语音 : H.323

针对点号和星号的区域前缀处理

2015 年 8 月 28 日 - 机器翻译
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目录


简介

本文讨论一些网络实施遇到了与使用小点作为在区域前缀内的通配符的问题。它然后提交一个方案对此问题通过报价使用,哪里可能,星号(*)通配符。最后,本文澄清与一个特定参考的区域处理逻辑对配置之间通配符两个方法的差异。

先决条件

要求

本文读者应该对H.323流和Cisco网守概念熟悉,特别是区域处理。参考了解Cisco IOS网守呼叫路由配置H.323网守和代理关于Cisco网守和区域处理的更多信息。第一这些文档为了解网守区域处理是有用的。

使用的组件

本文档不限于特定的软件和硬件版本。

规则

有关文档规则的详细信息,请参阅 Cisco 技术提示规则

问题

与使用涉及的混乱的根本原因小点和星号在网守的默认行为在,当处理前缀时。此行为,详细描述在本文的网守默认区域前缀处理行为部分的说明,能创建模棱两可的情况,如果有在拨号计划的一重叠,并且配置利用小点和星号。

问题的症状和特性是:

  • 本地关守预计路由呼叫到超过一个本地区域或预计路由呼叫到在远程区域或两个的网守。

  • 在本地区域内的呼叫可以顺利地路由。

  • 一些,但是不是所有,地区之间呼叫可以顺利地路由。

  • 没有顺利地路由的地区之间呼叫是到被叫号码用位一个特定编号。例如,而对开始与同一个位的三位数的一呼叫可靠发生故障,对10位或九字节编号的呼叫可能成功。

  • 网守配置利用在区域前缀内的小点通配符。

解决方案

当您指定在区域前缀内时的通配符位,尽可能请避免使用小点。反而,请使用不太具体的星号通配符。当您遵守这些规则时,您能也避免问题:

  1. 如果拨号计划一致,您能以仅小点(或使用仅星号)使用配置。

  2. 如果有在拨号计划的一重叠,坚持使用配置以星号是最佳的。

  3. 如果有在拨号计划的重叠,并且与仅星号的一配置不是适当的,请学习前缀猜测网守的默认行为(请推导并且加在前面本地区号),在您配置网守前。

第三个规则要求对网守的行为的详细信息的了解正如本文所描述。

网守默认区域前缀处理行为的解释

以从H.323终端时的一Admission Request (ARQ)的形式,当处理呼叫请求此示例说明网守的行为。步骤2和3为范围是关键本文。您能通过此流程图跨步后在本文对示例调试的关于:一失败呼叫

/image/gif/paws/23900/zone_pre_process_dots_asterisks-1.gif

区域前缀处理跟目的地前缀处理有些不同。当您匹配区域前缀时,若可能Cisco网守做一特殊尝试由区域代码合格区域。如果被叫号码在本地区域匹配,网守推导应该加在前面本地区号(呼叫号码的前缀)到被叫号码。

例如, ARQ进入一网守用呼叫号码"415xxxxxxx" (与区域代码415)。

网守有作为支持的前缀配置的415区域"415......." (七个小点)。因此条目,如果被叫号码是5551212 (特别地七个位)然后网守加在前面它与前缀和呼叫号码一样。所以,将处理的被叫号码是4155551212,在本地区域。

注意: 小点数量在zone prefix命令的确定被叫号码是否在本地区域配比。在上面一个六字节编号(例如:555123)不配比与已配置的区域前缀"415......." (七个小点)。所以,被叫号码没有推导是415555123,然而保持555123并且匹配区域前缀"555*"。

然而,如果本地区域配置作为"415*"和配置也包括处理“*”,然后,当询问解决地址5551212,网关进程ARQ如匹配在区域x的默认区域x,如果X是本地关守的另一个区域,或者发送位置请求(LRQ)对X,如果它是远程区域。

这是说明概念对匹配Cisco IOS 配置片断的关于的示例。

与小点的区域前缀行为与星号–网守配置片断

!--- 5551212 is the called number 
!--- and the request comes into zone localzone2.
!--- It is important to know that the calling number has prefix 415.  

zone prefix localzone2 415.......
zone prefix localzone1 555*

!--- In this case, this line is what the match is with.

