Cisco路由器可以在整塊或重疊模式下接收ISDN呼叫。當配置為整塊時,設定消息應包含路由呼叫所需的所有必要編址資訊。在重疊中,設定消息不包含完整的地址。需要主叫方發出其他資訊消息才能完成被叫地址。
在重疊模式下配置Cisco路由器接收ISDN呼叫時,撥號對等體的配置不正確是一個常見缺陷。這可能會導致錯誤接收被叫號碼,從而導致呼叫失敗。
如需文件慣例的詳細資訊,請參閱思科技術提示慣例。
本文檔的讀者應瞭解:
在思科路由器上配置ISDN
撥號對等體和IP語音(VoIP)基礎知識
本文中的資訊係根據以下軟體和硬體版本:
Cisco IOS®軟體版本12.2.(7)a
C3640路由器
本文中的資訊是根據特定實驗室環境內的裝置所建立。文中使用到的所有裝置皆從已清除(預設)的組態來啟動。如果您在即時網路中工作,請確保在使用任何命令之前瞭解其潛在影響。
在D通道上配置重疊接收改變了路由器接收ISDN呼叫時的行為。路由器使用SETUP ACK響應設定消息。這通知網路它準備接收包含附加呼叫路由元素的進一步資訊消息。
當撥號對等體中使用的目標號碼與接收的被叫號碼的長度不同時,會發生此問題。如下圖所示,目標號碼彙總以反映可能以相同數字開頭的一系列號碼:
目的地號碼範圍為5000到5600。
撥號對等體可配置為目標模式5。
這種撥號方案在En bloc模式下工作正常,但在Overlap接收路由器時,它會嘗試在收到與目標號碼匹配的足夠數字後發出呼叫。在本例中,在收到5之後。為防止出現這種情況,應將終止符「T」置於目標模式中的數字之後。這會導致路由器等待T302計時器在接收每個數字後過期,從而允許在進行呼叫之前收集全號碼。
以下是導致呼叫失敗的組態範例:
! interface Serial3/0:15 no ip address no logging event link-status isdn switch-type primary-qsig isdn overlap-receiving isdn incoming-voice voice isdn send-alerting no cdp enable ! ! voice-port 3/0:15 ! dial-peer cor custom ! ! dial-peer voice 1 voip destination-pattern 5 session target ipv4:10.0.0.1 ! !
debug ISDN Q931和debug voip ccapi inout命令已啟用。為清楚起見,部分調試被省略。
ECV-3640-2# *Mar 2 01:47:05.705: ISDN Se3/0:15: RX <- SETUP pd = 8 callref = 0x001A *Mar 2 01:47:05.705: Bearer Capability i = 0x8090A3 *Mar 2 01:47:05.709: Channel ID i = 0xA9839B *Mar 2 01:47:05.709: Facility i = 0x91AA068001008201008B0102A11 402025CA002013B300B30090A01050A01030A0104 *Mar 2 01:47:05.713: Facility i = 0x91AA068001008201008B0100A10 C02025CB006042B0C09008400 *Mar 2 01:47:05.713: Calling Party Number i = 0x00, 0x83, '5000', Plan:Unknown, Type:Unknown *Mar 2 01:47:05.717: Called Party Number i = 0x80, '5', Plan:Unknown, Type:Unknown *Mar 2 01:47:05.717: High Layer Compat i = 0x9181 !--- An incoming call with the first digit of called number 5. *Mar 2 01:47:05.729: ISDN Se3/0:15: TX -> SETUP_ACK pd = 8 callref = 0x801A *Mar 2 01:47:05.729: Channel ID i = 0xA9839B *Mar 2 01:47:06.385: ISDN Se3/0:15: RX <- INFORMATION pd = 8 callref = 0x001A *Mar 2 01:47:06.385: Called Party Number i = 0x80, '5', Plan:Unknown, Type:Unknown !--- An information message with the next digit 5. *Mar 2 01:47:06.393: ccCallSetupRequest numbering_type 0x80 *Mar 2 01:47:06.393: ccCallSetupRequest encapType 2 clid_restrict_disable 1 null_orig_clg 0 clid_transparent 0 callingNumber 5000 *Mar 2 01:47:06.393: dest pattern 5, called 55, digit_strip 0 *Mar 2 01:47:06.393: callingNumber=5000, calledNumber=55, redirectNumber= display_info= calling_oct3a=83 !--- The router matches received digits 55 with dial peer 1. *Mar 2 01:47:06.421: ccCallDisconnect (callID=0x25, cause=0x1 tag=0x0) *Mar 2 01:47:06.421: ccCallDisconnect (callID=0x24, cause=0x1 tag=0x0) *Mar 2 01:47:06.425: cc_api_call_disconnect_done(vdbPtr=0x62679168, callID=0x24, disp=0, tag=0x0) !--- The call was disconnected from the remote router, because !--- the number is incomplete as only 55 is sent, this fails to match any dial !--- peers (dial peers at remote router were four digits in length). *Mar 2 01:47:06.433: ISDN Se3/0:15: TX -> DISCONNECT pd = 8 callref = 0x801A *Mar 2 01:47:06.433: Cause i = 0x8081 - Unallocated/unassigned number !--- The call was disconnected because of an unallocated/unassigned number. ECV-3640-2# ECV-3640-2# ECV-3640-2# ECV-3640-2#
