Additional Routing Protocol for Overlay Routing between Group Members
Question
You are designing a Group Encrypted Transport virtual private network solution for an existing branch network.
The existing network has the following characteristics: - 50 remote sites (with an additional 30 remote sites expected over the next 3 years) - Connectivity between all sites is via Multiprotocol Label Switching Layer 3 virtual private network service from a single provider - Open Shortest Path First is the routing protocol used between provider edge and customer edge routers - The customer edge routers will become group members performing the encryption between sites Which additional routing protocol would you use for the overlay routing between the group members?
Answers
Explanations
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A. B. C. D. E. F.C.
In this scenario, we are designing a Group Encrypted Transport (GET) VPN solution for an existing branch network with 50 remote sites and an additional 30 remote sites expected over the next 3 years. The existing network is connected through Multiprotocol Label Switching (MPLS) Layer 3 virtual private network ( VPN) service from a single provider. Open Shortest Path First (OSPF) is used as the routing protocol between provider edge (PE) and customer edge (CE) routers, and the CE routers will become group members performing the encryption between sites.
The question asks for an additional routing protocol to be used for the overlay routing between group members. Overlay routing is a method of creating a virtual network on top of an existing network infrastructure. In this case, the overlay network will be the encrypted virtual private network between the group members.
Option A suggests using OSPF with a different process ID for overlay routing. While this is technically possible, it is not a recommended solution because it can lead to routing instability and increased complexity.
Option B suggests using Enhanced Interior Gateway Routing Protocol (EIGRP) for overlay routing. EIGRP is a Cisco proprietary routing protocol that is designed to work well in large networks with multiple paths. However, it is not an industry standard protocol and may not be supported by all network devices.
Option C suggests that no additional protocol is necessary for overlay routing. This is not correct because the group members need to exchange routing information to build the overlay network.
Option D suggests using External Border Gateway Protocol (EBGP) for overlay routing. This is not a recommended solution because it is typically used for exchanging routing information between different autonomous systems, not within a single network.
Option E suggests using Routing Information Protocol Version 2 (RIPv2) for overlay routing. RIPv2 is a simple distance-vector routing protocol that may work well in small networks but is not recommended for large networks because of its limited scalability.
Option F suggests using Next Hop Resolution Protocol (NHRP) for overlay routing. NHRP is a protocol used in GET VPN to enable the mapping of group members' IP addresses to their public keys. It is designed to work with GET VPN and is the recommended solution for overlay routing in this scenario.
Therefore, the correct answer is F, Next Hop Resolution Protocol (NHRP).
