Presentation on theme: "ARP AND RARP ROUTED AND ROUTING Tyler Bish. ARP There are a variety of ways that devices can determine the MAC addresses they need to add to the encapsulated."— Presentation transcript:
ARP AND RARP ROUTED AND ROUTING Tyler Bish
ARP There are a variety of ways that devices can determine the MAC addresses they need to add to the encapsulated data. Some keep tables that contain all the MAC addresses and IP addresses of other devices that are connected to the same LAN. They are called Address Resolution Protocol (ARP) tables, and they map IP addresses to the corresponding MAC addresses.
ARP TABLE ARP tables are sections of RAM memory, in which the cached memory is maintained automatically on each of the devices. It is a rare occasion when you must make an ARP table entry manually. Each computer on a network maintains its own ARP table. Whenever a network device wants to send data across a network, it uses information provided by its ARP table.
ARP REQUEST If a host wants to send data to another host, it must know the destination IP address. If it is unable to locate a MAC address for the destination in its own ARP table, the host initiates a process called an ARP request. An ARP request enables it to discover the destination MAC address
ARP REPLY Because ARP request packets travel in a broadcast mode, all devices on the local network receive the packets and pass them up to the network layer for further examination. If the IP address of a device matches the destination IP address in the ARP request, that device responds by sending the source its MAC address. This is known as the ARP reply
RARP Reverse Address Resolution Protocol. Protocol in the TCP/IP stack that provides a method for finding IP addresses based on MAC addresses.
RARP REQUEST If a host wants to send data to another host, it must know the destination MAC address. If it is unable to locate a IP address for the destination in its own RARP table, the host initiates a process called an RARP request. An RARP request enables it to discover the destination IP address
Routing Examples of routing protocols include the Routing Information Protocol (RIP), the Interior Gateway Routing Protocol (IGRP), the Enhanced Interior Gateway Routing Protocol (EIGRP),and Open Shortest Path First (OSPF).
Routing Routing protocols enable routers that are connected to create a map, internally, of other routers in the network or on the Internet. This allows routing (i.e. selecting the best path, and switching) to occur. Such maps become part of each router's routing table.
Routable Protocols such as IP, IPX/SPX and AppleTalk provide Layer 3 support and are, therefore, routable. However, there are protocols that do not support Layer 3; these are classed as non-routable protocols. The most common of these non-routable protocols is NetBEUI. NetBEUI is a small, fast, and efficient protocol that is limited to running on one segment.