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2018-05-11

All Mediatrix Units with ISDN cards

v. 42.1.857


1 ISDN Troubleshooting

This document is destined to customers wanting to configure and troubleshoot Mediatrix ISDN gateways connected to a PSTN or a PBX ISDN Interface.

This document provides general tips on how to troubleshoot ISDN issues.

Different scenarios are analysed and suggestion of possible solutions are proposed.


2 Protocols and Connection

The Mediatrix gateways support the following protocols:

  • QSIG
  • DSS1
  • DMS100
  • NI2
  • R2
  • 5ESS
In the Europe, the DSS1 protocol is mainly used for interconnection with public carrier and QSIG is mainly used for connections with PBXs.

The R2 protocol is more specific to Central America / Latin America countries.

In North America, the most common protocols are DMS100 and NI2.

Note that the PTSN configuration can be different from carrier to carrier. Sometimes even the same carrier may have a different PSTN configuration. Connecting an ISDN gateway to a PBX can be done in point-to-point or point-to-multipoint mode. Please refer to the PBX to see if it is configured as point-to-point or point-to-multipoint.

The Mediatrix unit can be set in TE or NT mode:

  • User side (TE): implemented in ISDN terminals (phones, terminal adapters, etc.).
  • Network side (NT): implemented in the exchange switches of the network operator.
Again this configuration will depend on the configuration of the PBX. If the PBX is configured as NT, the Mediatrix unit must be configured as TE. If the PBX is configured as TE, the Mediatrix unit must be configured as NT.

Two ISDN cards are supported on Mediatrix 3000 Series:

  • PRI (Primary Rate Interface)
  • BRI (Basic Rate Interface)
PRI cards can be configured as E1 or T1 line. Generally, E1 are available in Europe and T1 in America


3 Troubleshooting Tools


3.1 Troubleshooting

The Mediatrix CPE provides several troubleshooting features such as notification messages, diagnostic traces and SIP signalling logs.

The Syslog daemon is a general purpose utility for monitoring applications and network devices with the TCP/ IP protocol. With this software, you can monitor useful messages coming from the Mediatrix CPE.

  • Diagnostic Traces are sent using the Syslog to the Technical Assistance Centre to further assist in resolving some issues such as Interoperability.
  • PCM traces are two different RTP streams made specifically to record all analog signals that are either sent or received on the analog or ISDN side of the Mediatrix device. PCM traces are an efficient tool to identify problems with:
    • Echo in your network
    • DTMF signals
    • Caller ID signals
    • Fax signals or false Fax detection
    • Message Waiting Indicator signals
    • Any other analog or digital signal
  • Statistics are collected on each port of the PRI card, on Ping/Pingv6 on the CLI or on Media. Statistics are collected on:
    • Packet loss
    • Jitter
    • Latency
    • Packet count
    • Octet count
  • Live Network Captures can be taken with the pcapture command and sent to Wireshark located on a separate terminal. The SBC can also capture the SIP/RTP traffic of a specific call, selected by rules. The Network Capture will gather information on:
    • Interoperability
    • Timing issues
  • Configuration scripts can be generated from the configuration running on the Mediatrix CPE. This provides the content of your configuration that can be used by technical support to troubleshoot your faulty configuration.


3.2 Capturing a Trace Using Wireshark

Before You Start

You must have downloaded Wireshark at the following link https://www.wireshark.org/ (Wireshark is a network protocol analyzer. It is an Open Source software released under the GNU General Public Licence. It can decode most VoIP protocols: SIP, MGCP, H.323, RTP, etc.). Select the Windows version. Make sure to install winpcap and read the instructions.

If you are taking a trace on a switch, the port of the switch connected to the PC must be configured to mirror the port connected to the Mediatrix unit. Alternatively, you could use a hub, which should be connected to both the PC running Wireshark and the Mediatrix unit.

Otherwise you will not capture the packets from the unit.

Steps

  1. In the Capture menu, select Capture Options.
  2. In the Capture selection list, select the Ethernet network adapters to use.
  3. In the (Display) Options section, select the Update list of packet in real time check box.
  4. Select the Automatic scrolling in live capture check box.
  5. If troubleshooting a random problem happening weekly, select the Use multiple files check box.

    Note

    For the latest Wireshark release, this can be configured via Capture/Options/Ouput/Create a new file automatically after…

Result

In Wireshark release 2.2.0

In older Wireshark releases


3.3 Enabling Syslog Menu

Context

If you are not familiar with the meaning of the fields and buttons, click Show Help, located at the upper right corner of the Web page. When activated, the fields and buttons that offer online help will change to green and if you hover over them, the description will be displayed.

