the vip redundancy is a shared vip ip address.
This is the ip of a content rule.
The interface redundancy is like hsrp/vrrp.
You create an ip address to you assign to the interface of the CSS. This is shared ip address.
Finally, shared vip redundancy is when you want both CSS [master and slave] to be active.
Nobody uses this so I would not talk much about it.
So, what you need is a combination of vip and interface redundancy.
On the front side, you use vip redundancy.
This is where your clients are coming in.
On the backend side, you use interface redundancy.
This ip will server as the default gateway for the servers.
Regards,
Gilles.
