HASH ElECTION with different cache server Type

the drawing shows what you explained before and what Simon says seems to be the solution. it is a pretty common setup.

but then you add information about local channels and bind addresses and such. that doesn't become more clear in the drawing unfortunately. you probably will have to show some more of about the middleware for someone to understand that part and perhaps chip in.

what kind of outbound traffic is it, perhaps that helps? i.e. can you test with a ping or something?

Yeah, the solution I provided should solve that problem as described in the picture. But there may be other issues I am not aware of.

> What I want to achieve is a completely transparent migration with zero interruption to business. Ultimately, the migration is to save money - taxpayer's money. Hope the diagram is clearer.

While you have laudable aims, you probably need to make a choice between your goals.

You can save money, and risk having disruptions, or you can accept that a seamless migration with minimal disruption will include the cost of engaging F5 Professional Services.

Even a solid discussion with your F5 Account team/F5 Sales will put you on a better footing.

While the DevCentral is a great resource, it isn't a support organisation, and if you have an issue on the day there isn't anyone to call. If the migration is critical, engage with the people who do things like this professionally. Even if it costs a bit more.