Table Of Contents
Troubleshooting Digital Voice Interfaces to the IP Network
Digital voice ports are found at the intersection of a packet voice network and a digital, circuit-switched telephone network. Digital voice telephony interfaces include T1 or E1 channel-associated signaling (CAS), ISDN primary-rate interface (PRI) or basic rate interface (BRI), and E1 R2 signaling.
To troubleshoot digital voice interfaces, see the following sections:
If you are troubleshooting a connection to a PBX, you might the PBX interoperability notes useful. These notes contain configuration information for Cisco gateways and several types of PBXs. To access these notes, use the following website:
Checking the Hardware
Digital voice interface hardware connects a router or access server to a line from a circuit-switched telephony device in a PBX or the public switched telephone network (PSTN).
Troubleshoot digital voice hardware by checking the following:
Software Compatibility
To ensure that your card is compatible with your software, check the following:
•
For network modules inserted into Cisco modular access routers, refer to the compatibility tables in the "Overview of Cisco Network Modules" chapterin the Cisco Network Modules Hardware Installation Guide.
For network modules inserted into Cisco modular access routers, refer to the compatibility tables in the "Overview of Cisco Network Modules" chapterin the Cisco Network Modules Hardware Installation Guide.
•For interface cards inserted into Cisco modular access routers, refer to the compatibility tables in the "Overview of Cisco Interface Cards" chapter in the Cisco Interface Cards Installation Guide.
For interface cards inserted into Cisco modular access routers, refer to the compatibility tables in the "Overview of Cisco Interface Cards" chapter in the Cisco Interface Cards Installation Guide.Cabling
Cabling for the digital ports varies by platform:
•Cisco 1600 series, Cisco 1700 series, Cisco 2600 series, Cisco 3600 series, Cisco 3700 series, and Cisco ICS 7750 platforms that use the Multiflex Trunk Interface card use an RJ-48C cable. Refer to the Cisco Interface Card Hardware Installation Guide for information about digital Cisco interface cards.
Cisco 1600 series, Cisco 1700 series, Cisco 2600 series, Cisco 3600 series, Cisco 3700 series, and Cisco ICS 7750 platforms that use the Multiflex Trunk Interface card use an RJ-48C cable. Refer to the Cisco Interface Card Hardware Installation Guide for information about digital Cisco interface cards.
•Cisco 7200 VXR platforms use RJ-48C cables for the port adapter. See the MIX-Multichannel T1/E1 Port Adapter Installation and Configuration Guidefor more information.
Cisco 7200 VXR platforms use RJ-48C cables for the port adapter. See the MIX-Multichannel T1/E1 Port Adapter Installation and Configuration Guidefor more information.
•Cisco AS5300 universal access servers use RJ-45 cables for the T1 or E1 interface. A VoIP feature is also required for voice traffic. See the Cisco AS5300 Module Installation Guide.
Cisco AS5300 universal access servers use RJ-45 cables for the T1 or E1 interface. A VoIP feature is also required for voice traffic. See the Cisco AS5300 Module Installation Guide.
•Cisco AS5350 and 5400 universal gateways use RJ-45 cables for the four-port card and a 36-pin cable to RJ-45 interface for the eight-port card. For more information about cabling these platforms, see the "Cabling Specifications" chapter of the Cisco AS5350 and AS5400 Universal Gateway Card Installation Guide.
Cisco AS5350 and 5400 universal gateways use RJ-45 cables for the four-port card and a 36-pin cable to RJ-45 interface for the eight-port card. For more information about cabling these platforms, see the "Cabling Specifications" chapter of the Cisco AS5350 and AS5400 Universal Gateway Card Installation Guide.T1/E1 Trunk and Digital Voice Port Pinouts (RJ-48)
Figure 32 shows the RJ-48 connector wiring for the T1/E1 trunk cable and the digital voice port cable; Table 32 lists the pinouts.
