1. Delivery and Routing of IP PacketsVI
Delivery and
Routing of
IP Packets

2. Delivery Mean  the physical forwarding of packet Concepts :
Connectionless and connection-oriented service
Direct and indirect delivery

3. Connectionless vs Connection-oriented service
Delivery is accomplish using either connectionless or connection-oriented service
Connection-oriented:
Network layer protocol first establish connection
After that, a sequence of packets can be sent one after another.
A packet is logically connected to the packet traveling before it and to a packet traveling after it
When all packet have been delivered, the connection is terminated
Route of a sequence of packet can be made only once, when the connection is established.
Routers do not have to recalculated the route for each individual packet

4. Connectionless
The network protocol treats each packet independently, with each packet having no relationship to any other packet.
Packets may not travel the same path to their destination
IP protocol is a connectionless protocol.
It is designed this way because IP, as an internetwork protocol, may have to deliver the packets through several heterogeneous network
If IP were to be connection-oriented, all of networks in the internet should also be connection-oriented, which is not the case

5. Direct versus Indirect Delivery

6. Figure 6-1

7. Figure 6-2

8. Routing Methods Next- Hop routing Network-specific routing
Host-specific routing
Default routing

9. Figure 4-3

10. Network specific routing
Figure 6-4
Network specific routing

11. Figure 6-5
Host specific routing

12. Figure 6-6
Default routing

13. Static vs Dynamic Routing
Static routing table contains information entered manually
ADM enters the route for each destination in table
When a table is created, it cannot update automatically when there is a change in the internet
Can be used in a small internet or in an experimental internet for troubleshooting
Dynamics routing table
is updated periodically using one of the dynamic routing protocol such a RIP, OSPF, or BGP
Whenever there is a change in the internet, such as shut down of a routers or breaking of a link, the dynamic routing protocols update all of the tables in the routers (and eventually in the host)

14. Figure 6-7

15. Figure 6-8

16. Figure 6-9