Troubleshoot 8440 Spectralink and the art of delegating.

Learn the 4 techniques to address call coverage ring calls.

In this post “Troubleshoot 8440 Spectralink – The Art of Delegating” you will learn the 4 techniques to help you assist the end-user find ways to fix their call coverage ring issues, while delegating tasks with different support teams to help you find solutions to the existing problem.

Have you ever found yourself trying to help a group of telecom engineers solve call coverage ring issues? And you feel that most of troubleshooting steps have been taken by the customer, leaving you with very little to do?. Well, that was exactly how I felt when I recently received a request to help one of our clients fix call coverage ring issues with their spectralink 8440 type wireless phones.

This customer was not getting the first ring coverage, whenever the first call appeared for that particular wireless SIP device. By following these 5 techniques you can isolate a similar issue.

• 1.- Ask Basic Questions
• 2.- Get to know the customer’s Network
• 3.- Verify and compare system configurations
• 4.- Solving the problem

1.- Ask Basic Questions

We tend to forget to ask simple questions when dealing with very high level experienced customers. Keep in mind they can miss vital steps on the research process that might help you fix the issue. For this customer, they noticed the first call never ran when the Wireless SIP phones (Spectralink 8440s) were in power safe mode.

As you start your investigation, ask specific questions related to which problem you are trying to solve. I needed to understand how these users were configured , whether they were using Coverage Paths, Bridged-Appearances, or dual H.323/SIP IP Registrations, etc.

Finally, have the user emulate the problem, while you are collecting traces in the system and network.

2.- Get to know the customer’s Network

The 8440 are Wireless SIP End-points registered to a SIP Server/Registrar. IP Office or Session Manager.

To start, you must know how the customer designed their wireless topology in conjunction with their LAN and VoIP functionalities. Here, you can also delegate the WiFi troubleshooting to the customer’s network administrators with help of the Vendor’s support. I worked closely with the Sales Engineer and got a new purchase order opened to have Spectralink to work with the Network administrators directly.

In case you cannot open a ticket with Spectralink or Wireless SIP developer, you can start testing the wireless network by connecting your laptop to the customer’s network with a generic SIP Softphone to simulate a real call sample and run a site survey. Understand that there are other considerations when having vendor specific devices connected to another equipment. For the 8440s 802.11N with a dual 5GHz channel is not supported by the time I wrote this post.

Other considerations are the ACLs (Access Control Lists) and Firewall within the WAPs, Network Switches and the Avaya solution.

3.- Verify and compare system configurations

Start by looking at the registration / gatekeepers to see where these SIP End-points are resident.

It is important to know the amount of IDFs that exist between the Registration Server and Cordless 8440 handset. If the customer has a maintenance contract with a specific vendor, I suggest that you open a ticket with them to have every switch configuration validated and ensure each switch has the same QoS attributes, ACLs, etc.

The 8440s get their configuration from a FTP Server, not by connecting directly to each phone user interface. Although you can download the configuration via each phone user interface, Spectralink doesn’t recommend it.

4.- Solving the problem

We had Wireless Sniffers capturing the packets leaving the Wireless network back to the network switch. As an alternative, Wireshark was capturing the Wireless network through your Wireless card.

Take into consideration the amount of WAPs in your voice topology and have your network administrator check them as well. In my case, the Wireless Network had the Firewall turned off, causing the Network Switch send a hello packet when the first call was initiated, not letting the Wireless SIP phone know what type of message was sent, this issue was fixed by turning on the Stateful Firewall which keeps sending hello packets back to the network switch even though the Wireless SIP Phone 8440 Spectralink is in power safe mode.

How about you, What type of issues are you experiencing with the 8440s?

Spectralink 8440s Deployment Guide