在本例中,撥出的號碼是5678。現在通過新增「T」終結器糾正了撥號對等體。重疊配置還包括調整T302計時器以反映更真實的配置。預設計時器為10秒,在某些情況下可能太長。
interface Serial3/0:15 no ip address no logging event link-status isdn switch-type primary-qsig isdn overlap-receiving T302 2000 !--- The T302 timer is configured to wait for two seconds. isdn incoming-voice voice isdn send-alerting no cdp enable ! ! voice-port 3/0:15 ! dial-peer cor custom ! ! ! dial-peer voice 1 voip destination-pattern 5T !--- The "T" is added to the dial peer. session target ipv4:10.0.0.1 ! end ECV-3640-2# *Mar 2 21:36:10.132: ISDN Se3/0:15: RX <- SETUP pd = 8 callref = 0x0024 *Mar 2 21:36:10.136: Bearer Capability i = 0x8090A3 *Mar 2 21:36:10.136: Channel ID i = 0xA98386 *Mar 2 21:36:10.136: Facility i = 0x91AA068001008201008B0102A114020262A 002013B300B30090A01050A01030A0104 *Mar 2 21:36:10.140: Facility i = 0x91AA068001008201008B0100A10C020262B 006042B0C09008400 *Mar 2 21:36:10.140: Calling Party Number i = 0x00, 0x83, '5000', Plan:Unknown, Type:Unknown *Mar 2 21:36:10.144: Called Party Number i = 0x80, '5', Plan:Unknown, Type:Unknown *Mar 2 21:36:10.144: High Layer Compat i = 0x9181 !--- An incoming call with the first digit of called number 5. *Mar 2 21:36:10.164: ISDN Se3/0:15: TX -> SETUP_ACK pd = 8 callref = 0x8024 *Mar 2 21:36:10.164: Channel ID i = 0xA98386 *Mar 2 21:36:10.360: ISDN Se3/0:15: RX <- INFORMATION pd = 8 callref = 0x0024 *Mar 2 21:36:10.364: Called Party Number i = 0x80, '6', Plan:Unknown, Type:Unknown !--- An information message with the next digit 6. *Mar 2 21:36:10.660: ISDN Se3/0:15: RX <- INFORMATION pd = 8 callref = 0x0024 *Mar 2 21:36:10.664: Called Party Number i = 0x80, '7', Plan:Unknown, Type:Unknown !--- An information message with the next digit 7. *Mar 2 21:36:10.924: ISDN Se3/0:15: RX <- INFORMATION pd = 8 callref = 0x0024 *Mar 2 21:36:10.924: Called Party Number i = 0x80, '8', Plan:Unknown, Type:Unknown !--- An information message with the next digit 8. *Mar 2 21:36:20.168: ccCallSetupRequest encapType 2 clid_restrict_disable 1 null_orig_clg 0 clid_transparent 0 callingNumber 5000 *Mar 2 21:36:20.172: dest pattern 5T, called 5678, digit_strip 0 *Mar 2 21:36:20.172: callingNumber=5000, calledNumber=5678, redirectNumber= display_info= calling_oct3a=83 !--- The router matches received digits 5678 with dial peer 1. *Mar 2 21:36:20.228: ISDN Se3/0:15: TX -> CALL_PROC pd = 8 callref = 0x8024 *Mar 2 21:36:20.420: cc_api_call_cut_progress(vdbPtr=0x6221F1E8, callID=0x38, prog_ind=0x8, sig_ind=0x1) *Mar 2 21:36:20.440: ISDN Se3/0:15: TX -> ALERTING pd = 8 callref = 0x8024 *Mar 2 21:36:20.440: Progress Ind i = 0x8188 - In-band info or appropriate now available !--- The call is successfully routed and the remote phone is ringing. ECV-3640-2#