A very large enterprise customer is migrating from EIGRP to IS-IS. What is your main concern in regards to changes in the path packets take after the migration is complete?

Redistribution points are a concern during the transition phase when both protocols coexist, not after full migration to IS-IS is complete.

EIGRP calculates its composite metric primarily using bandwidth and delay, with lower-bandwidth links weighted more heavily in the formula. IS-IS uses a simpler, administratively assigned cost (default 10 for all interfaces regardless of bandwidth), so the SPF shortest-path calculation may produce completely different results post-migration, causing unexpected traffic path shifts across the network.

Area size in IS-IS affects flooding scope and scalability but does not directly determine which paths packets will take between endpoints.

The number of prefixes impacts memory and convergence time but does not directly determine the paths packets take after the metric-based SPF calculation.