This blog was originally started to better help me understand the technologies in the CCIE R&S blueprint; after completing the R&S track I have decided to transition the blog into a technology blog.

CCIE #29033

This blog will continue to include questions, troubleshooting scenarios, and references to existing and new technologies but will grow to include a variety of different platforms and technologies. Currently I have created over 185 questions/answers in regards to the CCIE R&S track!! Note: answers are in the comment field or within "Read More" section.

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Sunday, May 2, 2010

Question 72

What is FREEK and why would we use it?

3 comments:

Packets Analyzed said...

FREEK - Frame-relay end to end keepalives are used to monitor the status of a PVC.

You must create a map-class to use FREEK

"map-class frame-relay (name)"
"frame-relay end-to-end keepalive mode (bidirectional | request | reply | passive-reply)"

bidirectional - sends and receives keepalives
request - sends keepalives requests
reply - responds to keepalives
passive-reply - responds to keepalives but does not track errors or successes

To apply the class go to the interface
"frame-relay class (name)"

Show commands
"show frame-relay end-to-end keepalive interface"

Unknown said...

Frame-relay traditionally uses LMI to detect line status (among other things). The issue with using LMI is that the line status updates are only exchanged between the DTE and the closest DCE. This means that there could still be an issue on the remote side of the virtual circuit (VC).
FREEK addresses this limitation by verifying endpoint-to-endpoint communication using the different modes mentioned above.

With LMI, if three consecutive LMI updates are missed the VC would be considered down. How many send or receive errors have to be registered before FREEK considers the VC to be down? :D

Packets Analyzed said...

The default the keepalive timer for sending is 10 seconds and for receiving it is 15 seconds. The extra 5 seconds is to accommodate the time for the receiving end to receive and process the keepalive.

If 3 keepalives are missed FREEK will bring down the PVC. 3 Keepalives X 10seconds = 30 seconds.

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