- OSI Layer 3 used for addressing the net - Four processes to ensure communication - Protocols running in layer 3 - IPv4 and its characteristics

1. Network Fundamentals – Network Layer – Layer 3
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Ahmed Hamed Attia Kotb Hussein Teaching Assistant CS Department
By
Ahmed Hamed Attia Kotb
ahmed_hamed@ci.suez.edu.eg
+201227253795
Network Layer – Layer 3

2. Agenda
• Network layer (Layer 3) functionality
• Communication from host to host
• Layer 3 protocols
• IP v4
• Separating hosts into networks
• Hierarchy addressing schema
• Routing
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Ahmed Hamed Attia Kotb Hussein Teaching Assistant CS Department
Network Fundamentals – Network Layer – Layer 3

3. Network layer
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Ahmed Hamed Attia Kotb Hussein Teaching Assistant CS Department
• Divides networks into
groups of hosts to
manage the flow of
data packets within a
network.
• Addressing the net
Network Fundamentals – Network Layer – Layer 3

4. Communication from host to host
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Ahmed Hamed Attia Kotb Hussein Teaching Assistant CS Department
• Four processes:
1. Addressing
2. Encapsulation
3. Routing
4. Decapsulation
Network Fundamentals – Network Layer – Layer 3

5. Network Layer Protocols
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Ahmed Hamed Attia Kotb Hussein Teaching Assistant CS Department
Protocols implemented at the Network layer that carry user data include:
1.Internet Protocol version 4 (IPv4)
2.Internet Protocol version 6 (IPv6)
3.Novell Internetwork Packet Exchange (IPX)
4.AppleTalk
5.Connectionless Network Service (CLNS/DECNet)
Network Fundamentals – Network Layer – Layer 3

6. IPv4 basic characteristics
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Ahmed Hamed Attia Kotb Hussein Teaching Assistant CS Department
• Connectionless - No connection is established before
sending data packets.
Network Fundamentals – Network Layer – Layer 3

7. IPv4 basic characteristics
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Ahmed Hamed Attia Kotb Hussein Teaching Assistant CS Department
• Best Effort (unreliable) - No overhead is used to
guarantee packet delivery.
• Media Independent - Operates independently of the
medium carrying the data.
Network Fundamentals – Network Layer – Layer 3

8. IP header
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• IP Destination Address
• IP Source Address
• Time-to-Live
• Protocol
• Type-of-Service
• MF
• DF
• Version
• IHL
• Packet length
• Header checksum
• Identification
Network Fundamentals – Network Layer – Layer 3

9. Networks – Separating Hosts into groups
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1. Geographic location
2. Purpose
3. Ownership
Network Fundamentals – Network Layer – Layer 3

10. 10
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1. Performance degradation
2. Security issue
3. Address management
Why separate Hosts into network?
Network Fundamentals – Network Layer – Layer 3

11. Thank you
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Ahmed Hamed Attia Kotb Hussein Teaching Assistant CS Department
Network Fundamentals – Network Layer – Layer 3