 6.00.2600.0" name=GENERATOR></HEAD>
<BODY>
<DIV class=pg></DIV><!-- bitmap and vector images are written here -->
<DIV class=im0><IMG height=64 src="001_24.files/left.jpg" width=564 
border=0></DIV>
<DIV class=im1><IMG height=168 src="001_24.files/001_2_24_2.jpg" width=466 
border=0></DIV><!-- text starts here --><SPAN class=ps0><NOBR>使用<SPAN 
class=em1>H.245</SPAN>介质信道路由来交换介质容量。图<SPAN class=em1>1-10</SPAN>中是<SPAN 
class=em1>H.225.0</SPAN>呼叫信令的可能方法及其对</NOBR></SPAN> <SPAN class=ps1><NOBR><SPAN 
class=ft1>H.245<SPAN class=em0>介质路由的影响。</SPAN></SPAN></NOBR></SPAN> <SPAN 
class=ps2><NOBR><SPAN class=ft2>图<SPAN class=em3>1-10 
&nbsp;&nbsp;H.323</SPAN>中的呼叫信令方法</SPAN></NOBR></SPAN> <SPAN 
class=ps3><NOBR>关守在域中是可选的，但是如果存在一个关守，建议使用它。域中没有<SPAN 
class=em1>GK</SPAN>意味着它并不</NOBR></SPAN> <SPAN class=ps4><NOBR>构成一个<SPAN 
class=em1>H.323</SPAN>区域。也就是说，一个域可以不是区域。即使存在<SPAN class=em1>GK<SPAN 
class=em0>，</SPAN></SPAN>呼叫建立过程中选择</NOBR></SPAN> <SPAN 
class=ps5><NOBR>的呼叫模型也可能是直接呼叫信令路由。这一决定是在进入请求过程中由端点作出的，端点</NOBR></SPAN> <SPAN 
class=ps6><NOBR>自身处理到来的呼叫。<SPAN 
class=em1>GK</SPAN>提供地址转换并在响应端点请求时为连接分配带宽。因此，以某种</NOBR></SPAN> <SPAN 
class=ps7><NOBR>方式在呼叫模型涉及的区域中保留一个<SPAN 
class=em1>GK</SPAN>非常重要，这样可以保证总的网络带宽使用可控。</NOBR></SPAN> <SPAN 
class=ps8><NOBR>在直接路由模型中，尽管端点之间的介质流可能不流经<SPAN class=em1>GK<SPAN 
class=em0>，</SPAN></SPAN>端点可以请求带宽随呼叫需要而</NOBR></SPAN> <SPAN 
class=ps9><NOBR>实时变化、<SPAN class=em1>GK</SPAN>可以协商并改变带宽分配。不管为<SPAN 
class=em1>H.225.0</SPAN>选择哪种呼叫信令路由模型，使用</NOBR></SPAN> <SPAN 
class=ps10><NOBR><SPAN class=ft1>H.245<SPAN 
class=em0>的介质信令通常是直接的，特例情况是通过</SPAN>MCU<SPAN 
class=em0>的桥路会话。直接路由在延迟方面有</SPAN></SPAN></NOBR></SPAN> <SPAN 
class=ps11><NOBR>重大的性能优点以及健壮性，因为关守在实际平台中可能是故障发生的地方。</NOBR></SPAN> <SPAN 
class=ps12><NOBR>图<SPAN class=em1>1-9</SPAN>中是一个扩展的区域，以及与<SPAN 
class=em1>PSTN</SPAN>相连的网关。当这样的拓扑存在时，发送呼叫</NOBR></SPAN> <SPAN 
class=ps13><NOBR>的最可能方案是通过<SPAN class=em1>GK</SPAN>为呼叫方发送信令，用<SPAN 
class=em1>GW</SPAN>为<SPAN class=em1>GK</SPAN>处理呼叫。在这种情况下，<SPAN 
class=em1>GW</SPAN>经常</NOBR></SPAN> <SPAN 
class=ps14><NOBR>作为端点使用，呼叫模型包括多个独立建立和中止的呼分段。在拨打的电话号码的数字分析</NOBR></SPAN> <SPAN 
class=ps15><NOBR>的基础上选择<SPAN class=em1>TDM</SPAN>干线时，极有可能由<SPAN 
class=em1>GW</SPAN>向<SPAN class=em1>PSTN</SPAN>使用<SPAN 
class=em1>SS7</SPAN>信令，为拨打的特殊数字设置其</NOBR></SPAN> <SPAN 
class=ps16><NOBR>他形式的信令，这些都是应该考虑的问题，为紧急情况<SPAN class=em1>911</SPAN>呼叫、<SPAN 
class=em1>411</SPAN>和<SPAN class=em1>x11</SPAN>呼叫路由、拨打</NOBR></SPAN> <SPAN 
class=ps17><NOBR><SPAN class=ft1>800<SPAN class=em0>数字等的</SPAN>MF<SPAN 
class=em0>信令等。总而言之，现在的</SPAN>PSTN<SPAN class=em0>提供多种服务，在</SPAN>H.323<SPAN 
class=em0>中为提供</SPAN>PSTN<SPAN class=em0>接入</SPAN></SPAN></NOBR></SPAN> <SPAN 
class=ps18><NOBR>必须使用<SPAN class=em1>GW</SPAN>。这为选择端点到<SPAN 
