what is the difference between LTM & GTM

Let's do this in a couple of sentences. Please be aware that this is only part of the story and they do a whole lot more.

Anyway, LTM (local traffic manager) delivers applications i.e. load balancing backend servers, say web servers. This provides availability of an application in case a web server goes down and another one can pick up the load.

You could describe GTM (global traffic manager) as datacentre load balancing / redundancy and this is all based off of DNS. For example, LTMs in DC1 and LTMs in DC2 delivering the same app can be load balanced in case of datacentre failure (or even geo-location).

This is a very top level view but hope it helps. I'm sure it could've been answered more succinctly but there you go.

Please check out www.f5.com for the datasheets.

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