Explanation/Reference:
Section: Addressing and Routing Protocols in an Existing Network Explanation Explanation:
Static routing would be the most appropriate routing mechanism for a router that has a single link to a router within a different autonomous system (AS). An AS is defined as the collection of all areas that are managed by a single organization. Because an interdomain routing protocol, such as Border Gateway Protocol (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 Internet service provider (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.
External BGP (eBGP), not static routing, would be the most appropriate routing protocol for a router that has redundant links to a router within a different AS. BGP is typically used to exchange routing information between ASes, between a company and an ISP, or between ISPs. BGP routers within the same AS communicate by using internal BGP (iBGP), and BGP routers in different ASes communicate by using eBGP.
An intradomain routing protocol, such as Enhanced Interior Gateway Routing Protocol (EIGRP) or Open Shortest Path First (OSPF), would be the most appropriate routing protocol for a router that has a single link or redundant links to a router within the same AS.
Reference:
CCDA 200-310 Official Cert Guide, Chapter 10, Static Versus Dynamic Route Assignment, pp. 380-381