LAN interconnection(LAN Switch)

LAN interconnection and layers

Repeater

Simply regenerates electrical signals. So, all signals are propagated to all LAN

segments. (no filtering) Repeater is called Ethernet hub.

Regenerating signal of repeater

Network configuration using hubs

Ethernet: sharing bandwidth

All devices based on the Ethernet hubs share the whole bandwidth of the link (ex, 10Mbps). That is, a station can transmit with 10Mbps at any moment, but can not always transmit with this rate.

Because of collision

Bridge

A bridge can segregate the whole Ethernet network into several regions, reducing the number of stations to share the same link bandwidth.

In the figure below, instead of 12 stations sharing 10Mbps, segregate into 4 regions, and only 3 stations in each region share 10Mbps.

Bridge (L2 switch) filtering When a bridge receives a frame, it

transmits the frame only to the port where the destination station is connected, looking up the MAC address table..(filtering)

How to make the address table:self-learning Every time a bridge receives a new frame,

it learns the location of new stations.

loop problem When a bridge makes the MAC address

table, a loop can happen. So, Bridge should eliminate any loop, using

the spanning tree algorithm.

Actual network Reconfigured network usingspanning tree

Switched Ethernet

Ethernet switch is the same as the traditional bridge. The Ethernet switch have separate collision domains at each port like a bridge. So, each station at each port can be guaranteed to use the full bandwidth at any time.

Full Duplex Ethernet

Original Ethernet is the half duplex. Full duplex Ethernet doubles the speed of

the half duplex Ethernet.

Router (L3 Switch)

A router determines which port a received frame(packet) should be transmitted based on the IP address.

Compared to LAN switch(bridge), routers can segregate into even bigger regions, and can do much more functions.

LAN backbone

Consists of many LAN segments. LAN backbone topologies

Bus backbone Star backbone Ring backbone

Bus backbone

Star backbone

virtual LAN Compose LAN segments not by physical

link configuration, but by software Single LAN segment consists of the same

broadcast domain.

물리적 선로 연결에 의해서

세개의 그룹 ( 세그먼트 ) 로

구성되어 있다 .

LAN segment configuration by virtual LAN Regardless of physical line configuration

(ie, location of stations), LAN segments can be reconfigured as wanted.

Cat6513 Cat65134G

이학관

제 1 공학관

제 2 공학관

제 3 공학관

학생회관

명현관 기숙사 4 동

Cat4507R

Cat4507R

Cat4507R

Cat4507R

Cat4507R

Alcatel

OS7700

Alcatel

OC5052

OC5022방목기념관

학군단 체육관

선수숙소

Cat2950G

Cat2950G

게스트하우스BR350 BR350

AP1200OS6024

11M

백마관

토목관

도서관

조형센터

함박관

예체능관

행정동

Cat4507R

Cat4507R

Cat4507R

Cat4507R

Cat4507R

Cat4507R

Cat4507R

명덕관

Alcatel

OC5022

NMS

명진당

Gigabit Ethernet (F/O) Gigabit Ethernet (F/C) 100Mbps Fast Ethernet (UTP)Gigabit Ethernet (F/O)범례

외부 DNS

DMZ

라우터 (C7507)

Virus Wall(Rardware)

DACOM 인문캠퍼스

KT

T3(45M)

Metro(100M) Metro(1G) ATM(32M)

IDS( 외부 )

연구망

방화벽 (ASF)

홈페이지 / 메일 /FWMNG

Alteon AD2

종합정보시스템 (Myiweb)

Alteon AD2(SLB)

IDS

자연캠퍼스 네트워크 구성도