1. 1 Pertemuan 17 Jaringan LAN (Local Area Network) Matakuliah: H0174/Jaringan Komputer Tahun: 2006 Versi: 1/0

2. 2 Learning Outcomes Pada akhir pertemuan ini, diharapkan mahasiswa akan mampu : Menyediakan LAN

3. 3 Outline Materi Standard IEEE 802 MAC/LLC Hub LAN switch

4. 4 LAN Architecture Topologies Transmission medium Layout Medium access control

5. 5 LAN Topologies

6. 6 Bus and Tree Multipoint medium Transmission propagates throughout medium Heard by all stations –Need to identify target station Each station has unique address Need to regulate transmission –To avoid collisions –To avoid hogging Data in small blocks - frames

7. 7 Star Topology Each station connected directly to central node –Usually via two point to point links Central node can broadcast –Physical star, logical bus –Only one station can transmit at a time Central node can act as frame switch

8. 8 Protocol Architecture Lower layers of OSI model IEEE 802 reference model Physical Logical link control (LLC) Media access control (MAC)

9. 9 Shared Medium Bus and Hub

10. 10 Bus and Hub Bus configuration –All stations share capacity of bus (e.g. 10Mbps) –Only one station transmitting at a time Hub uses star wiring to attach stations to hub –Transmission from any station received by hub and retransmitted on all outgoing lines –Only one station can transmit at a time –Total capacity of LAN is 10 Mbps

11. 11 Two Level Star Topology

12. 12 Hub and Layer 2 Switch

13. 13 Layer 2 Switch Benefits No change to attached devices to convert bus LAN or hub LAN to switched LAN For Ethernet LAN, each device uses Ethernet MAC protocol Device has dedicated capacity equal to original LAN Layer 2 switch scales easily –Additional devices attached to switch by increasing capacity of layer 2

14. 14 Media High performance UTP –Cat 5 and above –High data rate for small number of devices –Switched star topology for large installations Optical fiber –Electromagnetic isolation –High capacity –Small size –High cost of components –High skill needed to install and maintain Prices are coming down as demand and product range increases

15. 15 802 Layers - Logical Link Control Interface to higher levels Flow and error control

16. 16 Logical Link Control Transmission of link level PDUs between two stations Must support multiaccess, shared medium Relieved of some link access details by MAC layer Addressing involves specifying source and destination LLC users –Referred to as service access points (SAP) –Typically higher level protocol

17. 17 Media Access Control Assembly of data into frame with address and error detection fields Disassembly of frame –Address recognition –Error detection Govern access to transmission medium –Not found in traditional layer 2 data link control For the same LLC, several MAC options may be available

18. 18 LAN Protocols in Context

19. 19 Generic MAC Frame Format

20. 20 MAC Frame Format MAC control Destination MAC address Source MAC address LLC –MAC layer receives data from LLC layer CRC –MAC layer detects errors and discards frames LLC optionally retransmits unsuccessful frames

21. 21 Pertemuan 18 Jaringan LAN - Nirkabel Matakuliah: H0174/Jaringan Komputer Tahun: 2006 Versi: 1/0

22. 22 Learning Outcomes Pada akhir pertemuan ini, diharapkan mahasiswa akan mampu : Menyediakan LAN -Nirkabel

23. 23 Outline Materi Ad-Hoc Infra strucutre Standards

24. 24 802.11b Wireless LAN Use multiple frequencies in the 2.4GHz range Utilise Direct Sequence Spread Spectrum (DSSS) technology Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) Wired Equivalent Privacy (WEP)

25. 25 Channel Frequency Frequency range of DSSS is between 2.4 to 2.4835 GHz No. of channels at different part of the world varies (S.E.A. : 13 channels) Each channel bandwidth is approximately 20MHz

26. 26 Channel Frequency 24002410242024302440245024602470248024052415242524352445245524652475 Ch11Ch6Ch1 24002483.5 20MHz

27. 27 Wireless LAN Specifications 802.11b+802.11b802.11g802.11a Data Transfer RateUp to 22MbpsUp to 11MbpsUp to 54Mbps Frequency2.4GHz 5GHz Compatibiliy802.11b802.11g802.11b802.11a only

28. 28 KOMPONEN AKSES Client (PCMCIA card) External Antena Access Points Enterprise Access Point Residential Gateways Access Servers (Public Access) Outdoor Routers (Outdoor)

29. 29 Two Modes in 802.11b Ad-Hoc Mode (also known as “peer-to-peer” mode) Screen Monitor II PC equipped with wireless LAN adapter Notebooks equipped with wireless LAN adapters

30. 30 Infrastructure Mode Screen Monitor II Wired File Server Wired Ethernet Network Gateway to Internet Internet Wired Computer with printer sharing Hardware Access Point Wireless Network PC equipped with wireless LAN adapter Notebooks equipped with wireless LAN adapters Two Modes in 802.11b

31. 31 APLIKASI OUTDOOR Biasanya mempunyai Central Outdoor Unit (Router) dan Remote Oudoor Unit (Router) Tiap segment dapat melayani sampai misalnya 32 remote sites Cakupan sampai to 15 km Kecepatan 11Mbps, 3 channels Mendukung indoor/outdoor connectivity

32. OUTDOOR POINT TO POINT

33. REPEATER POINT TO POINT

34. POINT TO MULTI POINT

35. POINT TO MOBILE POINT