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Delivery and Routing of IP Packets

Oleh:Abdul Kholiq,S.Kom

www.abdkejora.wordpress.com

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Delivery

• Mean the physical forwarding of packet• Concepts :

– Connectionless and connection-oriented service– Direct and indirect delivery

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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

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• 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

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Direct versus Indirect Delivery

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Figure 6-1

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Figure 6-2

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Routing Methods• Next- Hop routing• Network-specific routing• Host-specific routing• Default routing

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Figure 4-3

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Figure 6-4

Network specific routing

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Figure 6-5

Host specific routing

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Figure 6-6

Default routing

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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)

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Figure 6-7

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Figure 6-8

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Figure 6-9