In which of the following situations would iBGP be the most appropriate routing mechanism? (Choose two.)
Correct Answer: A,B
Explanation/Reference:
Section: Addressing and Routing Protocols in an Existing Network Explanation Explanation:
Internal Border Gateway Protocol (iBGP) would be the most appropriate routing protocol for a router that has either a single link or redundant links to a router within the same autonomous system (AS). An AS is defined as the collection of all areas that are managed by a single organization. BGP is typically used to exchange routing information between ASes, between a company and an Internet service provider (ISP), or between ISPs. BGP routers within the same AS communicate by using internal iBGP, and BGP routers in different ASes communicate by using external BGP (eBGP).
Using eBGP would be appropriate for a router that has redundant links to a router within a different AS. For example, redundant links between a company and an ISP, or between ISPs, would most likely use eBGP.
Static routing would be the most appropriate routing mechanism for a router that has a single link to a router within a different AS. Because an interdomain routing protocol, such as BGP, can be complicated to configure and uses a large portion of a router's resources, static routing is recommended if dynamic routing information is not exchanged between routers that reside in different ASes. For example, if you connect a router to the Internet through a single ISP, it is not necessary for the router to run BGP, because the router will use this single connection to the Internet for all traffic that is not destined to the internal network.
Reference:
CCDA 200-310 Official Cert Guide, Chapter 10, Static Versus Dynamic Route Assignment, pp. 380-381