Session 02 Network Components

greydullNetworking and Communications

Oct 30, 2013 (3 years and 9 months ago)

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1

Session 02

Network Components

2

Technology and Management


What are the technologies that need to
managed?


Challenges of technological progress on
network management

3

Computer Network Technology



Network comprises



Nodes



Links




Topology: How they’re configured



LAN



WAN

4

LAN



Type of LANs



Ethernet



Fast Ethernet



Gigabit Ethernet



Half
-
duplex vs Full
-
duplex



Switched Ethernet



VLAN



Token ring



FDDI



ATM / LANE

5

WAN



Facilities / Media



Wired: Copper, Coaxial, Fiber



Wireless: Terrestrial, Satellite



Mode: Digital, Analog



Services: POTS, ISDN, Broadband

6

Nodes



Hubs



Bridges/Remote bridges



Routers



Gateways



Switches

7

Network Node Components



Hub



Bridge, Remote bridge



Router, Gateway



Switch

Router

Switched

Hub

Bridge

Remote

Bridge

ATM

Switch

Gateway

External

Network

Router

Hub

Workstation

Dial
-
up

Network

External

Network

Hub

Hub

8

Basic Network Nodes

Routing

ATM Switch

ATM

ATM

Bridge

Local LAN

Ethernet

Packets

Filter

Router

Local Network

IP Packets

Filter

Routing

Gateway

X.25

Network

Packets

IP

Network

Packets

Format

change

External LAN

Ethernet

Packets

External Network

IP Packets

9

Basic LAN Topologies



Bus topology



Used in Ethernet LAN family



Common shared medium



Randomized access (CSMA/CD)



Easy to implement



Lower utilization under heavy traffic 30%
-
40%



Single culprit could effect the entire LAN

Ethernet

DTE

DTE

DTE

DTE

DTE

10

Basic LAN Topologies

DTE

DTE

DTE

DTE



Ring Topology



Used in token ring and FDDI



Shared medium



Deterministic access



Master DTE has control



High utilization >90%

11

Star & Hybrid LAN Topologies



Star topology used with bus and ring topology



Hub is “LAN in a box”



What does the electronic LAN inside the box


look like?



Why has hub become so popular?

DTE

DTE

DTE

DTE

DTE

DTE

DTE

DTE

Token Ring Hub

Ethernet Hub

DTE

DTE

DTE

DTE

DTE

DTE

12

WAN Topologies



Mesh topology



Implemented in network layer level



Multiple paths between nodes



Flat topology, Redundancy, Load balancing, Shortest path



Tree topology



Used with Ethernet bridges



Hierarchical



Efficient for small networks and, special purpose networks

N3

N4

N2

N5

N1

Mesh Topology

N6

N1

N2

N3

N6

N5

N4

Tree Topology

13

Transmission Technology

Transmission Technology

Medium

Mode

Wired

Wireless

LAN

WAN

Digital

Analog

LAN



Physical transport media



UTP



Coax



Fiber



Terrestrial wireless



Satellite transmission

Mobile

Satellite

14

Transmission Modes

User 1

User 2

User 3

User 4

User 30

Time

Channel

Bandwidth

Time

Time

Division

Multiplexing

(TDM)


E1 Time Division Multiplexing (TDM) Transmission

channel 2

channel 1

channel 30

Cell Transmission (ATM)

Bandwidth

Time

Cell

Multiplexing

15

LAN Data Rate

Ethernet

10Mbps

FDDI

100 Mbps

Fast Ethernet

100Mbps

ATM

155.52 Mbps

Gigabit E’Net

1 Gbps

ATM

STM
-
n

16

Hubs



Hub is a platform



Function dependent on what is housed



LAN (Bus/Ethernet)



Switched LAN (Ethernet)



Bridge

Hub

Patch Panel

DTE

DTE

DTE

DTE

Wiring Closet

17

Stacked Hubs



Hub ports can be scaled up using stacked hubs



Stacked hub



extend back plane



connected as daisy chain

Hub 2

Hub 1

Backplane

Interconnection

To DTEs

18

Switched Ethernet



Maximum throughput increased ~N/2 in N
-
port hub



Snooping capability lost for management

Switched

hub

DTE

DTE

DTE

DTE

DTE

DTE

DTE

DTE

19

Client/Server Using Switched Hub

Server

Switched hub

Workstation

Workstation

Workstation

10 Mbps

10 Mbps

10 Mbps

100 Mbps

20

Router


Routes packets between nodes of similar network protocols


Routing table used to route packets


DLC and Physical layers could be different under the same
common network layer protocol

Protocol interface

Physical medium A

TP

NP

DP

Phy

TP

NP

DP'

Phy'

Network A

Protocol P

Network B

Protocol P

Router

NP

DP

Phy

NP

DP'

Phy'

Physical medium B

21

Gateway


Gateway is router connecting two networks with dissimilar
network protocols


Gateway does the protocol conversion at the network layer


Protocol converter does the conversion at the application layer

Protocol interface

Physical medium

TP

NP

DP

Phy

TP

NP'

DP'

Phy'

Network A

Protocol P

Network B

Protocol Q

Gateway

DP

Phy

NP'

DP'

Phy'

NP

22

Switched Networks



Switches are embedded in bridges and routers



Switched network used in WAN



Two types of switched networks



Circuit
-
switched



Packet
-
switched



Datagram service



Virtual circuit

B

A

D

C

DTE A

DTE Z

Pkt3

Pkt2

Pkt1

Pkt3

Pkt2

Pkt1

Pkt3

Pkt2

Pkt1


Virtual Circuit Configuration

23

Switched Networks

B

A

D

C

DTE A

DTE Z

Pkt3

Pkt2

Pkt1

Pkt2

Pkt3

Pkt1

Pkt1

Pkt3

Pkt2

Pkt2

Pkt2


Datagram Configuration

24

Broadband Services

SDH WAN

Campus

ATM / LAN

Network

Campus

ATM / LAN

Network

Residential

Customer

Network

Residential

Customer

Network

STM
-
n

STM
-
n

Service

Providers

Gateway

Broadband

Access

Broadband

Access

25


Integrated services: Voice, video, and data


Narrow band ISDN (Integrated Services Digital
Network)



Basic rate:2B + D (B channel 64 kbps and


D channel 16 kbps



Primary rate: 23B + D channels


Broadband Services



ATM



SDH (Synchronous Digital Hierarchy)



Access technologies:



HFC (Hybrid Fiber Coaxial) / Cable modem



ADSL (Asymmetric Digital Subscriber Line)

Broadband Services