In this ppt, we try to cover basic concept of TCP/IP model. Also we have added how to capture IP Packet. Working of OSI Layers. Also try to cover Packet of Ethernet Frame. PDU = Protocol Data Unit. Cover the difference between Packet and Frames in TCP/IP

1. TCP/IPTCP/IP
Copyright By Hacking Feder
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2. • Why we should know this?
• Because we do not use any GUI (Wireshark)
when we are on a remote machine.
• We rely on CLI?
• A thorough and packet/bit -level knowledge
is required for packet / protocol analysis.
ANSWER THE QUESTIONS

3. • TCP/IP is multi-layered.
• Means - one functionality is running at one
layer and another functionality running at
another layer.
INTRODUCTION – TCP/IP

4. • Why this layered architecture?
• Extensible
• We can add new functionality to the layer
without having to re-implement the whole
TCP/IP stack code.
INTRODUCTION – TCP/IP

5. • There are two basic architectures to follow
when talking about layers.
• TCP/IP reference model
• OSI (Open Systems Interconnect) Reference
Model
INTRODUCTION – TCP/IP

6. INTRODUCTION – TCP/IP

7. • A packet originating from the source
computer traverse through the layers from top
layer to bottom.
• Each layer adds its own set of headers to the
packet.
• At the destination, the packets traverse from
bottom layer to the top layer.
HOW IT WORKS?

8. • At each layer, the headers are stripped out of
the packet.
• These header give the destination host all the
information needed to process the packet.
HOW IT WORKS?

9. OSI MODEL
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10. • Sending process passes data to the
application layer.
• The application layer attaches an application
header and then passes the frame to the next
layer (presentation layer) – known as
encapsulation.
LET’S GET SOME MORE DETAILS

11. • The process of adding headers is repeated
from layer to layer until the frame reaches the
data link layer.
• There, in addition to a data-link header, a
data-link trailer is added.
• The data-link trailer contains a checksum and
padding if needed.
LET’S GET SOME MORE DETAILS

12. • Why Checksum?
• For error detection
• Why padding?
• For frame synchronization
LET’S GET SOME MORE DETAILS

13. HEADER PAYLOAD TRAILER

14. A TCP PACKET
DATA DATA
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15. • PDU = Protocol Data Unit
• Information that is delivered as a unit.
• Consists of layer's Header, Trailer and Data
encapsulated.
PDU

16. • Process of taking one Protocol Data Unit
(PDU) and enveloping it within a set of protocol
header and trailer.
ENCAPSULATION & PDU

17. • Each layer may add a Header and a Trailer to
its PDU as it proceeds through the layers.
• The Headers contain information that
specifically addresses layer-to-layer
communication
ENCAPSULATION & PDU

18. • Packet – PDU @ Layer 3 (Network Layer)
• Frame – PDU @ Layer 2 (Data Link)
ENCAPSULATION & PDU

19. PACKETS VS FRAMES
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