CCIE CCIE Service Provider 2

Question 1

In BGP, what is the purpose of a Route Reflector (RR)?

Accepted Answer

Eliminating the need for full IBGP mesh by reflecting routes to clients

Answer

Route Reflectors allow BGP routes received from one client to be reflected to other clients, eliminating the scalability problem of requiring full IBGP mesh.

Question 2

What is Segment Routing (SR) in modern service provider networks?

Accepted Answer

A source routing architecture using segments encoded in the packet header

Answer

Segment Routing (SR) is a source-routing architecture where the ingress node encodes an explicit path as a list of segments (SIDs) in the packet header.

Question 3

Which protocol is commonly used in service provider cores for fast reroute and TE capabilities with Segment Routing?

Accepted Answer

IS-IS with SR extensions

Answer

IS-IS with SR extensions distributes Node SIDs and Adjacency SIDs throughout the SP core, enabling SR-based traffic engineering and TI-LFA fast reroute.

Question 4

In MPLS L2VPN VPLS, what is a VSI (Virtual Switching Instance)?

Accepted Answer

A virtual bridge that emulates a LAN across the MPLS backbone

Answer

A VSI (Virtual Switching Instance) in VPLS emulates a multi-point Ethernet LAN across the MPLS backbone by maintaining MAC address tables per service.

Question 5

What is the role of BGP confederations in large ISP networks?

Accepted Answer

Dividing a large AS into sub-ASes to reduce IBGP full-mesh requirements

Answer

BGP confederations split a large AS into smaller sub-ASes, with EBGP running between sub-ASes, reducing the full IBGP mesh required in the overall AS.

CCIE - Cisco Certified Internetwork Expert Practice Test

CCIE - Cisco Certified Internetwork Expert Practice Test

CCIE CCIE Service Provider 2