RE: Routing to multiple uplinks

[Deepak Jain <deepak () ai net>]

> The overall design is being driven by our rigorous application needs
> more
> than anything.
>
> The implementation is straight forward we receive a duplicate set of
> feeds
> from site A and site B and can also access various services coming from
> site
> A or site B however, at any given time a user will be sending/recieving
> data
> from one of those destinations. Never both simultaneously.  So my
> question
> what is the best way to provide this type of redundancy at the host
> level?
>
> The application will only use one target address.

You've stated two seemingly contradictory things. 1) The User decides which paths to take yet the 2) application cannot 
see more than one path. 

First, this sounds like a User issue. The application with such rigorous requirements should have the features you need 
to manage this.

Barring that... :)

The mechanism the User uses to (manually) decide which path to take should make the election and handle the switchover 
in visibility. Presumably, since your application cannot tell when its switched destinations/paths it needs to be 
notified if the network makes a VRRP/HSRP decision. This all points to the mechanism you presumably already have in 
place for manual path decisions.

If you are using your Linux box or whatever to make your path choices, simply have a script that sees if the path 
preferences have changed and use your method to notify the Application.

If you are using a Cisco (or other) dedicated router, run something on the Application box or servers that will notice 
this change (if even by querying the router) so it can proactively detect this.

You've asked for a technical suggestion but have not provided any detail about the actual constraints you have -- 
though you've implied them without context.

Deepak Jain
AiNET