1. © 2007 Cisco Systems, Inc. All rights reserved. Valašské Meziříčí 25.4.2015 1 Connecting to the Network

2. Valašské Meziříčí 25.4.2015 2 © 2007 Cisco Systems, Inc. All rights reserved. Objectives  Concept of networking  Benefits of networks  Communication protocols  Local Ethernet network  Access layer devices  Distribution layer devices

3. Valašské Meziříčí 25.4.2015 3 © 2007 Cisco Systems, Inc. All rights reserved. Networking and Its Benefits  Types of networks

4. Valašské Meziříčí 25.4.2015 4 © 2007 Cisco Systems, Inc. All rights reserved. Networking and Its Benefits  Examples of small, medium and large networks

5. Valašské Meziříčí 25.4.2015 5 © 2007 Cisco Systems, Inc. All rights reserved. Networking and Its Benefits  Components of an Information network

6. Valašské Meziříčí 25.4.2015 6 © 2007 Cisco Systems, Inc. All rights reserved. Networking and Its Benefits Roles of computers on a network:  Clients and servers

7. Valašské Meziříčí 25.4.2015 7 © 2007 Cisco Systems, Inc. All rights reserved. Networking and Its Benefits  Computer peer-to-peer network Equal peer nodes function as both "clients" and "servers”.

8. Valašské Meziříčí 25.4.2015 8 © 2007 Cisco Systems, Inc. All rights reserved. Networking and Its Benefits  Computer peer-to-peer network Advantages Easy to set up Simple Low cost

9. Valašské Meziříčí 25.4.2015 9 © 2007 Cisco Systems, Inc. All rights reserved. Networking and Its Benefits  Computer peer-to-peer network Disadvantages Difficult to administer Less secure Not scalable Slow: All devices both clients and servers

10. Valašské Meziříčí 25.4.2015 10 © 2007 Cisco Systems, Inc. All rights reserved. Network Topologies  Logical and physical topologies Physical topology: Where the devices are located. computers hubs switches routers servers

11. Valašské Meziříčí 25.4.2015 11 © 2007 Cisco Systems, Inc. All rights reserved. Network Topologies  Logical and physical topologies Logical topology: How devices communicate with one another. Shows names, addresses, applications.

12. Valašské Meziříčí 25.4.2015 12 © 2007 Cisco Systems, Inc. All rights reserved. Communication Protocols Communication: source, channel, destination

13. Valašské Meziříčí 25.4.2015 13 © 2007 Cisco Systems, Inc. All rights reserved. Communication Protocols  Protocols = Set of Rules When? How long? What box, paper? Sound, Light, Electricity? Uni-, Multi-, Broad-cast? What paragraphs?

14. Valašské Meziříčí 25.4.2015 14 © 2007 Cisco Systems, Inc. All rights reserved. Communication Protocols  Encoding in human communication What is she dreaming about? What has he decoded? Bad encoding - decoding...

15. Valašské Meziříčí 25.4.2015 15 © 2007 Cisco Systems, Inc. All rights reserved. Communication Protocols  Timing and access methods Calling...... sleeping. Bad timing...

16. Valašské Meziříčí 25.4.2015 16 © 2007 Cisco Systems, Inc. All rights reserved. Communication Protocols  Message patterns Unicast Multicast Broadcast

17. Valašské Meziříčí 25.4.2015 17 © 2007 Cisco Systems, Inc. All rights reserved. Communication Protocols Human communications:  messages  unit sizes  timing  encapsulation  encoding  message patterns “Protocol”

18. Valašské Meziříčí 25.4.2015 18 © 2007 Cisco Systems, Inc. All rights reserved. Local Ethernet Network  Devices on a network must share common protocols People must share common languages

19. Valašské Meziříčí 25.4.2015 19 © 2007 Cisco Systems, Inc. All rights reserved. Local Ethernet Network  Standardization in computer communication protocols

20. Valašské Meziříčí 25.4.2015 20 © 2007 Cisco Systems, Inc. All rights reserved. Local Ethernet Network  Physical addressing: MAC addresses

21. Valašské Meziříčí 25.4.2015 21 © 2007 Cisco Systems, Inc. All rights reserved. Local Ethernet Network  Hierarchical design in an Ethernet Network

22. Valašské Meziříčí 25.4.2015 22 © 2007 Cisco Systems, Inc. All rights reserved. Local Ethernet Network  The logical network address: IP address Network address Host addresss Which network? Which host?

23. Valašské Meziříčí 25.4.2015 23 © 2007 Cisco Systems, Inc. All rights reserved. Access Layer Devices  The function of a Hub... but all devices receive all messages. 1 source,...... 1 destination,... Only one communication at a time.

24. Valašské Meziříčí 25.4.2015 24 © 2007 Cisco Systems, Inc. All rights reserved. Access Layer Devices  The function of a Hub 2 sources sending at the same time...... collision !!!

25. Valašské Meziříčí 25.4.2015 25 © 2007 Cisco Systems, Inc. All rights reserved. Access Layer Devices  The function of switches Switch learns MAC addresses and sends messages only to the right destination. Many communications at a time.

26. Valašské Meziříčí 25.4.2015 26 © 2007 Cisco Systems, Inc. All rights reserved. Distribution Layer Devices  The function of routers Packets forwarding Packets filtering Logical grouping of devices Joining – separating networks

27. Valašské Meziříčí 25.4.2015 27 © 2007 Cisco Systems, Inc. All rights reserved. Distribution Layer Devices  Default gateway 192.168.1.1 192.168.1.3 aa.aa.aa.33.33.33 Inside a single network the computers know each other‘s addresses – no problem to communicate.

28. Valašské Meziříčí 25.4.2015 28 © 2007 Cisco Systems, Inc. All rights reserved. Distribution Layer Devices  Default gateway 192.168.1.1 192.168.1.3 aa.aa.aa.33.33.33 But if they want to send a packet outside their own network, they need somebody, who knows the way. They need the Default gateway.

29. Valašské Meziříčí 25.4.2015 29 © 2007 Cisco Systems, Inc. All rights reserved. Summary  Networks carry data.  Hosts can be clients, servers, or both.  All communication needs a source, destination, and channel.  Protocols are sets of rules.  Protocols govern computer communications.  Each network host needs physical MAC address logical IP address.