Keepalive Frequencys

[Sbutzek]

Hello,

we have a Network with about 200 Loadbalanced Servers behind a CSS 11506.

We have about 130 Keepalives doing HTTP Get Requests.

The others are some TCP, Scripted or HTTP Head Keepalives.

I'm thinking about what keepalive frequency would fit in such an enviroment.

There is a default of 5 seconds? So is it well, to do such a large number of keepalives every 5 seconds?

Not sure, what dp other customers use in frequencys?

Does Cisco recommend some values?

In the config guides , is written that the css does alter the configured keepalive frequency if there are to much keepalives in a small gap. I've never seen such a altered config?

Anyone else?

Sven

[vmoopeung]

The keepalive process is the information-collection mechanism of an advanced GSLB solution. A keepalive is a specific interaction, or "handshake," between two devices using a commonly supported protocol. A keepalive tests if a specific protocol stack on a networking device, such as a server, router, or switch, is functioning properly. The logic of a keepalive is: A successful handshake means the target device is available, active, and able to receive traffic. A failed handshake means the target device is unavailable and inactive. This technique allows the device issuing a keepalive to understand the operational status of the device responding to the keepalive.

The most common keepalive is an Internet Control Message Protocol (ICMP) ping, documented in RFC 792. With a simple Layer 3 ping, if the device issuing the ping receives a proper response it knows two things: The Layer 3 network between the two devices is working properly, and the Layer 3 protocol stack on the device receiving the ping is active. An intelligent GSLB device will have a full suite of keepalives capable of supporting a wide range of protocols.

http://www.cisco.com/en/US/products/hw/contnetw/ps4162/products_configuration_example09186a00801f230e.shtml