Steps

  1. Go to System/Syslog.
  2. In the Remote Host field, set the IP address of the PC running the syslog daemon or Wireshark.
  3. In the Syslog Configuration table, set Diagnostic Traces to Enable.

Result


3.4 Enabling Syslog Filters

Before You Start

Must have completed the task Enabling Syslog Menu

Context

If you are not familiar with the meaning of the fields and buttons, click Show Help, located at the upper right corner of the Web page. When activated, the fields and buttons that offer online help will change to green and if you hover over them, the description will be displayed.

Steps

  1. Go to System/Syslog.
  2. In the Syslog Configuration table, click Edit next to Filter
  3. In the Module table, set each module's type of syslog traces you want to receive.

Result


4 Physical Link Down


4.1 Auto-Detecting and Auto-Configuring ISDN Interfaces

Context

Note

Some parameters cannot be auto configured. For example, the clock mode is configured according to the endpoint type, master for NT and slave for TE.

If you are not familiar with the meaning of the fields and buttons, click Show Help, located at the upper right corner of the Web page. When activated, the fields and buttons that offer online help will change to green and if you hover over them, the description will be displayed.

Steps

  1. Go to ISDN/Status.
  2. In the Automatic Configuration table, click .

    Note

    Launching the Automatic Configuration may terminate abruptly all ongoing ISDN calls. The auto-configuration may take some time to complete and some of the current ISDN configuration settings might be replaced by new values.

Next Step

4.2 Configuring ISDN Preset

4.2 Configuring ISDN Preset

Context

If you are not familiar with the meaning of the fields and buttons, click Show Help, located at the upper right corner of the Web page. When activated, the fields and buttons that offer online help will change to green and if you hover over them, the description will be displayed.

Steps

  1. Go to ISDN/Status.
  2. In the ISDN Preset Configuration table, set the following parameters:
    1. Using the dropdown menu, select a Local Preset
    2. Using the Preset Name field, give a name to the preset.
  3. Click Apply.

Result

Next Step

4.3 Verifying BRI Connection

4.3 Verifying BRI Connection

Steps

  1. Check the cable on your BRI interface.

    Note

    On a 4400, you can use a straight Ethernet cable. However on a 3400 in NT mode, you will need to use a BRI cross-over cable

  2. Verify the cable length.

    Note

    The cable length between the Mediatrix gateway and the PBX must not exceed 600 metres

    For short Bus application (all terminals / wall-plugs are put in parallel at arbitrary positions of the bus): max 120 metres.

    For extended bus installation (all terminals / wall-plugs are hooked in parallel on the bus on the last 30 to 50 metres of the bus): max 450 metres.

    Proper termination of the ISDN bus / ISDN line on both ends with 100 Ohms is mandatory.

Next Step

4.4 Verifying PRI Connection

4.4 Verifying PRI Connection

Steps

  1. Check the cable on your PRI interface.
  2. Straight cable versus PRI Cross-over.

Next Step

4.5 Modifying Port Pinout

4.5 Modifying Port Pinout

Context

If you are not familiar with the meaning of the fields and buttons, click Show Help, located at the upper right corner of the Web page. When activated, the fields and buttons that offer online help will change to green and if you hover over them, the description will be displayed.

Steps

  1. Go to ISDN/Primary Rate Interface.

    Note

    Not all PRI and/or BRI platforms support Port Pinout.

  2. In the Interface Configuration table, set the Port Pinout to reflect your configuration.

Result


5 Signalling Down Troubleshooting

Make sure you have correctly configured the following:
  • Endpoint Type
  • Signalling Protocol
  • Line Coding
  • Line Framing
On some BRI connections, the Signaling status can be Down even when the link is functional. When the variable Link Establishment is at its default setting “On Demand”, the signaling link will be seen as up only when calls occur.
If the link is correctly configured, we suggest trying a call in both directions even if the Signaling Status is Down.

6 Troubleshooting Failed Calls when Physical and Signalling Status is up


6.1 Troubleshooting SIP to ISDN Calls

Context

If you are not familiar with the meaning of the fields and buttons, click Show Help, located at the upper right corner of the Web page. When activated, the fields and buttons that offer online help will change to green and if you hover over them, the description will be displayed.

Steps

  1. Go to Call Router/Route Config to verify if a route from a SIP gateway to an ISDN interface is configured.
  2. Go to ISDN/Primary Rate Interface, and set Calling Name Max Length to 0.

    Note

    Some providers do not accept User-to-user information (UUI) to be sent in setup messages. Any setup containing a UUI Information Element (IE) will be rejected by the provider, most likely with an ISDN Status message. One reason for this is that this feature might not be provided for free.

