The document discusses the delivery and forwarding of IP packets, focusing on strategies of direct and indirect delivery. It highlights the role of forwarding to position packets towards their destination using routing tables based on destination addresses and labels. The example provided explains packet forwarding using classful addressing and subnetting within the context of a network routing table.

1. Delivery and Forwarding of
IP Packets
Prof Pranali V Deshmukh
Department
International Institute of Information Technology, I²IT
www.isquareit.edu.in

2. International Institute of Information Technology, I²IT, P-14, Rajiv Gandhi Infotech Park, Hinjawadi Phase 1, Pune - 411 057
Phone - +91 20 22933441/2/3 | Website - www.isquareit.edu.in | Email - info@isquareit.edu.in
•The network layer supervises the handling of the packets by the
underlying physical networks.
•we tend to outline this handling because the delivery of a packet.
•The delivery of a packet to its final destination is accomplished
mistreatment 2 completely different strategies of delivery: direct
and indirect
Delivery

3. Direct Delivery
Direct delivery
Direct delivery

4. Indirect delivery
Link LinkLink
A B
Indirect delivery Indirect delivery

5. Forwarding
• Forwarding suggests that to position the packet in its route to its
destination.
• The net nowadays is created of a mixture of links (networks), forwarding
suggests that to deliver the packet to successive hop (which are often the
ultimate destination or the intermediate connecting device).
• Though the scientific discipline protocol was originally designed as a
connectionless protocol, nowadays the tendency is to use scientific
discipline as a connection-oriented protocol.

6. Topics Discussed
• Forwarding Based on Destination Address
• Forwarding Based on Label

7. Next Hop Method

8. Network Specific
N2 R1
Destination Next Hop
Network-specific
routing table for host S
A
B
C
D
Destination
R1
R1
R1
R1
Next Hop
Host-specific
routing table for host S

9. Host Specific Routing
R2
Host B
R3
Host A
R1
N1
N2 N3
Routing table for host A
R3
R1
R3
......
Destination Next Hop
Host B
N2
N3
......

10. Default Routing
R1
Host A N1
Rest of the Internet
Default
router
R2
N2Routing table for host A
Destination Next Hop
......
N2
Default
......
R1
R2

11. Forwarding in Classfull Addressing

12. Routing Tables for R1 in Given
example

14. Router R1 receives a packet with destination address as
192.16.7.4,the packet will be forwarded as follows:
• The destination address is
• 11000000 00010000 000001110 0001110.
A copy of the address is shifted 28 bits to the right. The result is
• 00000000 00000000 00000000 00001100 or 12.
• The destination network is class C. The network address is extracted by
masking off the leftmost 24 bits of the destination address; the result is
192.16.7.0. The table for Class C is searched. The network address is found
in the first row. The next-hop address 111.15.17.32. and the interface m0
are passed to ARP

15. Forwarding in Classfull Addressing
with Subnetting

16. Thank-You
Prof Pranali deshmukh
Asst. Prof (IT Dept)
8329553976
pranalid@isquareit.edu.in
http://www.isquareit.edu.in/