Networking concepts and hardwareNetworking concepts and hardware

Basic Communications ModelStandards are needed at all Layers User Layer

Application Layer

Computer (Transport) Layer

Transmission Layer

Subnet Layer

1

2

3

Station A Station B

Transmission of Messages1. Within a Single Subnet, or

2. in Point-to-Point Links Between Subnets

4

1 2

Internet LayerStation A Station B

Routing of MessagesAcross multiple subnets in an internet

1

2

34

InternettingStation A Station B

internet: collection of subnets such that any station on any subnet can communicate with any other station on any other subnet simply by giving the

internet address of the other station.

1

2

34

Layering in Major Architectures

Basic Model

Application

Computer(Transport)

Internet

TCP/IP

Internet

IPX/SPX

Internet

Subnet(OSI)

OSI

Application (7)

Presentation (6)

Session (5)

Transport (4)

Network (3):Internet &

Subnet

Data Link (2)

Application Application

Transport:TCP, etc.

Complex:SPX, etc.

Physical (1)

Subnet(OSI)

Subnet(OSI)

LANs, MANs, & WANs

LAN– Local area network– Single office, building, campus– 10 Mbps to 100 Mbps to the desktop common– 1 Gbps coming

Will carry most traffic, because most traffic is local

PC Networking on a small LAN

Network InterfaceCard (NIC)

In each PC

Each client and server needs a NIC rather than a modem

LANs, MANs, & WANs

WAN– Wide area network– Intercity, international– 9,600 bps to 1 Mbps common to the desktop– Links with higher speed are usually shared

(multiplexed) by several desktops Emerged before LANs, due to high cost of long-

distance telephone charges

Microsoft Layered Network ArchitectureMicrosoft Layered Network Architecture

Network Interface Card

Network Adapter Card Drivers

NDIS Interface Streams

Streams

Transport Protocols

Transport Driver Interface

NetBIOS driver

Redirectors Servers WinSock driver

1. Physical

2. Data Link

3. Network

MAC

LLC

4. Transport

5. Session

6. Presentation

7. Application

Kernel Mode

User Mode

Some basic conceptsSome basic concepts

NDIS Interface: Network Driver Specification Interface, wraps NIC drivers and allow communication with multiple protocols, binds a NIC to a protocol.

Streams: multiple channels allowing broader bandwidth for data transfer, envelop the protocols.

Transport Driver Interface: allows software drivers (server, redirector, etc) to communicate with protocols.

Redirectors: software in WS that redirect network drives, printers requests to network I/O requests.

Servers: software that allows a device to accept requests from other devices.

Standard protocolsStandard protocols

NetBEUI - NetBIOS Extended User Interface, “native” Windows protocol, not routable.

TCP/IP - implemented through WinSock, routable, supports SNMP, DHCP, WINS.

NWLink (IPX/SPX) - used to connect to Novell NetWare, just a protocol, not access.

DLC - Data Link Control, used to connect to IBM mainframes and HP printers directly connected to a network (server).

Data Link Layer

Logical Link Control LayerLogical Link Control Layer

Media Access Control (MAC) LayerMedia Access Control (MAC) Layer

802.310Base-T

802.310Base-T

802.310Base-5

802.310Base-5

802.3Other

PhysicalLayer

802.3Other

PhysicalLayer

802.5Physical

Layer4 Mbps

802.5Physical

Layer4 Mbps

802.5Physical

Layer16 Mbps

802.5Physical

Layer16 Mbps

OtherPhysical

Layer

OtherPhysical

Layer

OSIData Link

Layer(Layer 2)

OSIPhysical

Layer(Layer 1)

OSI Data Link Layer is subdivided into two layers Media access control Logical link control

OSI Data Link Layer is subdivided into two layers Media access control Logical link control

LAN Using Ethernet 10Base-T

RJ-45 jacks10Base-T Hub (Multiport Repeater)

Unshielded Twisted Pair (UTP) Wiring(4-Pair Bundle)

PC

RJ-45Jack

NIC

NetworkInterface

Card

10Base-TUTP Wiring

Bundles:4 Pairs

EIACategory3, 4, or 5

NICs

Network Interface Cards

– Implement Physical Layer– Plug and Electrical Signaling

– Implements the Data Link Layer (data packaging, access control, etc.)

– LLC (802.2)

– MAC (802.3 MAC)

Wiring Unshielded Twisted Pair (UTP)

– Twisted several times per foot to reduce interference, T in 10Base- and Unshielded

– No protection except for plastic coating– Distance limitation: 100 meters (attenuation, distortion, noise and interference,

crosstalk) -- propagation

Categories of UTP Wiring– Category 5: The best. Good for 100 Mbps– Category 3 and 4: lower. May be OK for 100 Mbps

Wiring Plugs: RJ-45 Standard– Similar to home (RJ-11) jacks, but wider

CSMA/CD Media Access Control CD: Collision Detection

– If two stations transmit at once ….– Their signals collide, scrambling one another– Because each sender listens (senses the carrier),

both know that there has been a collision– Both stop and wait a random amount of time.

