CS457/557 - Computer Networks: Chapter 7 - Local Area Network Operating Systems
Objectives
- Understand compatibility issues involved with implementing local area network operating systems.
- Understand the basics of network operating system functionality.
- Understand the important differences between peer-to-peer and client/server network operating system architectures.
- Understand the emerging role of the client network operating system and the universal client.
- Understand how to analyze functional networking requirements and match those requirements to available technology.
Where Do Network Operating Systems Fit?
LAN Software Archtecture
- Network operating systems [interface between LAN hardware & applications]
- Application software
- client front ends
- server back ends (engines)
- LAN productivity software [e-mail, scheduling software, groupware]
- LAN resource management software [provides access to shared resources]
- Security
- Management software
The Client/Server Technology Architecture and Software Compatibility [Fig. 7-2]
- Vertical software compatibility -
- "How do I know that a particular version of UNIX will work on my computer?"
- "If I do get UNIX installed, how do I know which network operating systems and database management systems will be compatible with UNIX and with each other?"
- Horizontal software compatibility -
- "How do I get a Netware client to interoperate with a Windows NT server?"
- "How do I get an Oracle database server to query a Sybase SQL server?"
- "How do I get my Excel spreasheet graph into my Word document?"
- Often requires middleware
- The Enterprise Network - connects client & server: LANs, internetwork, WANS
- enterprise network management systems [HP's OpenView, IBM's NetView, Sun's SunNet Manager]
Network Operating Systems Archtectures
Zero-Slot LANs
uses serial port connections (~80Kbps) or parallel port connections (~130 Kbps)
ex. LANtastic-Z
File Transfer Software
- Laplink
- Interlnk - comes with DOS 6.22
Printer Sharing Networks
Peer-to-peer LANs [Fig. 7.3]
LANtastic, Personal Netware, WFWG
- Device Sharing
- File and Data Sharing
- Worker-to-Worker Communications
- LAN Administration and Security
- Network Adapter Cards
Fully-Integrated LANs (Client/Server)
UNIX, Netware, NT, Banyan Vines, OS/2
- Complex connectivity and interoperaility
- Fast, reliable performance with large numbers of (100+) users.
- Sophisticated LAN administration and security on a par with that found on minicomputers and mainframes
New/emerging Network Requirements
[Fig. 7-4]
- APPLICATION SERVICES
- DIRECTORY SERVICES
- INTEGRATION/MIGRATION SERVICES
Application Choices
Peer-to-Peer vs. Client/Server
Peer-to-peer requires task switching (time slicing) since computers serve dual roles
Client/Server - computers are typically either client or server
Dedicated servers
- File servers - uses access rights tables and file audit database to control access
- Printer servers - uses print queue to manage print jobs
Client Network Operating System (Windows '95/'98, NT Workstation) Functionality
- Operating system capabilities
- 32-bit operating system
- preemptive multitasking
- protected memory space
- support for symmetrical multiprocessing (SMP) for high-powered client apps
- multithreading
- GUI
- application program support (backward compatibility)
- PnP Features
- Peer-to-peer networking capabilities
- File and Printer Sharing
- Workgroup applications
- Client software for communicating with a variety of different server network operating systems [Fig. 7-12, 7-13, 7-14, 7-15(summary)]
- MAC protocols {NDIS / ODI} that allow a client to communicate with a compatible server
- Network transport protocols that package and transfer messages between clients & servers [TCP/IP & IPX/SPX]
- Network redirectors that trap API calls and process them
- Network Client to Multiple Servers
- Remote Access (Windows NT RAS)
Server Network Operating System Functionality
Changing Role of the Server Network Operating System
file/printer sharing (Netware) ==> application sharing
UNIX, TCP/IP, AND NFS AS A NETWORK OPERATING SYSTEM
- UNIX Architecture (systems programs / systems kernel)
- UNIX Shells (Bourne, C, TC, Korn)
- UNIX File System
- TCP/IP Suite of Protocols
- NFS (Network File System)
- NFS Architecture
- NFS (API portion of programs)
- XDR (external data representation) for formatting data
- RPC (remote procedure call) establishes, maintains & terminates communication session
Comparative Network Operating System Functionality
- Directory Services (Netware 3.x - bindery; Netware 4.1 - NDS; NT - domains directory service)
- Application Services (preemptive multitasking, 32-bit execution, multithreaded application support, program execution in protected memory space)
- File Services (FAT, NTFS, HPFS)
- Networking and Connectivity Services (Network Clients Supported?; Network Protocols Supported?; Remote Access and Gateway Services)
- Management and Administration Servives (Installation, Configuration, and Administration; Integration and Migration; Security)
Software Choices
Operating Systems and Network Operating Systems
Operating System Analysis Questions
- Heritage - Was the OS initially designed for multiuser networks?
- Basic design - Does the OS support multuser, multitasking, multithreading?
- Hardware requirements - CPU? memory, disk requirements?
- Networkability - Which networking features are included with the OS? Which must be added? Approximate cost?
- Interoperability - On what platforms will it run?
- Applications - How available are applications that run on this OS? How easy are applications to develop?
- Ease of use -
- system installation
- system configuration
- system management
- system use
- system monitoring
- system troubleshooting and diagnosis
- Future potential - Is it in the twilight or sunrise of its product cycle? governed by standards?
- DOS - A Single User Heritage (redirector)
- OS/2 - Multitasking from the Start (preemptive multitasking & multitasking threads
- Windows NT - 32 bit client/server multitasking operating system with built-in TCP/IP & SNMP
- UNIX - Multiuser Minicomputer Heritage Shows
- TCP/IP
- NFS
- Scalability (multiplatform)
- symmetric multiprocessing
- Banyan Vines (based on UNIX)
- NETBIOS, Redirector and the SMB(Server Message Block) Server
API(application program interface) - allows requests for services from application programs to be passed on to the networked servers that provide these services
NETBIOS protocol varieties
| NETBIOS Protocol |
Communications NOS |
| RFC 1001/1002 |
TCP/IP |
| TOP(technical office protocol |
OSI |
| NETBEUI |
NT, WFWG |
| NETBIOS/IX |
UNIX |
APIs other than NETBIOS
| API |
NOS |
| APPC(Advanced Program to Program Communication) |
IBM SNA |
| Named pipes |
Microsoft LAN Manager |
| SPX/IPX |
Netware |
| Streams |
AT&T UNIX System V |
| Sockets |
Berkeley UNIX |
| VIPC (VINES Interprocess Communications Protocol) |
Banyan VINES |
Slides
Review Questions: [e-mail your answers (where possible) to summers_wayne@ColumbusState.edu before 4 p.m. on Thurs., Oct. 14, 1998]
pg. 286: #2, 25, 38