class=em1>GK</SPAN>直接呼叫信令路由造成了困难，除非把<SPAN class=em1>GK</SPAN>和<SPAN 
class=em1>GW</SPAN>集成到一</NOBR></SPAN> <SPAN 
class=ps19><NOBR>起。其中最重要的特性之一就是操作员服务，而这在企业网中通常是不存在的。</NOBR></SPAN> <SPAN 
class=ps20><NOBR>我们已经简单地讨论了<SPAN class=em1>MCU<SPAN 
class=em0>，</SPAN></SPAN>后面在一个呼叫模型的场景中，将看到它的使用。<SPAN 
class=em1>ITU</SPAN>把</NOBR></SPAN> <SPAN class=ps21><NOBR><SPAN 
class=ft1>MCU<SPAN 
class=em0>宽松地定义为网桥，它的作用和通常用于远程会话的桥十分相似。它是网络中的一个端</SPAN></SPAN></NOBR></SPAN> 
<SPAN class=ps22><NOBR>点，允许呼叫的各方参与会话。使用<SPAN 
class=em1>MCU</SPAN>的呼叫不必以会话开始，但随着其他方的加入，它</NOBR></SPAN> <SPAN 
class=ps23><NOBR>可以发展成为会话。<SPAN 
class=em1>MCU</SPAN>至少包含一个音频处理器，为音频流提供混合和交换。<SPAN 
class=em1>MCU</SPAN>包括一</NOBR></SPAN> <SPAN class=ps24><NOBR>个多点控制器（<SPAN 
class=em1>Multipoint Controller</SPAN>，<SPAN class=em1>MC</SPAN>）和一个多点处理器（<SPAN 
class=em1>Multipoint Processor</SPAN>，<SPAN class=em1>MP</SPAN>）。</NOBR></SPAN> 
<SPAN class=ps25><NOBR><SPAN class=ft1>MC<SPAN 
class=em0>处理呼叫控制信令，而</SPAN>MP<SPAN 
class=em0>提供混合、交换和可能的介质转换，从而可以容纳各用户。在不</SPAN></SPAN></NOBR></SPAN> <SPAN 
class=ps26><NOBR>同的拓扑结构中，<SPAN class=em1>MC</SPAN>和<SPAN 
class=em1>MP</SPAN>的实际实现和<SPAN 
class=em1>MCU</SPAN>的位置有所不同，这时不再受协议标准的支配。</NOBR></SPAN> <SPAN 
class=ps27><NOBR><SPAN class=ft1>3. H.323<SPAN 
class=em4>协议</SPAN></SPAN></NOBR></SPAN> <SPAN class=ps28><NOBR>图<SPAN 
class=em1>1-11</SPAN>是<SPAN class=em1>H.323</SPAN>音频、视频和传真应用标准的范围。除了<SPAN 
class=em1>H.225.0</SPAN>用于呼叫信令，<SPAN class=em1>RAS</SPAN>、</NOBR></SPAN> <SPAN 
class=ps29><NOBR><SPAN class=ft1>H.245<SPAN class=em0>用于介质控制以外，<SPAN 
class=em1>H.323</SPAN>标准还规定了</SPAN>RTP<SPAN class=em0>作为介质传输协议。</SPAN>RTCP<SPAN 
class=em0>是</SPAN>RTP<SPAN class=em0>的伴随控</SPAN></SPAN></NOBR></SPAN> <SPAN 
class=ps30><NOBR><SPAN class=ft3>24&nbsp;&nbsp;<SPAN class=em2>IP </SPAN><SPAN 
class=em5>电话技术：稳定的</SPAN><SPAN class=em2>VoIP</SPAN><SPAN 
class=em5>服务集成</SPAN></SPAN></NOBR></SPAN> <SPAN class=ps31><NOBR><SPAN 
class=ft4>文档</SPAN></NOBR></SPAN> <SPAN class=ps32><NOBR><SPAN 
class=ft5>H.225.0</SPAN></NOBR></SPAN> <SPAN class=ps33><NOBR><SPAN 
class=ft6>呼叫信令信道路由</SPAN></NOBR></SPAN> <SPAN class=ps34><NOBR><SPAN 
class=ft6>关守路由</SPAN></NOBR></SPAN> <SPAN class=ps35><NOBR><SPAN 
class=ft6>关守路由</SPAN></NOBR></SPAN> <SPAN class=ps36><NOBR><SPAN 
class=ft6>直接</SPAN></NOBR></SPAN> <SPAN class=ps37><NOBR><SPAN 
class=ft5>H.245</SPAN></NOBR></SPAN> <SPAN class=ps38><NOBR><SPAN 
class=ft6>直接路由</SPAN></NOBR></SPAN> <SPAN class=ps39><NOBR><SPAN 
class=ft5>H.245</SPAN></NOBR></SPAN> <SPAN class=ps40><NOBR><SPAN 
class=ft6>直接路由</SPAN></NOBR></SPAN> </BODY></HTML>
⌨️ 快捷键说明

复制代码 Ctrl + C
搜索代码 Ctrl + F
全屏模式 F11
切换主题 Ctrl + Shift + D
显示快捷键 ?
增大字号 Ctrl + =
减小字号 Ctrl + -