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Step 9 Use the show voice iec description command to display the IEC definition:

Router> show voice iec description 1.1.179.10.24.6

    IEC Version: 1

    Entity: 

    Category: 179 (External communication Error)

    Subsystem: 10 (AFSAPP)

    Error: 24 (Digit collect failed)

    Diagnostic Code: 6

IEC field definitions pinpoint the problem. Category code 179 indicates an external communication error, and an error code 24 indicates digit collection failure. For more information on IEC field definitions, see the "Internal Error Code Notation" section.

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Troubleshooting Socket Failures

The following example, which describes a TCP session failure, shows how errors detected by the gateway can be used to troubleshoot other devices on the VoIP network.

Symptom

An inbound call from an IP phone to the H.323 gateway fails.

Problem Description

A call is initially routed to the gateway and fails when a TCP session to Cisco CallManager session target cannot be established. The router pings Cisco CallManager, sending a TCP synchronization packet and receiving an ICMP destination unreachable error. Cisco CallManager cannot be pinged because the Cisco CallManager IP address is incorrect. After the IP address for Cisco CallManager is corrected, a second call fails, due to a different socket error. The router tries to establish another TCP session and sends an H225 setup message but Cisco CallManager drops the connection.

Troubleshooting Tasks

Perform the following steps to determine the reasons for both call failures.

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Step 1 Use the voice iec syslog command to enable display of IECs as they are encountered in real-time.

Step 2 Use the voice iec statistics type iec command to configure the collection of IEC statistics.

Step 3 Use the show running-config command to verify IEC, ISDN, and dial-peer configuration, as shown in the following partial sample output:

Router> show running-config

Building configuration...

Current configuration : 3466 bytes

!

The following lines show the IEC configuration:

voice service voip 

!

voice iec syslog

no voice hpi capture buffer

no voice hpi capture destination 

voice statistics type iec

!

!

The following lines show the T1 configuration:

controller T1 0

 framing esf

 clock source line primary

 linecode b8zs

 cablelength short 133

 pri-group timeslots 1-24

!

The following lines show the ISDN configuration:

interface Serial0:23

 no ip address

 no logging event link-status

 isdn switch-type primary-ni 

 isdn incoming-voice modem

 no cdp enable

!

ivoice-port 0:D

!

The following lines show the dial-peer configuration, including the destination gateway IP address of Cisco CallManager:

dial-peer voice 1 pots

 incoming called-number

 direct-inward-dialed

 port 0:D

!

dial-peer voice 2 voip

 destination-pattern 83101

 session target ipv4:10.1.1.1

 dtmf-relay h245-alphanumeric

 codec g711ulaw

 ip qos dscp cs5 media

!

!

end

Step 4 Use the debug isdn q931 command to display information about call setup and teardown of ISDN network connections.

Router# debug isdn q931

Aug 19 01:46:02.886: ISDN Se0:23 Q931: RX <- SETUP pd = 8  callref = 0x022D 

        Bearer Capability i = 0x8090A2 

                Standard = CCITT 

                Transer Capability = Speech  

                Transfer Mode = Circuit 

                Transfer Rate = 64 kbit/s 

        Channel ID i = 0xA98381 

                Exclusive, Channel 1 

        Calling Party Number i = 0x2181, '4085550111' 

                Plan:ISDN, Type:National 

        Called Party Number i = 0x80, '83101' 

                Plan:Unknown, Type:Unknown

The following lines show the IEC and specify a network problem.

Aug 19 01:46:03.342: %VOICE_IEC-3-GW: H323: Internal Error (SETUP send sock fail): 
IEC=1.1.186.5.83.0 on callID 14 GUID=B99ACE6ED11D11D7801500B0640E6622

Aug 19 01:46:03.350: ISDN Se0:23 Q931: TX -> CALL_PROC pd = 8  callref = 0x822D 

        Channel ID i = 0xA98381 

                Exclusive, Channel 1

Aug 19 01:46:03.362: ISDN Se0:23 Q931: TX -> DISCONNECT pd = 8  callref = 0x822D 

        Cause i = 0x80A6 - Network out of order

Aug 19 01:46:03.374: ISDN Se0:23 Q931: RX <- RELEASE pd = 8  callref = 0x022D 

        Cause i = 0x82E4 - Invalid information element contents

Aug 19 01:46:03.374: ISDN Se0:23 Q931: TX -> RELEASE_COMP pd = 8  callref = 0x822D

Step 5 Use the following commands to further isolate the problem:

•The show voice iec description command displays the IEC definition.

•The debug ip tcp transaction command displays output for packets the router sends and receives.

•The debug cch323 h225 command provides the trace of the state transition of the H.225 state machine based on the processed events.

The following partial sample outputs from each command help you to isolate the cause of the network out of order message:

In the following example, the IEC definition indicates a category code of 186, a signaling socket failure, and shows that an error occurred during the SETUP PDU operation. The explanation for the error code 83 states that this error can happen if the remote IP address is a reachable address for pinging but is not a valid H.323 endpoint.

Router# show voice iec description 1.1.186.5.83.0

    IEC Version: 1

    Entity: 1

    Category: 186

    Subsystem: 5 

    Error: 83 

    Diagnostic Code: 0

Because the IEC specifies a signaling socket failure as the reason for call failure, you should enable the following debug commands to get more information.

