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300-320 · Question #80

Which two options improve BGP scalability in a large autonomous system? (Choose two.)

The correct answer is A. route reflectors C. confederations. In a large BGP autonomous system, the full-mesh IBGP requirement is the primary scalability bottleneck. Route reflectors (A) solve this by allowing a central RR router to reflect routes to all clients, eliminating the need for every router to peer with every other router…

Advanced Addressing and Routing Solutions

Question

Which two options improve BGP scalability in a large autonomous system? (Choose two.)

Options

  • Aroute reflectors
  • Broute redistribution
  • Cconfederations
  • Dcommunities

How the community answered

(31 responses)
  • A
    90% (28)
  • B
    6% (2)
  • D
    3% (1)

Explanation

In a large BGP autonomous system, the full-mesh IBGP requirement is the primary scalability bottleneck. Route reflectors (A) solve this by allowing a central RR router to reflect routes to all clients, eliminating the need for every router to peer with every other router. Confederations (C) split the AS into multiple sub-ASes with EBGP-style peering between them, reducing the full-mesh requirement to within each smaller sub-AS. Route redistribution (B) does not address IBGP mesh complexity and can introduce instability. BGP communities (D) are a useful traffic-engineering tool but do not reduce the number of required BGP sessions or improve mesh scalability.

Topics

#BGP#route reflectors#confederations#scalability

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