Troubleshooting Network Infrastructure © 2004 Cisco Systems, Inc. All rights reserved. IPTT v Troubleshooting Cisco Gateways

© 2004 Cisco Systems, Inc. All rights reserved. IPTT v Upon completing this lesson, you will be able to: Identify common voice issues related to Gateway configurations Identify common issues with digital voice interfaces Identify common IOS Configuration issues for H.323, MGCP, SIP Describe the operation of Call Flow in Cisco IOS gateway Explain the operation and configuration of SRST in the branch office Troubleshooting Gateways: Objectives

© 2004 Cisco Systems, Inc. All rights reserved. IPTT v Outline Overview Troubleshooting Common Gateway Issues Troubleshooting Common Digital Voice Connections Signaling Protocol Configuration Dial Peers and Digit Analysis Router Call Flow and Call Control Survival Remote Site Telephony Summary Quiz

© 2004 Cisco Systems, Inc. All rights reserved. IPTT v The gateway is the interface between the data network, IP WAN, and the PSTN. Troubleshooting Common Gateway Issues Applications (VMail, IVR, ICD,...) Headquarters Branch A Branch B Cisco CallManager Cluster SRST-Enabled Router SRST-Enabled Router Gatekeeper PSTN IP WAN

© 2004 Cisco Systems, Inc. All rights reserved. IPTT v Analog T1/ISDN PRI T1/CAS Cisco CallManager PSTN H.225 PSTNIP Analog T1/ISDN PRI T1/CAS Cisco CallManager PSTN MGCP H.323 MGCP Backhauling All PSTN signaling terminates on gateway. H.225 communication between gateway and Cisco CallManager. H.323 is a peer-to-peer protocol. Framing and Layer 2 signaling terminates at the gateway. Layer 3 signaling is backhauled to Cisco CallManager. MGCP is a client-server protocol. PRI Layer Troubleshooting Common Gateway Issues (Cont.)

© 2004 Cisco Systems, Inc. All rights reserved. IPTT v When a setup message arrives to the originating gateway with PI=3, this message indicates to the gateway that in-band messages are available. Progress indicates of tones and announcements are available is signaled by an alerting, call proceeding, progress, connect, setup acknowledgment, or disconnect message contained in a PI of 1 or 8. Troubleshooting Common Gateway Issues (Cont.)

© 2004 Cisco Systems, Inc. All rights reserved. IPTT v H.323 Gateway Cisco CallManager In-band ringing Alerting PI=0 No ringback on an IP Phone when calling the PSTN Call Direction Troubleshooting Common Gateway Issues: (H.323) PSTN

© 2004 Cisco Systems, Inc. All rights reserved. IPTT v Setup PI=0 No ringback on a PSTN phone when calling an IP Phone H.225 Alerting No ringback! Troubleshooting Common Gateway Issues: (H.323) (Cont.) H.323 Gateway In-band ringing Call Direction PSTN Cisco CallManager

© 2004 Cisco Systems, Inc. All rights reserved. IPTT v H.323 Gateway Ringback! No ringback to PSTN when IP Phones initiate a call transfer H.225 User InfoProgress Transfer Troubleshooting Common Gateway Issues: (H.323) (Cont.) PSTN No ringback Cisco CallManager

© 2004 Cisco Systems, Inc. All rights reserved. IPTT v PSTN H.323 Gateway Disconnect pd=8 An IP Phone user does not hear a busy signal when calling a busy number on the PSTN; instead, the call is disconnected. No busy tone or PSTN message is heard Call Direction Troubleshooting Common Gateway Issues: (H.323) (Cont.) Cisco CallManager

© 2004 Cisco Systems, Inc. All rights reserved. IPTT v H.323 Gateway One-way or no-way audio Troubleshooting Common Gateway Issues: (H.323) (Cont.) PSTN IP WAN Cisco CallManager

© 2004 Cisco Systems, Inc. All rights reserved. IPTT v H.323 Gateway No DTMF digits or audio passed on calls to PSTN/PBX PSTN/PBX Call Direction Troubleshooting Common Gateway Issues: (H.323) (Cont.) Cisco CallManager

© 2004 Cisco Systems, Inc. All rights reserved. IPTT v PSTN IP WAN MGCP Gateway FXS/FXO ISDN-PRI/CAS The gateway or endpoints or both do not get registered with CallManager. Troubleshooting Common Gateway Issues: (MGCP) Cisco CallManager

© 2004 Cisco Systems, Inc. All rights reserved. IPTT v Total number of host: 2 Priority Status Host ========================================= Primary Registered First backup Backup ready Current active Call Manager: Current backup Call Manager: Redundant link port: 2428 Failover Interval: 30 seconds Keepalive Interval: 15 seconds Last keepalive check: 00:00:00 Last MGCP traffic time: 00:00:32 Last switchover time: None Switchback mode: Immediate Troubleshooting Common Gateway Issues: (MGCP) (Cont.)

