Matakuliah
Tahun
Versi
: H0451/Praktikum Jaringan Komputer
: 2006
: 1/0
Pertemuan 02
LAN
1
Learning Outcomes
Pada akhir pertemuan ini, diharapkan mahasiswa
akan mampu :
• Membangun LAN
2
Outline Materi
• Hub
• LAN switch
3
LAN Architecture
•
•
•
•
Topologies
Transmission medium
Layout
Medium access control
4
LAN Topologies
5
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
6
LAN Equipment
• Repeaters/Hubs:
– At Physical layer
– Ethernet can be extended using repeaters
– 10baseT concentrator is a multi port repeater
– amplifies the signal and increase the overall
distance – restores the amplitude of the signal
– restores signal symmetry
– re-timing can be done
– can be used for dissimilar media
– different LANs cannot be converted – no
protocol conversion
7
LAN Equipment
• Bridges/Switches:
– Operates at Data-link layer or MAC layer
– Multiple LANs can be connected
– Can connect similar LANs with dissimilar media
– Can link LANs of different speeds
– Passes Packets to the other segment only if addressed to a
node in that segment
• Builds an address data base dynamically (a table with
port – address combinations) and use this to filter traffic
• Hence collision domains are extended only if required
– Management software could be used to manage the switches
8
Shared Medium Bus and Hub
9
Two Level Star Topology
10
Hub and Layer 2 Switch
11
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
12