XCollision

101010 001110

Ethernet 10Base-T LAN with Multiple Hubs

Hub 1

Hub 2 Hub 3

Hub 4

StationA

StationB

StationC

StationD

UTPWire

UTPWire UTP

Wire

UTPWire

UTP Wire

Daisy chain, no Loopsallowed!

Daisy chain, no Loopsallowed!

Maximum distancebetween farthest Stations is

4 Hubs/5 100 meter segments

Switches

Switch

StationA

StationB

StationC

StationD

Connection 1A-C

Connection 1A-C

Connection 2B-D

Connection 2B-D

With a switch, multiple stations may transmit simultaneously: no congestion as traffic grows.

Wireless LAN

BroadcastSignal

TransceiverTransmitting

TransceiverReceiving

ClusterTransceiver

Receiving

Antenna

Hub Controller

Wireless LAN

Wireless LAN with Access PointsWireless LAN with Access Points

WirelessNotebook

NIC

Access Point

IndustryStandard

CoffeeCup

To EthernetSwitch

Antenna(Fan) PC Card

Connector

802.11 Wireless LAN Speeds802.11 Wireless LAN Speeds

802.11 2 Mbps (rare)2.4 GHz band (limited in bandwidth)

802.11b 11 Mbps, 2.4 GHz3 channels/access point

802.11a 54 Mbps, 5 GHz (> bandwidth than 2.4 GHz)

11 channels/access point 802.11g 54 Mbps,

2.4 GHzlimited bandwidth

AddressAddressesesAddressAddresseses

Ethernet address (MAC address ) 48-bit unique addresses hard wired in NICs (280 trillion) 12 hex numbers, e.g. 00-A0-C9-9F-00-07 first three identify company, Intel in the example how to see: IPconfig, or System Information

IP address (number) 32-bit value, not hard coded (4 billion), assigned manually or by

DHCP four dotted quads, each quad a decimal from 0-255,

corresponding to eight bits, e.g. UBMAIL IP address is 198.202.0.25

to convert open Calculator select View, Scientific, decimal and type dotted quad decimal value, then select binary.

InternetinInternetinggInternetinInternetingg

Station A wants to send message to station D, but IP number is not in the same subnet -- no can do!

Sends the message to the default IP router -- default gateway All stations belonging to the same subnet share the first three dotted

quads. 204.52.128.67 and 204.52.128.147 are in the same subnet, while

198.202.0.25 is not.

A,B and C-Class NetworksA,B and C-Class NetworksA,B and C-Class NetworksA,B and C-Class Networks A-class networks

first 8 bits fixed, from 0-126 (only 127) very large companies like IBM, BBN, DEC,HP can assign 3 dotted quads - up to 16 million hosts

B-class networks first 16 bits fixed, first quad 128-191 and second 0-255 (16,384) Medium-sized companies like Microsoft, Exxon can assign 2 dotted quads - up to 65,535 hosts

C-class networks first 24 bits fixed, first quad 192-223, second and third 0-255

(2,097,152) can assign 1 dotted quad - up to 253 hosts, 0 is the subnet address.,

1 default router address, 255 broadcast address.

Sockets and WinSockSockets and WinSockSockets and WinSockSockets and WinSock Sockets are the basic TCP requirement Socket address

IP address of the receiver Port number of the receiving program (80,21,23) Type of port TCP or UDP

WinSock is an adaptation of sockets to the PC it now comes as part of the PC OSs it is an application programming interface

Internet Host NamesInternet Host NamesInternet Host NamesInternet Host Names Host names in Windows

HOSTS - a list of IP and names (each machine) DNS - a server with a common table of IP & names (use with

Windows 2000, together with Active Directory) WINS - Windows Internet Name Server

not DNS compatible (use only with NT/9x) can resolve IP addresses inside a Windows network good with dealing with NetBEUI names

FQDN Fully Qualified Domain Name name of a host like: machine.org.domain, e.g.

ubmail.ubalt.edu, with a DNS assignment to an IP

Setting static IP Setting static IP addressesaddressesSetting static IP Setting static IP addressesaddresses

Open Control Panel and select Network Connections Under LAN or High-Speed Internet select local area

connection, right-click and select properties select Internet Protocol (TCP/IP) and click on properties fill in IP number, Subnet Mask, Default Gateway and DNS

server click OK, close. Use ping to test your setup.