Overview of Networking and Data Communications

CE 536 - Networking and Microcomputer Systems

Day 6: Network Protocols and Application Programming Interfaces

Network Communications

Redirectors (Client Software)

Application Program Interfaces
File System Drivers

Network Card Drivers

Network Binding Interfaces

Network Transport Protocols

NetBEUI
IPX/SPX
TCP/IP

Protocols Comprising TCP/IP

Domain Name System (DNS)

Internet Documentation

Internet Organizations

Network Communications

Redirectors (Client Software) - map network resources to appear as local resources

Application Program Interfaces - plug-ins to the network operating system which communicate with other programs running on other networked computers
File System Drivers - complies with requests from redirector

Network Card Drivers - interfaces card and operating system

Network Binding Interfaces - binds the network card to transport protocols

Network Transport Protocols

NetBEUI - NetBIOS Extended User Interface

Microsoft transport protocol
Network and Transport layers of OSI model
NetBIOS - programming commands used to manipulate the network

Session layer of OSI model

Cannot be routed beyond local segment

IPX/SPX- Internet Package Exchange/Sequenced Package Exchange

Novell proprietary transport protocol
IPX - handles packet addressing and routing
SPX - handles lost packets and other errors

TCP/IP - Transmission Control Protocol/Internet Protocol

Four Layer Network Architecture
Developed by the Department of Defense in the 1970’s (ARPA - Advanced Research Projects Agency)
Protocols used on the Internet (world-wide collection of interconnected networks)
Network Access and Internet layers communicate with routers
Host to Host layer for reliable communications
Process layer is for actual communications
Internet information is published in documents known as Request for Comments or RFC
Comparing the OSI and TCP/IP Models

Process (Application) Layer - protocols for actual communications

File Transfer - FTP or File Transfer Protocol (STD 9)
Terminal Emulation - TELNET Protocol (STD 8)
Electronic Mail - SMTP or Simple Mail Transfer Protocol (STD 10)
Network Management - SNMP or Simple Network Management Protocol (STD 15)

Host to Host (Transport) Layer - assures reliable communication between hosts since neither the Network Access or Internet protocols are of an end-to-end nature - makes sure data is accurate, in sequence, complete, and free of duplication

TCP or Transmission Control Protocol (STD 7)
Data passed down from higher levels is broken into pieces and given a header with a sequence number
This segment is then passed to the other system which re-assembles the data and verifies the data

Internet (Network) Layer - handles the routing of data

IP or Internet Protocol (STD 5)
Internet addresses are of the form
147.106.xxx.xxx (Allentown College)
147.106.1.5 (Allentown College’s WWW Server)
128.180.xxx.xxx (Lehigh University)

Network Access Layer - controls access to the LAN

Ethernet
Token Ring

Protocols Comprising TCP/IP

A family of over 100 data-communications protocols
TCP - Transmission Control Protocol (STD 7)

Host to Host (Transport) Layer - assures reliable communication between hosts

IP - Internet Protocol (STD 5)

Internet (Network) Layer - handles the routing of data

SMTP - Simple Mail Transfer Protocol (STD 10)

Process (Application) Layer
Electronic Mail

SNMP - Simple Network Management Protocol (STD 15)

Process (Application) Layer
Network Management

FTP - File Transfer Protocol (STD 9)

Process (Application) Layer
File Transfer
ftp hostname

ascii - for ASCII (text) transfers
binary - for binary file transfers
get filename newfilename
retrieve a single file - optional rename
mget filename*
retrieve multiple files - * wildcard
put filename newfilename
send a single file - optional rename
mput filename*
send multiple files - * wildcard
cd, ls -l, dir - remote computer commands
lcd, !ls -l, !dir - local computer commands

TELNET Protocol (STD 8)

Process (Application) Layer
Terminal Emulation
telnet hostname

open hostname
close
quit
VT-100 Terminal Emulation

TN3270 - IBM 3270 Terminal Emulation
RLOGIN

Passes terminal information (e.g. username)
Handles flow control

Domain Name System (DNS) - a hierarchical, distributed method of organizing the name space of the Internet

Fully Qualified Domain Name - a domain name that includes all higher-level domains

	ds1.allencol.edu	ns1.cc.lehigh.edu
Host name:	ds1	ns1
Subnet:		cc
Subdomain:	allencol	lehigh
Top-level Domain:	edu	edu

Top-Level Domains

com, org, net, edu, gov, mil

Country Codes (hundreds…)

ca - Canada
ce - Switzerland
de - Germany
fm - Micronesia
to - Royal Republic of Tonga

Second-Level Domain (e.g., lehigh, allencol)
Domain names correspond to a 32-bit IP address

Five classes of Internet addresses

Class	First Octet	# Networks	Maximum Nodes
A	000-127	127	16.5 Million (255³)
B	128-191	16383	65025 (255x255)
C	192-223	4 Million+	255
D	224-239	Multicasting	(Router updates)
E	240-255	Experimental

Internet addresses are of the form

147.106.xxx.xxx (Allentown College)
147.106.1.5 (Allentown College’s WWW Server)
128.180.xxx.xxx (Lehigh University)

Internet Documentation

RFC - Request for Comments

Descriptions of network protocols or services
Never revised or re-issued with the same number
Always get the most recent RFC on a particular protocol ("Internet Official Protocol Standards" - currently RFC 2200 - STD 1)

FYI - For Your Information

Subset of the RFC series - assigned both an FYI number and an RFC number - if updated, released with a new RFC number but the FYI number stays the same - FYI 4 will always be FYI 4; currently is RFC 1594, was RFC 1325)
Information oriented

STD - Standard

RFCs that document Internet standards
A Standard may be documented with multiple RFCs (e.g., STD 13 Domain Name System - currently documented by RFC 1034 and RFC 1035)
STD number stays the same even if documented by new RFCs

Primary Repositories of Internet Documentation

ftp ds.internic.net (Internet Network Information Center)
ftp nis.nsf.net (National Science Foundation)
ftp ftp.isi.edu (Information Sciences Institute)
ftp ftp.merit.net
ftp nisc.jvnc.net
ftp ftp.concert.net
ftp wuarchive.wustl.edu

Internet Organizations

IAB - Internet Architecture Board - concerned with technical and policy issues involving the Internet architecture
IETF - Internet Engineering Task Force - coordinates the operation, management, and evolution of the Internet
IRTF - Internet Research Task Force - promotes research in networking and the development of new technology
IANA - Internet Assigned Numbers Authority - responsible for assigning numbers to protocol parameters

version numbers
port numbers

Registration Services - Network Solutions, Inc., etc.

Internet Registry
IP address allocation
Domain name registration
Delegates some number assignment authority to regional registries
RIPE - Reseaux IP Europeens
ARIN - American Registry for Internet Numbers - non-profit established to manage the allocation of IP numbers for areas previously managed by InterNIC (www.arin.net)