Figure 32 RJ-48-to-RJ-48 T1/E1 Cable Wiring
Pin 1
|
Signal
|
|---|---|
1
|
RX (input)
|
2
|
RX (input)
|
3
|
-
|
4
|
TX (output)
|
5
|
TX (output)
|
6
|
-
|
7
|
-
|
8
|
-
|
1 Any pin not referenced on a connector is not connected.
|
T1/E1 Trunk and Digital Voice Port Pinouts (RJ-45)
RJ-45 Pin
|
Description
|
|---|---|
1
|
RX tip
|
2
|
RX ring
|
3
|
RX shield
|
4
|
TX tip
|
5
|
TX ring
|
6
|
TX shield
|
7
|
-
|
8
|
-
|
Shutdown Port
If the port is not operational, check to make sure the port is not shut down. Enter the show voice port command with the voice port number that you are troubleshooting, which tells you:
•If the voice port is up. If it is not, use the no shutdown command to make it active.
If the voice port is up. If it is not, use the no shutdown command to make it active.
•What parameter values have been set for the voice port, including default values. (these do not appear in the output from the show running-config command.) If these values do not match those of the telephony connection you are making, reconfigure the voice port.
What parameter values have been set for the voice port, including default values. (these do not appear in the output from the show running-config command.) If these values do not match those of the telephony connection you are making, reconfigure the voice port.Checking the Digital Signal Processors
Digital signal processors (DSPs) enable Cisco platforms to efficiently process digital voice traffic. The following symptoms can be attributed to DSP hardware or software issues:
•No audio heard by either party or one-way audio on the voice path after the call is connected.
No audio heard by either party or one-way audio on the voice path after the call is connected.
•Call setup failure, such as the inability to detect or transmit proper Channel Associated Signaling (CAS) state transitions.
Call setup failure, such as the inability to detect or transmit proper Channel Associated Signaling (CAS) state transitions.
•Channels are stuck in the PARK state and cannot be used.
Channels are stuck in the PARK state and cannot be used.
•Error messages on the console or in the router log complain of DSP timeouts.
Error messages on the console or in the router log complain of DSP timeouts.
To check your DSPs, use the following sections:
Voice DSP Control Message Logger
This section contains the following information:
Caution Using the logger feature in a production network environment increases CPU and memory usage on the gateway.
Using the logger feature in a production network environment increases CPU and memory usage on the gateway.
Note We recommend that you work closely with your Cisco representative to use this feature. If you are experiencing problems with certain voice calls, the engineering team at Cisco might ask you to capture the control messages using the voice DSP logger. You can capture these messages by turning on the logger, repeating the problematic calls, and capturing the logs. Only Cisco engineers can determine if you should send the logs in for further review.
We recommend that you work closely with your Cisco representative to use this feature. If you are experiencing problems with certain voice calls, the engineering team at Cisco might ask you to capture the control messages using the voice DSP logger. You can capture these messages by turning on the logger, repeating the problematic calls, and capturing the logs. Only Cisco engineers can determine if you should send the logs in for further review.Message Logger Overview
The Voice DSP Control Message Logger feature provides improved debugging capabilities through Cisco IOS software and allows loggin of control messages that pass through the voice DSP firmware on the host port interface (HPI). The logged messages can later be examined for diagnosis of voice problems.
There are two main types of HPI messages that flow through the HPI interface: control messages and data messages. Control messages carry control information between Cisco IOS software and the DSP. Data messages carry voice data.
The Voice DSP Contol Message Logger feature captures control messages sent between the platform-independent portions of Cisco IOS software and the DSP. The HPI subsystem that is in Cisco IOS software contains the platform-independent portion of Cisco IOS software. This feature addresses the sequence and contents of the control messages. The logged messages can be checked for parameters that might cause undesirable DSP behavior including the following:
•Incorrect parameters
Incorrect parameters
•Out-of-sequence function calls
Out-of-sequence function calls
•Interactions between parameters of different HPI calls
Interactions between parameters of different HPI calls
In many cases, DSP problems have been the result of bad control messages. By logging all of these messages for offline analysis, you can better integrate and debug at-speed issues for analysis.