Zone prefix localzone2 415.......

!--- The match is due to these reasons:


!--- 1. The calling number begins with 415.
!--- 2. There is a local wildcard entry for 415 with seven dots. This entry
!--- causes the gatekeeper to assume that the the seven-digit called
!--- number is local and therefore expands 5551212 to 4155551212 by 
!--- prepending the area code of the calling number. This expanded
!--- number matches, and the call will be accepted or rejected based on
!--- the registered resources, in localzone2.


!--- If the configuration is changed, as shown here, then there is no
!--- expansion of the number (because there is no seven-dot entry). 

zone prefix localzone2 415*
zone prefix localzone1 555*

!---  This line is what the match is now with.

Zone prefix localzone1 555* 

!--- In this case, the call is accepted or rejected based on registered
!--- resources in localzone1.

案例研究

注意: 此案例研究利用有两个本地区域的单个关守。同样原理适用对本地关守配置转发LRQs到远程区域网守的多种关守设计。

此图表显示“新建的世界”服务提供商网络的一个简化H.323区域视图。此网络在呼叫localzone2的区域提供在H.323客户端之间的VoIP呼叫,并且存取对于从那些同样客户端的公共交换电话网(PSTN)。提供存取对于PSTN的中继网关(TGWs)位于呼叫localzone1的一个分开的区域。

zone_pre_process_dots_asterisks-2.gif

注意: H.323客户端可以是本地H.323 IP电话用户,简单analogue-to-H.323适配器设备,例如Cisco ATA或其他相似的第三方产品或者较大规模的网关。较大规模的网关设计的支持,特殊那些与远程电话用户,可能将需要一个更加复杂的区域结构比什么在这种情况下讨论学习。另外, 5350个TGWs能通过数字E1/T1连接提供PSTN访问例如主速率ISDN或随路信令(CAS)。他们能也提供直接SS7互连使用一适当的SS7呼叫代理,例如思科SC2000或PGW2200。

configuration 和 show 命令

在网守安装的关守相关的命令显示此处。突出显示的线路在配置里是重大的在以后展示与,在这种情况下的问题,呼叫从localzone2尝试到localzone1的三字节电话号码。

网守配置(仅网守命令)
gatekeeper
  zone local localzone1 dns.au 10.1.1.228
  zone local localzone2 dns.au
  no zone subnet localzone1 default enable
  zone subnet localzone1 10.1.1.240/28 enable
  no zone subnet localzone2 default enable
  zone subnet localzone2 10.99.0.0/16 enable
  zone prefix localzone1 0*
  zone prefix localzone1 1*
  zone prefix localzone1 6*
  zone prefix localzone1 8*
  zone prefix localzone2 9999931..
  Zone prefix localzone2 9999932..
  Zone prefix localzone2 9999933..
  Zone prefix localzone2 9999934..
  Zone prefix localzone2 9999935..
  Zone prefix localzone2 9999936..
  Zone prefix localzone2 9999937..
  Zone prefix localzone2 9999938..
  Zone prefix localzone2 9999939..
  Zone prefix localzone2 999994...
  zone prefix localzone2 999995...
  zone prefix localzone1 9*
  accounting vsa
  gw-type-prefix 1#* default-technology
  arq reject-unknown-prefix
  lrq reject-unknown-prefix
  no use-proxy localzone2 default inbound-to terminal
  no use-proxy localzone2 default outbound-from terminal
  no shutdown
  endpoint ttl 60