© 2004 Cisco Systems, Inc. All rights reserved. IPTT v Troubleshooting dropped calls when a PSTN call has been established: –Dropped calls can be the result of a flapping circuit, phone, or gateway resetting. Use debug commands. Check the Microsoft Windows 2000 Event Viewer in Cisco CallManager, look for cause codes, and cross reference the cause codes to system errors messages Troubleshooting Common Gateway Issues: (Dropped Calls)

© 2004 Cisco Systems, Inc. All rights reserved. IPTT v Is reorder tone (fast busy) heard during digit entry or after all digits are entered? Gateway Cisco CallManager during after H.323/MGCP/SIP Troubleshooting Common Gateways Issues: (Reorder Tone) PSTN IP WAN

© 2004 Cisco Systems, Inc. All rights reserved. IPTT v Troubleshooting Common WS-X6624 and WS-X6608-T1/E1 Issues Layer 3 connectivity to Cisco CallManager Port registration problem represents one of the most common issues MAC address of the port is incorrect in Cisco CallManager DHCP is not enabled or disabled Missing or corrupt Device Default application load

© 2004 Cisco Systems, Inc. All rights reserved. IPTT v Troubleshooting Common Digital Gateway Issues Troubleshooting digital interfaces Start with Layer 1, then work up –show controllers [t1 | e1] (shows error) –show isdn status (Layers 2 and 3 status) –debug q921/q931 (Layers 2 and 3 activity) –debug vpm signal

© 2004 Cisco Systems, Inc. All rights reserved. IPTT v Troubleshooting Common Digital Gateway Issues (Cont.) T1/ISDN PRI –show controller [t1 | e1] (Layer 1) –show isdn status –debug q921 (Layer 2) –debug q931 (Layer 3) T1/CAS –show controller (Layer 1) –show voice all summary –debug vpm signal

© 2004 Cisco Systems, Inc. All rights reserved. IPTT v Signaling Protocol Configuration: H.323 controller T1 2/0 framing esf linecode b8zs pri-group timeslots 1-24 ! Controller T1 2/1 framing esf linecode b8zs ds0-group 0 timeslots 1-24 type e&m-wink-start ! interface Serial2/0:23 no ip address no logging event link-status isdn switch-type primary-ni isdn incoming-voice voice no cdp enable ! interface Serial2/1:23 no ip address no logging event link-status isdn switch-type primary-ni isdn incoming-voice voice no cdp enable voice-port 2/0:23 ! voice-port 2/1:0 ! dial-peer voice 3000 voip destination-pattern 30.. session target ipv4: codec g711ulaw ! dial-peer voice 12 pots destination-pattern 1T direct-inward-dial prefix 1 ! dial-peer voice 22 pots destination-pattern 011T port 2/1:23 prefix 011 A Common H.323 T1/ISDN PRI and CAS Configuration

© 2004 Cisco Systems, Inc. All rights reserved. IPTT v mgcp mgcp call-agent service-type mgcp version 0.1 mgcp dtmf-relay voip codec all mode out-of-band mgcp rtp unreachable timeout 1000 action notify mgcp modem passthrough voip mode cisco mgcp sdp simple mgcp package-capability rtp-package mgcp package-capability sst-package no mgcp timer receive-rtcp no mgcp explicit hookstate ! ccm-manager mgcp ccm-manager config server ccm-manager config ! A Common MGCP T1/ISDN PRI Backhaul Configuration Signaling Protocol Configuration: MGCP

© 2004 Cisco Systems, Inc. All rights reserved. IPTT v ! controller T1 2/0 framing esf clock source internal linecode b8zs cablelength short 133 pri-group timeslots 1-24 service mgcp ! interface Serial2/0:23 no ip address no logging event link-status isdn switch-type primary-ni isdn protocol-emulate network isdn incoming-voice voice isdn T isdn bind-l3 ccm-manager no cdp enable ! voice-port 2/0:23 ! dial-peer cor custom ! dial-peer voice pots application mgcpapp port 2/0:23 Signaling Protocol Configuration: MGCP (Cont.)

