5. Deployment Considerations

5. Deployment Considerations

Once a Route is selected for validation, it is categorized according the procedure given in Section 2. Subsequently, routing policy as discussed in Section 3 can be used to take action based on the validation state.

Policies that could be implemented include filtering routes based on validation state (for example, rejecting all "invalid" routes) or adjusting a route's degree of preference in the selection algorithm based on its validation state. The latter could be accomplished by adjusting the value of such attributes as LOCAL_PREF. Considering invalid routes for BGP decision process is a purely local policy matter and should be done with utmost care.

In some cases (particularly when the selection algorithm is influenced by the adjustment of a route property that is not propagated into Internal BGP (IBGP)) it could be necessary for routing correctness to propagate the validation state to the IBGP peer. This can be accomplished on the sending side by setting a community or extended community based on the validation state, and on the receiving side by matching the (extended) community and setting the validation state.