show gatekeeper endpoints命令输出显示用网守注册的H.323终端与他们注册的区域一起。

注意: 当H.323终端在localzone2时,注册TGWs正确地注册到在localzone1的网守。

show gatekeeper endpoints
GK#show gatekeeper endpoints 
GATEKEEPER ENDPOINT REGISTRATION
================================
CallSignalAddr  Port  RASSignalAddr   Port  Zone Name     Type Flags
--------------- ----- --------------- ----- ---------     ---- -----
10.99.0.10      1720  10.99.0.10      45690 localzone2    TERM E164-ID: 999995988
10.99.0.11      1720  10.99.0.11      29249 localzone2    TERM E164-ID: 999995981
10.99.0.12      1720  10.99.0.12      19227 localzone2    TERM E164-ID: 999995985
10.99.0.15      1720  10.99.0.15      36889 localzone2    TERM E164-ID: 999995989
10.99.0.16      1720  10.99.0.16      42366 localzone2    TERM E164-ID: 999995982
10.99.0.18      1720  10.99.0.18      18300 localzone2    TERM E164-ID: 999995986
10.99.0.19      1720  10.99.0.19      32345 localzone2    TERM E164-ID: 999995980
10.99.0.20      1720  10.99.0.20      23155 localzone2    TERM E164-ID: 999995984
10.1.1.240      1720  10.1.1.240      50737 localzone1    VOIP-GW H323-ID: tgw1@dns.au
10.1.1.241      1720  10.1.1.241      50737 localzone1    VOIP-GW H323-ID: tgw2@dna.au
Total number of active registrations = 10

show gatekeeper zone prefix命令输出正确地指示各自E.164前缀将路由的区域。

show gatekeeper zone prefix
ZRZ-GK1#show gatekeeper zone prefix
	    ZONE PREFIX TABLE
            =================
GK-NAME               E164-PREFIX
-------               -----------
localzone1            0*
localzone1            1*
localzone1            6*
localzone1            8*
localzone2            9999931..
localzone2            9999932..
localzone2            9999933..
localzone2            9999934..
localzone2            9999935..
localzone2            9999936..
localzone2            9999937..
localzone2            9999938..
localzone2            9999939..
localzone2            999994...
localzone2            999995...
localzone1            9*

show gatekeeper gw-type-prefix命令输出显示为此网守配置的技术前缀。

注意仅默认tech-前缀(1#)在网守配置。另外,仅5350个TGWs (tg1和tgw2)在区域localzone1配置向此默认技术前缀登记。

show gatekeeper gw-type-prefix
GK#show gatekeeper gw-type-prefix 
GATEWAY TYPE PREFIX TABLE
=========================
Prefix: 1#*    (Default gateway-technology)
  Zone localzone1 master gateway list:
    10.1.1.240:1720 tgw1 
    10.1.1.241:1720 tgw2 (out-of-resources)

调试和详细讨论

这是从显示注册、准入和状态协议的网守的debug输出(RAS)流和区域前缀处理:

它包括解释网守行为,当处理在区域前缀的小点通配符与星号通配符比较时的一个详细的评论。

debug h225 asn1和debug gatekeeper main 10 –失败呼叫
GK#show debug
gk main debug level = 10
H.225: H.225 ASN1 Messages debugging is on

!--- This output is from the debug h225 ans1 command issued on the gatekeeper. It shows 
!--- an incoming RAS ARQ for called number 112. It is important to
!--- note that the calling number (source endpoint) comes from the zone localzone2 and,
!--- assuming three-digit numbers, its prefix (source endpoint prefix) is 999995.
  
Mar 11 21:48:15: RAS INCOMING PDU ::=

value RasMessage ::= admissionRequest : 
    {
      requestSeqNum 36784
      callType pointToPoint : NULL
      callModel gatekeeperRouted : NULL
      endpointIdentifier {"618FED9800000008"}
      destinationInfo 
      {
        e164 : "112",
        e164 : "112"
      }
      srcInfo 
      {
        h323-ID : {"999995985"},
        e164 : "999995985"
      }
      srcCallSignalAddress ipAddress : 
      {
        ip '0A14000C'H
        port 11309
      }
      bandWidth 1280
      callReferenceValue 31633
      conferenceID '5634343434EF21002B211E5226E91D26'H
      activeMC FALSE
      answerCall FALSE
      canMapAlias FALSE
      callIdentifier 
      {
        guid '5634343434EF20002B211E5226E91D26'H
      }
      gatekeeperIdentifier {"localzone2"}
      willSupplyUUIEs FALSE
    }

!--- This output is from the debug gatekeeper main 10 command 
!--- issued on the gatekeeper. It 
!--- shows the gatekeeper zone prefix processing logic (rassrv_get_addrinfo). 
!--- Comments are inserted throughout. 