  3. Verify the setup sent to the ISDN interface by looking at the syslog messages.
  4. Go to ISDN/Primary Rate Interface and set Preferred Encoding Scheme to G.711 u-law

    Note

    By default, the Mediatrix units are configured to use the a-law codec as encoding scheme in ISDN SETUP messages. A-law is usually used in Europe. Some North-American providers and PBX reject the SETUP message unless it uses the u-law codec


6.2 Party Number Parameters Default Value

The Dgw v2.0 Application sets the following default values:
SIP to ISDN Calls Default value
TON (called and calling) Unknown
NPI (calling and called) Unknown
SI (calling) User-side: not-screened Network-side: network
ITC (calling) 3.1 kHz audio
PI (calling)
  1. When the Calling Party Number E.164 is missing: interworking. In this case, this value overrides any value set by the call router.
  2. When CLIR is enabled (user-side only): restricted. In this case, this value overrides any value set by the call router.
All other cases: allowed. This is the default value if the two cases above do not apply and no value has been set by the call router.

6.3 Troubleshooting Generic Non-Working Calls

Context

If you are not familiar with the meaning of the fields and buttons, click Show Help, located at the upper right corner of the Web page. When activated, the fields and buttons that offer online help will change to green and if you hover over them, the description will be displayed.

Steps

  1. Go to ISDN/Interop.
  2. In the Interop Configuration table, set Progress Indicator In Call Proceeding to Disable

Result


6.4 Troubleshooting ISDN to SIP Calls

Context

If you are not familiar with the meaning of the fields and buttons, click Show Help, located at the upper right corner of the Web page. When activated, the fields and buttons that offer online help will change to green and if you hover over them, the description will be displayed.

Steps

  1. Go to Call Router/Route Config to verify if a route from an ISDN interface to a SIP gateway is configured.
  2. Using syslog traces,verify if a SIP INVITE was generated by the gateway after it received the ISDN Setup from the ISDN interface.

    Note

    SIP debug must be enabled.

  3. Verify if the provider is sending a ISDN Setup message without the Called Number, with an empty Called number or only part of the Called number (last 4 digits for example). If this is the case, it is possible, via the call router, to manipulate the Called number before it is sent via SIP.

7 Enabling Calling Line Information Presentation

Context

If you are not familiar with the meaning of the fields and buttons, click Show Help, located at the upper right corner of the Web page. When activated, the fields and buttons that offer online help will change to green and if you hover over them, the description will be displayed.

Steps

  1. Go to ISDN/Services.
  2. From the Select Interface drop-down menu, select the interface you want to configure.
  3. In the Services Configuration table, set Facility Services to Enable.
  4. Set Calling Line Information Presentation to Enable.
  5. In the MSN field, enter the numbers that will be allowed when a call is incoming from the SIP side.

    Note

    Please refer to Show Help to apply the appropriate syntax.

  6. From the Apply To The Following Interfaces section, select the interfaces for which the configuration will be applied to.
  7. Click Apply.

Result

Support of ISDN FACILITY messages will be enabled.


8 Disabling Double DTMF

By default, Mediatrix units listen for out-of-band and inband DTMF. Some ISDN links provide, for the same DTMF, an out-of-band and inband signal, resulting in two DTMFs being sent to the SIP proxy.

Context

If you are not familiar with the meaning of the fields and buttons, click Show Help, located at the upper right corner of the Web page. When activated, the fields and buttons that offer online help will change to green and if you hover over them, the description will be displayed.

Steps

  1. Go to ISDN/Primary Rate Interface.
  2. Using Select Interface drop down menu, select the interface you want to configure.
  3. In the Interface Configuration table, set Inband DTMF Dialing to Disable.
  4. Click Apply.

Result


9 Country-Provider Specific Configuration - France

  • Connection to France Telecom

    In France, the prevalent protocol is VN6 (a variant of ISDN protocol)

    If you are having issues with the ISDN connection, verify with your ISDN provider if it is possible to set the ISDN link to Euro ISDN.


10 Copyright Notice

Copyright © 2018 Media5 Corporation.

This document contains information that is proprietary to Media5 Corporation.

Media5 Corporation reserves all rights to this document as well as to the Intellectual Property of the document and the technology and know-how that it includes and represents.

This publication cannot be reproduced, neither in whole nor in part, in any form whatsoever, without written prior approval by Media5 Corporation.

Media5 Corporation reserves the right to revise this publication and make changes at any time and without the obligation to notify any person and/or entity of such revisions and/or changes.