Substantive commentary
Internet Protocol (IP) routing entails the establishment of communication links in the network and selecting paths along which to send network traffic. As explained in the answer, the routing occurs in two ways direct and indirect routing, additionally it should be noted that the term IP routing is an umbrella term for a set of protocols which are followed by data so they can move from one point to another. The data is routed from the source to the destination via a series of routers, the IP routing protocols facilitate the correlation between the forwarding table in the source with destination table.
The examples of these protocols that are not mentioned in the response include: BGP (border gateway protocol), OSPF (open shortest path first) protocol, RIP (routing information protocol) and the IS –IS protocol. In IP routing, the IP address in the packet header is the major determinant of the transmission of packets in a network. It determines the next hop to be transmitted to in a network.
An important aspect that should have been addressed by the answer is how the internet routing protocols handles routing in an internet setting. This is achieved by creation of Autonomous systems (AS) within the internet. The AS contains a group of routers that are centrally controlled. Exchange of routing information in the AS uses a common protocol. A corporate network or an ISP network is often referred to as an AS. These AS could be further classified as STUB AS, multihomed AS and Transit AS. Routes within an individual AS are calculated by the internal gateway protocol, the external gateway protocol. It then distributes the routes between the different ASs. Generally the answer provided best describes various aspects of IP routing protocols and adequately answers the question asked.
References
Metaswitch networks. (2012). Network technologies. Retrieved on 10th September 2012, from Metaswitch Networks: http://network-technologies.metaswitch.com/ip-routing-unicast/what-is-ip-routing.aspx
