AWS Certified Advanced Networking – Specialty (ANS-C01)Network Management and OperationsMedium
A company is using AWS Transit Gateway to connect multiple VPCs and on-premises networks via AWS Direct Connect. They need to implement automated routing updates between their on-premises routers and the Transit Gateway. The solution must support dynamic routing and automatically propagate route changes. Which routing protocol should be configured between the on-premises routers and the Transit Gateway?
- ARIP (Routing Information Protocol)
- BBGP (Border Gateway Protocol)
- CStatic Routing
- DOSPF (Open Shortest Path First)
Show answer & explanationAnswer & explanation
Correct answer: B. BGP (Border Gateway Protocol)
BGP (Border Gateway Protocol) is the standard dynamic routing protocol used by AWS Direct Connect and AWS Site-to-Site VPN connections to exchange routing information with on-premises networks. It enables automatic propagation of route changes between the on-premises routers and the Transit Gateway, ensuring that the network always has up-to-date routing information without manual intervention.
Why the other options are wrong
- A. RIP is an older, simpler interior gateway protocol (IGP) that is less scalable and efficient than OSPF or BGP, and not supported by AWS for this purpose.
- C. Static routing requires manual configuration of each route, which is not scalable or automated for dynamic route changes.
- D. OSPF is an interior gateway protocol (IGP) typically used within an autonomous system, but AWS uses BGP for external routing with Direct Connect and VPN.
AWS Hybrid Routing Protocols
AWS uses BGP (Border Gateway Protocol) for dynamic routing between AWS network services (like Direct Connect, Site-to-Site VPN, Transit Gateway) and on-premises networks.
- BGP enables automatic exchange of routing information.
- Supports high availability and automatic failover.
- Essential for complex hybrid cloud environments with dynamic changes.
Memory trick: To 'route' between 'borders', use 'BGP'.