X Busy Lamp Field Issues - BLF Issues

Busy Lamp Field (BLF)

BLF is an acronym for Busy Lamp Field, which is a light on an IP Phone. or a colored indicator next to a name in a softphone or web client, that tells you whether another extension connected to the same PBX is busy or not.

BLF Function Keys on IP Phones

Many popular IP phone manufacturers, such as Yealink, Polycom and Cisco, sell a variety of phones that have BLF function keys. Depending on the type of phone you have, BLF’s will either been green, flashing red, or red. If a BLF key is green, that means the extension number is free to talk. If the BLF starts to flash red, it usually means someone is calling that extension. If the BLF function key is red, it means the owner of that extension is on a call or unavailable.

BLF’s are also helpful when answering another colleagues phone. For instance, if a colleague isn’t at their desk and they receive an incoming call, someone else can pick up the call simply by clicking the flashing BLF. Additionally, you can configure BLF keys so that they are associated with the extensions of your choice, for example, the colleagues that you contact the most. Not only can you monitor who is available, but you can also use the keys as a speed dial function for your most commonly dialed extensions.

How to verify BLF is setup in OSSmosis and on the handset

We need to make sure we are attempting reboots along with clearing the user from the EW client list (NOT DHCP lease table!)

If the behavior is on a phone behind an EW 2900, please try disabling Storm Filtering on the phone.  This can be done via the menu settings.

Menu->Settings->Advanced->Network configuration->Ethernet Menu-> Storm filtering 

The next possible solution is to switch the phone to TCP. The proper procedure for updating the phone can be found at: Modifying Polycom Configuration File to Support TCP Transport Protocol

Lastly if all of the above fails, please escalate the ticket to Tier 2 and ensure you include the following in your Tier2 log note:

                Customer:

Platform:

EW:

Connection:

User:

Phone Model:

Providing this information will be helpful for us to track these behaviors as we work toward any further isolation.