Message Capture
Message capture occurs when voice control messages are captured and passed between the Cisco IOS software and the DSP to a ring buffer. Some of these messages are sent in fast-path routines that run at a high priority, so the capture of the message must be done as quickly as possible. After the fast-path routine messages have been sent, a normal priority process sends the messages that are waiting in the ring buffer to off-router data storage through the Cisco IOS File System (IFS).
The size of the ring buffer is configurable through the use of the voice hpi capture command. If the ring buffer fills up faster than the normal priority process can move the messages off the router, some of the control messages are dropped.
Counters keep track of the number of messages that are waiting in the ring buffer, the number of messages that are sent, and the number of messages that are dropped. When message capture is enabled and a message arrives for which there is no buffer space, a missed-message count is started. The next time there is room for a message on the ring, the dropped-message count is included with the message data. This alerts the software that processes the messages to the missed messages, and it provides data capture feedback that helps you configure the ring buffer size to your specifications.
If messages are dropped during the capture, the ability to check the messages becomes limited. A complete capture is required for analysis.
Benefits
Improved DSP Reliability
This feature improves the reliability of DSPs by improving debug capabilities. Unexpected sequences of calls or parameters that cause DSP problems are difficult to debug because many calls can be made to the DSP before any ill effects are noticed. Systems that are running under load are more likely to encounter subtle timing-related issues that occur infrequently and are very hard to reproduce and debug. These parameters are marked as bad in HPI calls to the DSP, and they can cause undesirable DSP behavior. There fore, the logger intercepts those parameters that pass between Cisco IOS software and the DSP that can later be checked for errors.
Robust Firmware
This feature makes the T1-based DSP firmware more robust, adding debug capabilities and enabling better field support.
Restrictions
The Voice DSP Contol Message Logger feature is supported only on systems that use the HPI interface.
Configuration Tasks
See the following sections for configuration tasks for the Voice DSP Control Message Logger feature. Each task in the list is identified as either required or optional.
•Configuring the Voice DSP Control Message Logger (required)
Configuring the Voice DSP Control Message Logger (required)
•Verifying the Voice DSP Control Message Logger (optional)
Verifying the Voice DSP Control Message Logger (optional)Configuring the Voice DSP Control Message Logger
You can start the message logger by choosing the amount of memory (greater than 324 bytes) that the buffer-queueing system can allocate to the free message pool. HPI messages are captured until buffer space runs out. Once the buffer-queueing system is running, the transport process attempts to connect to a new or existing capture destination URL. A version message is written to the URL, and if the version message is accepted, any messages placed into the message queue are written to the URL. If a new URL is entered using command-line interface (CLI), an open URL is closed, and the system tries to write to the new URL. If the new URL fails, the transport process exits. The transport process is restarted when another URL is entered or the system is restarted.
To configure the message logger, use the following commands beginning in privileged EXEC mode.
SUMMARY STEPS
1. enable
enable
2. show voice hpi capture
show voice hpi capture
3. debug hpi capture
debug hpi capture
4. configure terminal
configure terminal
5. voice hpi capture buffer size
voice hpi capture buffer size
6. voice hpi capture destination url
voice hpi capture destination url
7. exit
exit
8. show voice hpi capture
show voice hpi capture
9. configure terminal
configure terminal
10. no voice hpi capture buffer 0
no voice hpi capture buffer 0
11. exit
exit
12. show voice hpi capture
show voice hpi captureDETAILED STEPS
Verifying the Voice DSP Control Message Logger
To verify and print capture status and statistics, use the show voice hpi capture privileged EXEC command. This command displays the capture status and statistics and checks that the message counter is incrementing. If messages are being dropped consistently, try increasing the buffer size.
Note If you want to stop the logger or change the buffer to another size, first set the buffer size to zero.
If you want to stop the logger or change the buffer to another size, first set the buffer size to zero.
No comments:
Post a Comment