CSS Keepalives

[jguidry]

Hello,

My client is asking if there is a best practices for deciding on what method of keepalives to use. I have search all of Cisco for this type of document or discussion. Is there such a guide in deciding which methods to use based on certain configurations or circumstances?

Any help would be appreciated.

Jerry

[Gilles Dufour]

Jerry,

there is no such guide.

It's really dependent on what you need and what you have.

Do you want to monitor the application itself or just see if the server is still alive ?

Do you have many servers [and so require many keealive] ?

How fast do you want to detect a server down ?

In a perfect world and a CSS with no CPU limit, you would check the application itself every 3 seconds.

For example, for HTTP, you will make sure you can send an HTTP request and get a HTTP 200 ok response.

But if you have too many servers, you may just want to try to open a tcp connection with the server.

And if you really have a lot of servers and the impact on cpu is too big with previous kal, you would simply use an icmp keepalive.

So the best is to be as close as possible to the application.

Regards,

Gilles.