Unicast Versus Multicast Routing
| Unicast Versus Multicast Routing |
| |
 |
| |
An
IP unicast routing protocol (RIP, IGRP, EIGRP, OSPF, and BGP) is used to
determine a path from a sender (source) to a single receiver
(destination). Each router along the path from the source to the destination
must contain a routing table that indicates which interface to use to forward
the packet in order to reach the final destination. This route can either be
learned by a dynamic IP routing protocol, a static route, or a default route. As
the packet is routed through the network, routers inspect the destination IP
address to determine the next hop to the final destination and the source
address is not used in making the routing decision. |
| |
|
| |
Of
fundamental importance to this discussion is the fact that the destination IP
address is a Class A, B, or C unicast address. In Figure 5-1, we have a
simple network with a source (172.16.1.1) that is sending to a destination
(172.16.5.1). It is a simple matter for each router to determine the path to the
destination. Assume that only default and directly connected routes are being
used in routers A, B, and C. When the packet from the source arrives at router
A, the destination address in the IP packet is examined and checked against the
routing table. Router A has four routes, three are directly attached, and one is
a default route that says “send every packet that is not destined for one of my
three directly attached networks out the serial link.” Routers B and C have
similar routing tables. As the packet travels through the network, each router
checks the destination IP address, consults the routing table, and forwards the
packet out the proper interface. | |
314 times read
|
Related news
|
| No matching news for this article |
|
Did you enjoy this article?
(total 0 votes)
|
Sections
Comments (0 posted)
Syndication
