![SNSCE / IT/ Sem V / S Rijutha / AP / IT
Source to Destination Data
Transfer
⮚Frame from source A reaches destination B.]
⮚VCI change during the trip.
⮚Each switch changes the VCI and route the frame
⮚ Data transfer phrase is active until source sends all its frame](https://image.slidesharecdn.com/cnlec9packetswitching-210626101326/85/CN_Lec-9_Packet_Switching-16-320.jpg)
CN_Lec 9_Packet_Switching
- 1. SNS COLLEGE OF ENGINEERING Kurumbapalayam(Po), Coimbatore – 641 107 Accredited by NAAC-UGC with ‘A’ Grade Approved by AICTE, Recognized by UGC & Affiliated to Anna University, Chennai SNSCE / IT/ Sem V / S Rijutha / AP / IT Department of Information Technology Course Name : CS8591 Computer Networks III Year / V Sem Unit 1: Introduction and Physical Layer Topic 9: Switching II - Packet Switch
- 2. SNSCE / IT/ Sem V / S Rijutha / AP / IT Introduction ➢Connected via many routers ➢Data broken into packets ➢Packet - IP Address and Sequence information
- 3. SNSCE / IT/ Sem V / S Rijutha / AP / IT Introduction ➢Packet travel any path in the network to reach destination ➢Find the fast channel ➢They don't need to arrive in sequence ➢Reassemble at the destination ➢Internet - Packet Switching
- 4. SNSCE / IT/ Sem V / S Rijutha / AP / IT Packet Switching ⮚ Transferring the data to a network in form of packets. ⮚ The data is broken into small pieces of fixed or variable length, called Packet. ⮚ Size determined by the network or the governing protocol. ⮚ Ex: if one of the network's routers fails, packets can be automatically re-routed to avoid that device. Packet Switching
- 5. SNSCE / IT/ Sem V / S Rijutha / AP / IT Packet Switching and its Types ⮚ Principle, Store and Forward ⮚ There is no resource allocation for a packet ⮚ No reserve bandwidth ⮚ No scheduled processing time ⮚ Resource are allocated on demand, FCFS ⮚Other packet being processed, packet wait, delay ➢Types ○ Connectionless (datagram switching) ○ Connection-oriented (virtual circuit switching)
- 6. SNSCE / IT/ Sem V / S Rijutha / AP / IT Datagram Switching ➢Each packet, called a datagram ➢Separate entity ➢Each packet is routed independently through the network ➢Packey may arrive out of order ➢Packey may go missing ➢Datagram switching - network layer
- 7. SNSCE / IT/ Sem V / S Rijutha / AP / IT Datagram Switching A datagram network with four switches (routers)
- 8. SNSCE / IT/ Sem V / S Rijutha / AP / IT Datagram Networks ⮚ It is a connectionless service ⮚ No call setup or teardown phases ⮚ No connection state information in routers ⮚ Packets forward using destination address
- 9. SNSCE / IT/ Sem V / S Rijutha / AP / IT Routing Table Routing Table in Datagram networks ⮚ Routing table dynamic and updated periodically. ⮚ Destination addresses and corresponding forwarding output ports are recorded in the tables ⮚Destination Address, remain same ⮚Switch receive the packet, destination address examined ⮚Routing table, identify the corresponding output port ⮚Better efficiency, resource allocated only when packet is transferred .
- 10. SNSCE / IT/ Sem V / S Rijutha / AP / IT Efficiency and Delay ⮚ Efficiency ○ Better than circuit switching ○ Resource allocated only when packet is transferred ○ Traffic, change the path ⮚Delay ○ High delay than in virtual circuit network ○ No setup and teardown phases ○ Delay is not uniform, packet not travel in same switch
- 11. SNSCE / IT/ Sem V / S Rijutha / AP / IT ⮚Virtual circuit switching is a hybrid technology combining features of both circuit switching and packet switching ⮚Provide connection-oriented service ⮚Setup, Teardown and data transfer phase ⮚Resource allocated, setup phase, circuit switch network, follow same path ⮚Resource allocated on demand, datagram network ⮚Virtual circuit network, data link layer Virtual Circuit Networks
- 12. SNSCE / IT/ Sem V / S Rijutha / AP / IT Virtual Circuit Networks ⮚ Network has switches that allow data from source to destination Virtual CircuitNetwork
- 13. SNSCE / IT/ Sem V / S Rijutha / AP / IT Virtual Circuit Networks ⮚Two Addressing ○ Global ○ Local (VCI) ➢ Global Addressing ○ Network address ○ Used as a common address by all the users of the network ○ A source or a destination needs to have a global address ➢ Local Addressing ○ Virtual circuit Identifier - VCI ○ Used for data transfer ○ A address used by frame between two nodes
- 14. SNSCE / IT/ Sem V / S Rijutha / AP / IT Virtual Circuit Identifier ⮚ Used for data transfer ⮚ Frame arrive switch, it has VCI ⮚Frame leaves, it has different VCI ⮚Delay, for setup and teardown respectively are 1
- 15. SNSCE / IT/ Sem V / S Rijutha / AP / IT Switch and Table ⮚ Frame arrive at port 1, VCI of 14 ⮚Frame leaves from port3, VCI to 22
- 16. SNSCE / IT/ Sem V / S Rijutha / AP / IT Source to Destination Data Transfer ⮚Frame from source A reaches destination B.] ⮚VCI change during the trip. ⮚Each switch changes the VCI and route the frame ⮚ Data transfer phrase is active until source sends all its frame
- 17. SNSCE / IT/ Sem V / S Rijutha / AP / IT Setup Request and Acknowledgement ⮚Setup request in a virtual circuit network ⮚Setup request frame is sent from the source to the destination ⮚ Special frame called the acknowledgment frame ⮚ Completes the entries in the switching tables
- 18. SNSCE / IT/ Sem V / S Rijutha / AP / IT Virtual Circuit vs Datagram
- 19. SNSCE / IT/ Sem V / S Rijutha / AP / IT Puzzle 1. Most packet switches use this principle ____________? a) Stop and wait b) Store and forward c) Store and wait d) Stop and forward 2. In _________ systems, resources are allocated on demand. a) packet switching b) circuit switching c) line switching d) frequency switching 3. A switch in the datagram network uses __________ a) Destination address b) Sender address c) Routing table d) Header
- 20. THANK YOU ! SNSCE / IT/ Sem V / S Rijutha / AP / IT SNSCE / IT/ Sem V / S Rijutha / AP / IT