Mar 11 21:48:15: gk_rassrv_arq: arqp=0x61A09EE4, crv=0x7B91, answerCall=0
Mar 11 21:48:15: ARQ Didn't use GK_AAA_PROC

!--- Tech-prefix matching occurs first. In this case study, no
!--- tech-prefixes are configured so no match is found. 

Mar 11 21:48:15: rassrv_get_addrinfo(112): Tech-prefix match failed.

!--- The next line in the trace is the key to what, in this case study, is unexpected 
!--- behavior. The expected behavior is for 112 to match with the wildcard "1*" entry 
!--- in localzone1. 

!--- The local (source) zone of the calling number is localzone2. 
!--- It has been configured as 
!--- supporting the prefix "999995..." with three wildcard digits. 
!--- (Note the configuration line 
!--- "zone prefix localzone2 999995...".)

!--- The gatekeeper, when asked to resolve a three-digit number 112, 
!--- deduces this to mean "999995-112" in the local zone because 
!--- "112" matches with the specific-length three-dot 
!--- wildcard configuration for the local zone. 

!--- This behavior is exactly the same as a local area code being assumed when a local 
!--- call is made. 



!--- If the configuration line "zone prefix localzone2 999995..." was removed from the 
!--- configuration, or if the line "zone prefix localzone2 999995*" was inserted instead,
!--- then the three-digit number "112" would not match in the local 
!--- zone but would rather match localzone1 through the 
!--- configuration line "zone prefix localzone1 1*".

Mar 11 21:48:15: rassrv_get_addrinfo(112): Defaulting to source endpoint's zone prefix 999995

Mar 11 21:48:15: No tech-prefix

Mar 11 21:48:15: Alias not found

!--- The gatekeeper attempts to find a default technology prefix, But although "#1" is 
!--- configured, the H.323 endpoints in localzone2 correctly do not register with that. The
!--- conclusion drawn is that there is an "unknown address and no default 
!--- technology defined":

Mar 11 21:48:15: rassrv_get_addrinfo(112): default-tech gateway selection failed, status = 0x805
Mar 11 21:48:15: rassrv_get_addrinfo(112): unknown address and no default technology defined.
Mar 11 21:48:15: rassrv_get_addrinfo(112): Tech-prefix match failed.
Mar 11 21:48:15: rassrv_get_addrinfo(112): Defaulting to source endpoint's zone prefix 999995
Mar 11 21:48:15: No tech prefix

Mar 11 21:48:15: Alias not found

!--- The gatekeeper indicates that it has failed to find a registered match for the  
!--- called number in localzone2:

Mar 11 21:48:15: rassrv_get_addrinfo(112): default-tech gateway selection failed, status = 0x805
Mar 11 21:48:15: rassrv_get_addrinfo(112): unknown address and no default technology defined.
Mar 11 21:48:15: gk_rassrv_sep_arq(): rassrv_get_addrinfo() failed (return code = 0x103)

!--- The gatekeeper sends the Admission Reject (ARJ) because the called party is not 
!--- registered:

Mar 11 21:48:15: RAS OUTGOING PDU ::=

value RasMessage ::= admissionReject : 
    {
      requestSeqNum 36784
      rejectReason calledPartyNotRegistered : NULL
    }

此调试是从输出的解压缩debug gatekeeper main 10命令并且显示成功的呼叫。

debug gatekeeper main 10 –成功的呼叫
GK#show debug
gk main debug level = 10
H.225: H.225 ASN1 Messages debugging is on

!--- The four-digit called number 1003 does not match with the three-dot wildcard 
!--- for localzone2 noted earlier. Instead, it matches with the less-specific 
!--- asterisk wildcard for localzone1.

Feb 19 16:52:19: rassrv_get_addrinfo(1003): Tech-prefix match failed.
Feb 19 16:52:19: rassrv_get_addrinfo(1003): Matched zone prefix 1 and remainder 003
Feb 19 16:52:19: No tech prefix
Feb 19 16:52:19: Alias not found

!--- The gatekeeper finds a default technology prefix (of #1) since the 5350
!--- TGWs register with this prefix as per the 
show gatekeeper gw-type-prefix
 command.

Feb 19 16:52:19: Technology GW selected

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Document ID: 23900