Network Protocols

©Richard L. Goldman

September 18, 2001

Protocol• A common set of rules that defines how two

devices will communicate with each other.• Protocols Define:

– Syntax• Format of the data• Coding schemes used

– Semantics• Connection and error handling control

– Timing• Speed and sequence

• A Group of protocols that work together is called a protocol suite or protocol stack.

Routable vs. Non-Routable Protocols

• Non-routable protocols– Can only transfer data between devices within a single

LAN.– Use hardware address (MAC)– Operate at the Data Link layer

• Routable protocols– Can transfer data between different LANs– Use logical addresses– Operate at the Network layer

Common LAN Network Protocols

• TCP/IP– Transmission Control Protocol/Internet Protocol

• IPX/SPX– Internetwork Packet Exchange/Sequence Packet Exchange

(Novell)

• NetBIOS– Network Basic Input Output System

• NetBEUI– NetBIOS Enhanced User Interface

• AppleTalk– Apple Macintosh Computers

Transmission Media• Each protocol must use some type of transmission media to

communicate with other devices on the network.• Common Transmission media:

– Category Cable (Cat.1-7)– Coaxial Cable– Fiber optic Cable– Microwave– SSR (Spread Spectrum Radio)– Wi-Fi (Wireless Fidelity) – IEEE 802.11b– PSTN (Public Switched Telephone Network)– DSL (Digital Subscriber Line)– ISDN (Integrated Services Digital Network)– ATM (Asynchronous Transfer Mode)– FDDI (Fiber Distributed Data Interface) - WAN

Local Area Networking Technology

• The LAN network technology controls how the data is electrically transmitted on the particular media of a LAN.

• The protocols for LAN network technology are contained within the ROMs of network devices such as a NIC used in a personal computer.

• Common Networking technology:– Ethernet– Token Ring

Interconnection Protocols• X-ON/X-OFF

– X-ON when ready to receive– X-OFF when not ready to receive– No error detection

• Xmodem– File transfer protocol– Uses Stop-and-Wait ARQ (Automatic Repeat Request)– Half-duplex

• Kermit– File transfer protocol– PC to mainframe (Both PC and mainframe must run Kermit)– Asynchronous– Uses CRC

• X.PC– Converts asynchronous data into packets for X.25 networks

TCP/IPProtocol Suite

TCP/IP

• TCP/IP is a routable protocol.

• Routable protocol alow data to be routed to computers on different networks.

• TCP/IP is the protocol of the Internet and is used by networks that want to directly access to the Internet.

OSI Model

Softw

are

Hardware

7 - Application

6 - Presentation

5- Session

4 - Transport

3 - Network

2 - Data Link

1 - Physical

DoD - ARPAnet

Softw

areHardware

4 Process /Application

3 Host-to-Host

2 Internet

1 Network Access

TCP/IP

Softw

are

Hardware

4 Application

3 Transport

2 Internet

1 Network Access

•TCP/IP is a 4 level protocol that was patterned after the DoD protocol used in the ARPAnet network.

Common TCP/IP Subprotocols and ServicesTCPUDPIPFTPTFTPHTTPPOPSMTPNNTPARPRARPSNMPICMPIGMPTelnetDNSDHCP

Transmission Control ProtocolUser Datagram ProtocolInternet ProtocolFile Transfer ProtocolTrivial File Transfer ProtocolHypertext Transport ProtocolPost Office ProtocolSimple Mail Transfer ProtocolNetwork News Transfer ProtocolAddress Resolution ProtocolReverse Address Resolution ProtocolSimple Network Management ProtocolInternet Control Message ProtocolInternet Group Management ProtocolTerminal EmulationDomain Name SystemDynamic Host Configuration Protocol

• The TCP/IP subprotocols each perform specific functions that can be mapped to the layers of the OSI model

TCP/IP Subprotocols

OSI Model

7 - Application

6 - Presentation

5- Session

4 - Transport

3 - Network

2 - Data Link

1 - Physical

TCP/IP

ApplicationFTP DNSTFTP NNTPSMTP SNMPPOP TelnetHTTP

Transport TCP UDP

Internet IP ARPICMP IGMP

Network Access EthernetPPP SLIP Token RingCat 1-7 Coax DSL etc.

TCP/IP Example #1 – Internet Browser on Ethernet Network

OSI Model

7 - Application

6 - Presentation

5- Session

4 - Transport

3 - Network

2 - Data Link

1 - Physical

TCP/IP

4 Application

3 Transport

2 Internet

1 Network Access

Internet Explorer

HTTP(Port 80)

TCP

IP

Cat-5

Ethernet

TCP/IP Example #2 – E-mail on Ethernet Network

OSI Model

7 - Application

6 - Presentation

5- Session

4 - Transport

3 - Network

2 - Data Link

1 - Physical

TCP/IP

4 Application

3 Transport

2 Internet

1 Network Access

Outlook

SMTP POP (Port 25) (Port 110)

TCP

IP

Cat-5

Ethernet

TCP/IP Example #3 – File Transfer over DSL

OSI Model

7 - Application

6 - Presentation

5- Session

4 - Transport

3 - Network

2 - Data Link

1 - Physical

TCP/IP

4 Application

3 Transport

2 Internet

1 Network Access

Internet Explorer

FTP (Port 20) (Port 21) Data Control

TCP

IP

DSL

PPP

SPX/IPXProtocol Suite

• IPX/SPX is a routable protocol developed by Novell for Netware networks.

