IP Routing

Routing Information Protocol (RIP)

A dynamic protocol that uses distance-vector routing algorithms to decipher which route to send data packets. It uses hop count as a routing metric to find best path.

gateway

A node that handles communication between its LAN and other networks

gateway router

A router that connects an autonomous system with an outside network—for example, the router that connects a business to its ISP.

Inter - AS policy

Admin wants control over how its traffic routed, who routes through its net. ( policy may dominate over performance ).

Open Shortest Path First (OSPF)

An interior gateway routing protocol developed for IP networks based on the shortest path first or link-state algorithm.

direct routing

Both source and destination are located in the same subnetwork

link-state protocol

Establishes a relationship with a neighboring router and uses route advertisements to build routing tables.

Boarder Gateway Protocol (BGP)

Internet exterior gateway protocol that allows routing path decisions (between ASs) that ARE NOT only based on "minimal distance". Its a de-facto standard which uses distance vector routing algorithm.

Multihomed AS

Large corporation (multiple links but no transit).

Transit AS

Provider

Gateway-to-Gateway Protocol (GGP)

Routes datagrams between internet gateways( using distance vector routing).

Intra-AS policy

Single admin, no policy decisions needed.( can focus on performance )

Stub AS

Small corporation (only one link to internet).

inter-AS routing

routing protocols established outside of an autonomous system. The routing algorithms and protocols that operate between gateway routers.

Intra-AS routing

routing protocols that are established within an autonomous system.

indirect routing

source and destination located on different networks