© 2004 Cisco Systems, Inc. All rights reserved. IPTT v Gatekeeper Call Admission Control (CAC) Before starting any troubleshooting verify connectivity After verifying connectivity setup traces and run show and debug commands Other than not enough bandwidth, the most common reasons for a call to be rejected: –No zone prefix is configured that matches the dialed digits –No CallManager is registered in the zone where the call is supposed to route to Signaling Protocol Configuration (Gatekeeper)

© 2004 Cisco Systems, Inc. All rights reserved. IPTT v Voice over IP Components SourceDestination R1 R4 Dial-Peer 1 Dial-Peer 3Dial-Peer 2Dial-Peer 4 Call Leg 1 for POTS Dial-Peer 1 Call Leg 2 for VoIP Dial-Peer 2 Call Leg 4 for POTS Dial-Peer 4 Call Leg 3 for VoIP Dial-Peer 3 Four call legs are necessary for an end-to-end telephony conversation, two configured in each router. IP WAN

© 2004 Cisco Systems, Inc. All rights reserved. IPTT v Incoming and Outgoing Dial Peers H.323 Gateway Analog Phone CME/SRST IP Phone PBX 1 2 H.323 Gateway Dial-Peer Matching IP Cisco CallManager IP The reverse is TRUE. POTS VoIP POTS PSTN 3

© 2004 Cisco Systems, Inc. All rights reserved. IPTT v Verifying Dial Peers router# show dial-peer voice summary dial-peer hunt 0 AD PRE PASS TAG TYPE MIN OPER PREFIX DEST-PATTERN FER THRU SESS-TARGET PORT 2222 pots up up / voip up up syst ipv4: router# show dial-peer voice summary dial-peer hunt 0 AD PRE PASS TAG TYPE MIN OPER PREFIX DEST-PATTERN FER THRU SESS-TARGET PORT 2222 pots up up / voip up up syst ipv4:

© 2004 Cisco Systems, Inc. All rights reserved. IPTT v Router Call Flow CLI Telephony SPI VoIP SPI SNMP Session Application Dial Plan Mapper VoFR SPI Call TableInterface Table Dial-Peer Table Call Control API

© 2004 Cisco Systems, Inc. All rights reserved. IPTT v Telephony Interface Architecture Voice Processor Module Voice Telephony Service Provider FXO SSMFXS SSME&M SSM DSP Resource Manager DSP CCAPI Setup/Release Request Setup/Release Ind/Release Application Request Application Response

© 2004 Cisco Systems, Inc. All rights reserved. IPTT v Verifying On-Hook and Off-Hook Signaling debug vpm signal debug vpm spi debug vpm dsp debug vpm all debug vpm port

© 2004 Cisco Systems, Inc. All rights reserved. IPTT v Verifying Digit Collection show dialplan number debug vtsp session debug vtsp dsp

© 2004 Cisco Systems, Inc. All rights reserved. IPTT v Verifying Call Setup and Call Control Phases debug voice ccapi inout debug ip tcp transactions debug ip tcp packet debug h225 events debug h245 events debug cch323 h225 debug cch323 h

© 2004 Cisco Systems, Inc. All rights reserved. IPTT v What Is SRST? Survivable Remote Site Telephony (SRST) Capability in branch office routers for IP telephony redundancy Always available branch IP telephony (including calls to and from PSTN) Ideal for centralized Cisco CallManager deployment Licensed based on number of users at remote site on Cisco IOS software plus Survivability scales up to 480 users dependent upon platform

© 2004 Cisco Systems, Inc. All rights reserved. IPTT v What is SRST? (Cont.) Central Cisco CallManager Cluster Hub Site A Voice Mail V CCM Spoke Site B PSTN CCM primary tertiary secondary IP WAN

