Understanding the network.pdf - Back to Home

destination address, so it will send the IP datagram on to that host. This forwarding
process is performed over and over until the datagram is delivered to an
intermediate that can actually forward the IP datagram to its destination.
IP Datagram Delivery Models
When any host/end-station sends an IP datagram, the routing process first decides
whether the destination host is on the same local IP network and then determines
how the IP datagram will be forwarded. There are two forwarding models used (as
shown in Figure 2.8):
Figure 2.8. Local and remote delivery models.
• Local Delivery
• Remote Delivery
Local delivery occurs when host-to-host datagram forwarding occurs on the same
physical or logical IP subnet. Remote delivery occurs when the destination and
source hosts are not local to one another and the datagram must be delivered by
way of an intermediate router.
Figure 2.8 illustrates this process rather simply. If host 192.168.7.66 wants to
deliver a datagram to host 192.168.7.23, the local delivery model is usedbecause
the hosts are local to one another. If host 192.168.7.23 wants to deliver a datagram
to host 192.168.8.3, the remote delivery model is used.
NOTE