Ch04 network
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MẠNG MÁY TÍNH
(COMPUTER NETWORKING)
Nội dung môn học
Chapter 1: Computer Networks and the Internet
Chapter 2: Application Layer
Chapter 3: Transport Layer
Chapter 4: Network Layer
Chapter 5: The Link Layer and Local Area Network
Data Link
Chapter 6: Wireless and Mobile Networks
Chapter 7: Multimedia Networking
Chapter 8: Security in Computer Networks
Chapter 9: Network Management
1.2
Chapter 4: NETWORK
LAYER
Network Layer Design Isues
• Store-and-Forward Packet Switching
• Services Provided to the Transport Layer
• Implementation of Connectionless Service
• Implementation of Connection-Oriented Service
• Comparison of Virtual-Circuit and Datagram Subnets
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1.4
1.5
Store-and-Forward Packet Switching
The environment of the network layer protocols.
fig 5-1
6
1.6
2-key network-layer functions
Forwarding: move pkts from router’s input to appropriate
router’s output
Routing: determine route for pkts from source to dest
Routing
algorithms
1.7
Interplay btw routing and forwarding
1.8
Services Provided to the Transport Layer
The services need to be carefully designed with the following goals
in mind
1.
The services should be independent of the router technology.
2.
The transport layer should be shielded from the number, type,
and topology of the routers present.
3.
The network addresses made available to the transport layer
should use a uniform numbering plan, even across LANs and
WANs.
1.9
Network layer connectionless and
connection-oriented service
Datagram network provides network layer connectionless service
Virtual circuits network provides network layer connection-
oriented service
Similar to the transport layer services, but:
Service: host-to-host (transport communication: process-toprocess)
No choice: network provides one or the other
Implementation: in network core
1.10
Implementation of Connectionless
Service
11
1.11
Implementation of Connection-Oriented
Service
Routing within a virtual-circuit subnet.
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1.12
Comparison of Virtual-Circuit and
Datagram Subnets
5-4
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1.13
Router Architecture Overview
What is inside a router?
Two key router functions:
Run routing algorithms/protocol (RIP, OSPF, BGP)
Forwarding datagrams from incoming to outgoing link
1.14
Input port functions
1.15
Output port functions
1.16
Routing Algorithms
The Optimality Principle
Shortest Path Routing
Flooding
Distance Vector Routing
Link State Routing
Hierarchical Routing
Broadcast Routing
Multicast Routing
Routing for Mobile Hosts
Routing in Ad Hoc Networks
1.17
Routing Algorithm Classification
1.18
A Link-State Routing Protocol
1.19
A Link-State Routing Protocol
Dijsktra’s Algorithm
1.20
A Link-State Routing Protocol
Dijsktra’s Algorithm: example
1.21
A Link-State Routing Protocol
Dijsktra’s Algorithm: example
1.22
A Link-State Routing Protocol
Dijsktra’s Algorithm: discussion
1.23
Distance Vector Algorithm
1.24
Distance Vector Algorithm
Bellman-Ford example
1.25