© 2004 Cisco Systems, Inc. All rights reserved. IPTT v SRST Version 3.1 Cisco IOS software 12.3(7)T, Cisco CallManager 3.1, 3.2, 3.3, and 4.0(1) SRST Version 3.0 Cisco IOS software 12.3(4)T, 12.2(15)ZJ, Cisco CallManager 3.1, 3.2, 3.3 SRST Version 2.1 Cisco IOS software 12.2(15)T, 12.2(11)YT, Cisco CallManager 3.1, 3.2, 3.3 SRST Version 2.02 Cisco IOS software 12.2(13)T, Cisco CallManager 3.05, 3.1, 3.2 SRST Version 2.01 Cisco IOS software 12.2(11)T, Cisco CallManager 3.05, 3.1, 3.2 SRST Version 2.0 Cisco IOS software 12.2(8)T, 12.2(2)XT, Cisco CallManager 3.05, 3.1, 3.2 Cisco SRST Compatibility

© 2004 Cisco Systems, Inc. All rights reserved. IPTT v Central Site Cisco CallManager Real Time Protocol Headquarters Branch Router 1750, 2600, 3600, 7200, Catalyst 4224 IAD2400 How SRST Works: Normal Operation WAN Skinny: Protocol for call setup and teardown Keepalive: Ensures communication link with Cisco CallManager PSTN

© 2004 Cisco Systems, Inc. All rights reserved. IPTT v Headquarters Real Time Protocol How SRST Works: Network Failure PSTN X WAN Skinny Keepalive (TCP) Keepalive to Cisco CallManager Branch Router 1750, 2600, 3600, 7200, Catalyst 4224 IAD2400 Central Site Cisco CallManager

© 2004 Cisco Systems, Inc. All rights reserved. IPTT v How SRST Works: Network Failure Repaired Real Time Protocol Headquarters Branch Router 1750, 2600, 3600, 7200, Catalyst 4224 IAD2400 WAN PSTN Skinny: Protocol for call setup and teardown Keepalive: Ensures communication link with Cisco CallManager Central Site Cisco CallManager

© 2004 Cisco Systems, Inc. All rights reserved. IPTT v call-manager-fallback SRST(config)# Enables Cisco CallManager fallback capability and puts you in a submenu. ip source-address [port ] SRST(config)# Enables router to receive Skinny messages on this particular port. The default port is max-ephones SRST(config)# Defaults to 0. Maximum phones that will be allowed to register. max-dn SRST(config)# Defaults to 0. Maximum number of directory numbers that can be configured. SRST Configuration: Four Commands

© 2004 Cisco Systems, Inc. All rights reserved. IPTT v show call-manager-fallback Router#show call-manager-fallback access-code fxo 9 default-destination pattern 4312 dialplan-pattern … ip source-address port 2000 keepalive 30 max-ephones 24 max-dn 48 transfer-pattern voic 35678

© 2004 Cisco Systems, Inc. All rights reserved. IPTT v show call-manager-fallback all SRST# Displays the detailed configuration of all the Cisco IP phones, voice ports, and dial peers of the Cisco SRST router. show call-manager-fallback dial-peer SRST# Displays the output of the dial peers of the Cisco SRST router.xxx. show call-manager-fallback ephone-dn SRST# Displays Cisco IP phone destination number. show call-manager-fallback voice-port SRST# Displays output for the voice ports. SRST Monitoring and Maintaining: Commands

© 2004 Cisco Systems, Inc. All rights reserved. IPTT v Summary A gateway is the interface between the data network, IP WAN, and PSTN. When troubleshooting PSTN issues, start at Layer 1 and work up to Layer 3. Before troubleshooting a PSTN issue, isolate whether the issue is between the gateway and Cisco CallManager or between the gateway and PSTN. Most common PSTN signaling issues are easily resolved. Become familiar with debug commands. Use the Cisco TAC website to review sample gateway configurations. In failure mode, the remote gateway automatically autoconfigures itself using SNAP technology. In SRST mode, IP Phones rehome with their local gateway and keep sending keepalives to the Cisco CallManager. The ccm-manager-fallback enables Cisco CallManager fallback command capability and puts you in a submenu in Cisco IOS software.

© 2004 Cisco Systems, Inc. All rights reserved. IPTT v Lesson Review 1. What is the role of a gateway? 2. Show isdn status results in the status of layer 1 Status: DEACTIVE, what should you do? 3. Show isdn status results in layer 1 Status: ACTIVE however layer 2 status: State= TEI_Assigned, what should you do? 4. What command is used to tell the remote gateway how many IP phones to expect for SRST? 5. When troubleshooting dropped calls on a gateway, you should?