• While IPX/SPX is routable, it is not supported by the Internet and can only be used within private networks.

• IPX/SPX uses NetBIOS to perform Session layer functions.

IPX/SPX Subprotocols and Services

SPXIPXSAPNCP

NetBIOSRIP

Sequence Packet ExchangeInternetwork Packet ExchangeService Advertising ProtocolNetware Core Protocol

Network Basic Input Output SystemRouting Information Protocol

IPX/SPX

OSI Model

Softw

are

Hardware

7 - Application

6 - Presentation

5- Session

4 - Transport

3 - Network

2 - Data Link

1 - Physical

IPX/SPX

Softw

are

Hardware

NCPSAPRIP

IPX

NetBIOS

Transmission Protocol & Media

Novell’s IPX/SPX uses NetBIOS to complete its suite of protocols.

SPX

NetBIOS/NetBEUIProtocols

NetBIOS/NetBEUI

NetBIOSNetBEUI

Network Basic Input Output SystemNetBIOS Enhanced User Interface

NetBIOS & NetBEUI

OSI Model

Softw

are

Hardware

7 - Application

6 - Presentation

5- Session

4 - Transport

3 - Network

2 - Data Link

1 - Physical

NetBIOS & NetBEUI

Softw

are

Hardware

Transmission Protocol & Media

NetBEUI

NetBIOS

AppleTalkProtocol Suite

AppleTalk

• Apple’s protocol used to network Apple Macintosh computers Apple printers.

• Very slow and only suited for small networks.• Designed to runs over Apple’s LocalTalk network

(230Kbps).• Versions of AppleTalk are available to run on

other types of networks:– Ethernet (EtherTalk)– Token ring (TokenTalk)– FDDI (FDDITalk).

• Windows NT, Novel NetWare, have services to support AppleTalk.

AppleTalk Subprotocols

AFPASPATPNBPRTMPZIPDDPApple Share

AppleTalk Filing ProtocolAppleTalk Session ProtocolAppletalk Transaction ProtocolName Binding ProtocolRouting Table Maintenance ProtocolZone Information ProtocolDatagram Delivery Protocol

OSI Model

Softw

are

Hardware

7 - Application

6 - Presentation

5- Session

4 - Transport

3 - Network

2 - Data Link

1 - Physical

AppleTalk

Softw

are

Hardware

Apple ShareAFP

ASP

ATP - NBP, RTMP, ZIP

DDP

LocalTalk

Review - PC Networking Protocols

OSI Model

Softw

are

Hardware

7 - Application

6 - Presentation

5- Session

4 - Transport

3 - Network

2 - Data Link

1 - Physical

DoD - ARPAnet

Softw

are

Hardware

4 Process /Application

3 Host-to-Host

2 Internet

1 Network Access

TCP/IP

Softw

are

Hardware

4 Application

3 Transport

2 Internet

1 Network Access

IPX/SPX

Softw

are

Hardware

NCPSAPRIP

IPX

NetBIOS

Transmission Protocol & Media

SPX

NetBIOS & NetBEUI

Softw

are

Hardware

Transmission Protocol & Media

NetBEUI

NetBIOS

AppleTalk

Softw

are

Hardware

Apple ShareAFP

ASP

ATP

DDP

LocalTalk

Mainframe Protocols

Types of Mainframe Protocols

• Mainframe networking uses very different kinds of protocols and are not mapped to the OSI model.

• The three main types of mainframe protocols are:– Character-oriented– Byte-count oriented– Bit-oriented

Character-oriented Protocol• Synchronous block transmission• Half-duplex• Uses 8-bit byte control characters

• ACK +Acknowledgement STX Start of Text• NAK -Acknowledgement SOH Start of Header• ENQ Enquiry ETX End of Text• DLE Data Link Escape ETB End of Transmission

Block• SYN Synchronization EOT End of Transmission

• BSC (BISCYNC)– Binary Synchronous Communications protocol

– Industry standard – IBM

Byte-count Oriented Protocol

• Improvement on BNC

• Add a header to each block with control information

• Eliminates need for ACK

• Eliminates transparency problems

• DDCMP– Digital Data Communication Message Protocol

Bit-oriented Protocols

• Uses a strictly defined frame with each bit in each field containing specific information.

• Supports half-duplex and full-duplex networks

Bit-oriented Protocols - List• SDLC

– Synchronous Data Link Control - IBM

• BDLC– Burroughs Data Link Control

• UDLC– Universal Data Link Control - Sperry

• CDCDLC– Control Data Corporation Data Link Control

• HDLC– High-Level Data Link Control – ISO Standard

• ADCCP– Advanced Data Communication Control Procedure – ANSI Standard

• X.400 and X.500– E-mail message and directory services

• TCP/IP– Transmission Control Protocol/Internet Protocol

• X.25– Packet switching – analog circuits