Question 1
Case Study:
A rapidly growing e-commerce company, 'GlobalCart', is expanding its network. They currently operate a single Autonomous System (AS 65001) with 20 routers in a full iBGP mesh. The network engineering team is struggling to manage the configuration complexity and the high number of TCP sessions. The company plans to add 30 more routers within the next year. All routers are in a single administrative domain and require full visibility of all external routes. The lead architect wants a solution that simplifies configuration, reduces the number of iBGP peerings, and avoids partitioning the AS into sub-ASes.
Which BGP scaling solution should the architect implement to meet these requirements?
Answer and explanation
Correct answer: C
Route reflectors (RRs) are the ideal solution for this scenario. They solve the n(n-1)/2 peering problem of a full mesh by allowing routers to peer only with the RRs. This drastically simplifies configuration and reduces TCP session overhead. RRs operate within a single AS, meeting the requirement to avoid sub-ASes (which confederations would require). Deploying two RRs provides redundancy. While automation helps manage a full mesh, it doesn't solve the underlying scalability issue of numerous peerings. BGP add-path is for load balancing, not scaling the control plane.
