Routing, Routed and Non-RoutableProtocols

ROUTING PROTOCOLS

ROUTING PROTOCOLS are the software that allow routers to dynamically advertise and learn routes, determine which routes are available and which are the most efficient routes to a destination. Routing protocols used by the Internet Protocol suite include:

• Routing Information Protocol (RIP and RIP II)
• Open Shortest Path First (OSPF)
• Intermediate System to Intermediate System (IS-IS)
• Interior Gateway Routing Protocol (IGRP)
• Cisco's Enhanced Interior Gateway Routing Protocol (EIGRP)
• Border Gateway Protocol (BGP)

Routing is the process of moving data from one network to another network. Within a network, all hosts are directly accessable and do not need to pass data through a default gateway. All hosts on the same network are directly connected and can communicate directly with each other.

ROUTED PROTOCOLS

ROUTED PROTOCOLS are nothing more than data being transported across the networks. Routed protocols include:

• Internet Protocol
  • Telnet
  • Remote Procedure Call (RPC)
  • SNMP
  • SMTP
• Novell IPX
• Open Standards Institute networking protocol
• DECnet
• Appletalk
• Banyan Vines
• Xerox Network System (XNS)

Outside a network, specialized devices called ROUTERS are used to perform the routing process of forwarding packets between networks. Routers are connected to the edges of two or more networks to provide connectivity between them. These devices are usually dedicated machines with specialized hardware and software to speed up the routing process. These devices send and receive routing information to each other about networks that they can and cannot reach. Routers examine all routes to a destination, determine which routes have the best metric, and insert one or more routes into the IP routing table on the router. By maintaining a current list of known routes, routers can quicky and efficiently send your information on it's way when received.

There are many companies that produce routers: Cisco, Juniper, Bay, Nortel, 3Com, Cabletron, etc. Each company's product is different in how it is configured, but most will interoperate so long as they share common physical and data link layer protocols (Cisco HDLC or PPP over serial, Ethernet etc.). Before purchasing a router for your business, always check with your Internet provider to see what equipment they use, and choose a router which will interoperate with your Internet provider's equipment.

NON-ROUTABLE PROTOCOLS

NON-ROUTABLE PROTOCOLS cannot survive being routed. Non-routable protocols presume that all computers they will ever communicate with are on the same network (to get them working in a routed environment, you must bridge the networks). Todays modern networks are not very tolerant of protocols that do not understand the concept of a multi-segment network and most of these protocols are dying or falling out of use.

• NetBEUI
• DLC
• LAT
• DRP
• MOP