Router# debug ip tcp transaction

TCP special event debugging is on

Router# debug cch323 h225

H225 State Machine tracing is enabled

Router# terminal monitor

% Console already monitors

Router#

Aug 19 01:46:28.746: ISDN Se0:23 Q931: RX <- SETUP pd = 8  callref = 0x022E 

        Bearer Capability i = 0x8090A2 

                Standard = CCITT 

                Transer Capability = Speech  

                Transfer Mode = Circuit 

                Transfer Rate = 64 kbit/s 

        Channel ID i = 0xA98381 

                Exclusive, Channel 1 

        Calling Party Number i = 0x2181, '4085551090' 

                Plan:ISDN, Type:National 

        Called Party Number i = 0x80, '83101' 

                Plan:Unknown, Type:Unknown

Aug 19 01:46:29.198: TCB63D2DAC8 created

Aug 19 01:46:29.198: TCB63D2DAC8 setting property TCP_PID (8) 63A2C044

Aug 19 01:46:29.198: TCB63D2DAC8 setting property TCP_NO_DELAY (1) 63A2C048

Aug 19 01:46:29.198: TCB63D2DAC8 setting property TCP_TOS (11) 63A2C070

Aug 19 01:46:29.198: TCB63D2DAC8 setting property TCP_NONBLOCKING_WRITE (10) 63A2C0D0

Aug 19 01:46:29.198: TCB63D2DAC8 setting property TCP_NONBLOCKING_READ (14) 63A2C0D0

Aug 19 01:46:29.198: TCB63D2DAC8 setting property unknown (15) 63A2C0D0

Aug 19 01:46:29.198: TCB63D2DAC8 setting property TCP_NO_DELAY (1) 63A2C08C

Aug 19 01:46:29.198: TCB63D2DAC8 setting property TCP_ALWAYSPUSH (17) 63A2C08C

Aug 19 01:46:29.198: TCB63D2DAC8 bound to 172.16.13.16.11005

Aug 19 01:46:29.198: TCP: sending SYN, seq 3651477840, ack 0

Aug 19 01:46:29.198: TCP0: Connection to 10.1.1.1:1720, advertising MSS 536

Aug 19 01:46:29.198: TCP0: state was CLOSED -> SYNSENT [11005 -> 10.1.1.1(1720)]

The following lines show the 10.1.1.1 CallManager address is unreachable as it is configured, and the network out of order IEC is generated:

Aug 19 01:46:29.202: TCP0: ICMP destination unreachable received

!

!

!Aug 19 01:46:29.206: %VOICE_IEC-3-GW: H323: Internal Error (SETUP send sock fail): 
IEC=1.1.186.5.83.0 on callID 16 GUID=C904C18BD11D11D7801600B0640E6622

Aug 19 01:46:29.206: TCB 0x63D2DAC8 destroyed

Aug 19 01:46:29.206: //16/C904C18B8016/H323/run_h225_sm: Received event H225_EV_CONN_LOST 
while at state H225_IDLE

Aug 19 01:46:29.214: ISDN Se0:23 Q931: TX -> CALL_PROC pd = 8  callref = 0x822E 

        Channel ID i = 0xA98381 

                Exclusive, Channel 1

Aug 19 01:46:29.218: //16/C904C18B8016/H323/run_h225_sm: Received event H225_EV_RELEASE 
while at state H225_IDLE

Aug 19 01:46:29.218: //16/C904C18B8016/H323/cch323_h225_set_new_state: Changing from 
H225_IDLE state to H225_IDLE state

Aug 19 01:46:29.226: ISDN Se0:23 Q931: TX -> DISCONNECT pd = 8  callref = 0x822E 

        Cause i = 0x80A6 - Network out of order

!

!

Step 6 Use the show ip route command to display static routes, then use the ping command to check network connectivity to the destination address 10.1.1.1 using the ping command.

Router> show ip route

Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP

       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area 

       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2

       E1 - OSPF external type 1, E2 - OSPF external type 2

       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2

       ia - IS-IS inter area, * - candidate default, U - per-user static route

       o - ODR, P - periodic downloaded static route

Gateway of last resort is 172.16.13.3 to network 0.0.0.0

     172.16.0.0/27 is subnetted, 1 subnets

C       172.16.13.0 is directly connected, Ethernet0

S*   0.0.0.0/0 [1/0] via 172.16.13.3

The following lines show that the reason for Cisco CallManager TCP session failure is the incorrect 10.1.1.1 IP address:

Router# ping 10.1.1.1

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 10.1.1.1, timeout is 2 seconds:

..U.U

Success rate is 0 percent (0/5)

Router# ping 10.1.1.1      

Step 7 Configure the correct IP address for Cisco CallManager and verify the configuration using the show running-config command.

Router# config term

Enter configuration commands, one per line.  End with CNTL/Z.

Router(config)# dial-peer voice 2

Router(config-dial-peer)# session target ipv4:172.31.85.107

Router(config-dial-peer)# end

Router# show running-config

!

!

!

dial-peer voice 2 voip

 destination-pattern 83101

 session target ipv4:172.31.85.107

 dtmf-relay h245-alphanumeric

 codec g711ulaw

 ip qos dscp cs5 media