Network Management Notes
I Understanding Networks
- Chapter 1 - A Networking Overview
- Chapter 2 - Sharing Computer Resources
- Chapter 3 -Using Electronic Mail
- Chapter 4 - Using File Servers
- Chapter 5 - Using Protocols, Cables and Adapters
- Designing Networks for Las Vegas Schools
- Chapter 6 - Using Workstations
- Chapter 7 - Using NetWare
- Chapter 8 - Using Windows NT
- Chapter 9 - Using Peer LANs
- Chapter 10 - Using UNIX LANs
- Chapter 11 - Using Network Applications
- Chapter 12 - Managing Your Network
LAN - Local Area Network
Understanding What a LAN Can Do
- Share Data
- Share Software Applications Resources
- Share Hardware Resources
- Communicate with Others
Understanding the Components of a LAN
Computers
WorkStations(Clients) & Servers
LAN cables
- Thinnet (thin coaxial wire)
- Thicknet (thick coaxial wire)
- STP (shielded twisted pair)
- UTP (unshielded twisted pair)
- fiber optic
Topology
Network interface cards
Ethernet cards: BNC (T) connector; DB15; RJ-type - 10 Mbit/sec
uses Carrier Sense, Multiple Access/Collision Detection
Token Ring cards: DB9 or RJ-type - 4 - 16 Mbit/sec
uses tokens
ArcNet - 2.5 Mbit/sec
uses tokens
LANtastic (proprietary system) - 2 Mbit/sec
Data Transfer Speeds on a LAN
10 Mbit/sec = 1.2 Mbyte/sec
LAN speed < speed of slowest component
Network Operating System Software
peer-to-peer LAN vs. client-server LAN
protocol - rules for transmitting data across a network
Operating SystemManufacturerAppleTalkAppleLANtastic
inexpensive
DOS-based
peer-to-peerArtisoftNetware, Netware Lite, Personal Netware
largest user base
supports multiple platform clients
scalable
adequate security
Novell
Network File System (NFS) Sun Microsystems
OS/2
LAN Manager
Microsoft
OS/2 LAN Server
programmable
IBM
Windows for WorkGroups;
Windows 95
inexpensive
peer-to-peer
Microsoft Windows NT Advanced Server
found on multiple platforms
32-bit NOS
supports symmetric multiprocessing
offers C2-level security
supports RAID (redundant array of inexpensive disks)
built-in UPS and tape backup software
Microsoft PowerFusion,
PowerLAN
Performance Technology
Vines Banyan
LAN Application Software
multiple license software
net-aware software
Ensuring LAN Security
Problems
Solutions
Protecting Your Data
File Backup
Data Redundancy (RAID)
Mirror
Power Protection
UPS (Universal Power Supply) vs. SPS (Standby Power Supply)
Sharing Disks and Files
Sharing Files without a LAN
Peer-to-Peer Networks
cables & network cards
software
Windows for WorkGroups
LANtastic
Netware Lite / Personal Netware
1. Using your PC as a Workstation and Server (run DOS SHARE.EXE)
2. Allowing Others to Access Your Computer (rebooting when others are connected)
3. Managing Disk Space (may want to partition disk for sharing)
4. Backing Up and Restoring Peer LAN Files
use tape drive
5. Handling Security and Administration on a Peer LAN
Account IDs and Passwords
Assign Permissions
Network Administrator (Supervisor or Manager)
Server-Based LANs
better performance and increased reliability
ex. AppleTalk, OS/2 LAN Server, Novell Netware, Banyan Vines, Microsoft NT
1. Using your PC as a Workstation (not accessible from other clients)
2. Managing Disk Space (net administrator partitions disk for each user)
3. Backing Up and Restoring Files
backup server
Software = Emerald, Mountain Network Solutions, Palindrome
4. Need Faster, Larger Disks
5. Handling Security and Administration Issues (full-time position)
Account IDs and Passwords
Assign Permissions
Sharing Printers
Using Printer Switchboxes
Using Print Servers
Redirecting Printouts
Can use LPT1, LPT2 & LPT3
Using Laser Printers
Speed (LaserJet IIP = 4 ppm; LaserJet IVsi = 17 ppm)
Duty Cycles = period of time printer can operate without stopping
(1 toner cartridge = 6,000 pages; overhaul = 100,000 pages)
Font Cartridges and Downloadable Fonts
Amount of RAM
Using Dot-Matrix Printers
use for preprinted forms, multipart forms and address labels
Practicing Printer-Sharing Etiquette
Sharing CD-ROM Drives
WORM (write-once-read-many) disk drives (good for backup and archiving)
read/write optical drives
juke boxes
hold at least 680 M per disk
CD-ROMs Require Special Drivers
MSCDEX does not work with all LANs
Sharing FAX Machines
Using Modems and LAN Communications
Dialing Out
RS-232 switchbox
Modem pooling
Connecting through a Gateway Computer
Dialing In (requires remote access software)
Carbon Copy; Close-Up; NETremote; pcANYWHERE
NT & 95 have built-in remote-access capability
Novell's Access Server
supports multiple sessions
DCA's Remote LAN Node
easy to install and use but requires special modem
Connecting LANs through Wide Area Networks
router - connects LANs using the same protocol
bridge - connects LANs which may be using different protocols
An E-mail Overview
mechanism for transferring a file of text from one person to one or more others
must be network based (but not necessarily LAN)
Understanding E-mail Components
requires a "post office" component and a user interface component
post office removes address from message and sends document to its destination invisibly
user interface should include an easy-to-use text editor; should be able to append files created
with a wordprocessor
Looking at the Perfect E-mail Package
Most are expensive
should be installed by network administrator
security & file encryption
new mail notification
proprietary vs. open system
UUCP (Unix-to-Unix copy)
SMTP (Simple Mail Transfer Protocol)
add-ons: voice mail; on-line conferencing, bulletin boards
should be able to archive and organize mail, forward & reply to mail with annotations
Using Special Delivery
E-mail bridge - connects two similar E-mail systems
E-mail gateway - translates between different message formats for dissimilar systems
Deciding Whether You Need E-mail
monetary cost; disk space; administrative costs
Using X.400, MHS and Other Standards
X.400
CCITT specification for E-mail interexchange
defines addressing
X.401 - describes basic intersystem service elements
X.411 - defines message-transfer protocols
X.410 - defines mail-handling protocols (OSI for E-mail)
not all implementations support sending binary files and Group 3 faxes
requires a gateway from LAN to an X.25 packet-switching network
addresses require at least a user name / user number / first name & surname for local mail
plus an ADMD (Administrative Management Domain) and a PRMD (Private Mail Domain) e.g.
ADMD:MCIMail, PRMD:HighlandsMail, FN:Wayne, SN:Summers
CCITT has also defines X.500 - a directory assistance system for containting E-mail addresses of
users with accounts in X.400 systems
MHS
Message Handling Service standard created by Action Technologies (Open System)
bundled with Netware
requires a dedicated server
sets up a publicly accessible server directory structure
anyone on the net can create a message (standard MHS packet {ASCII file})
MHS mailbox holds messages before passing them to the e-mail mailbox
Using Address Lists
Using a File Server as a Post Office
Each user should have separate & secure mailbox
Using E-mail Products
Pegasus Mail
freeware for Netware LANs
files placed in a public directory
NewMail program informs user when new mail is received
cc:Mail (from Lotus)
DOS, Windows, OS/2 and MAC versions
uses network file server
easy to use
Microsoft Mail
built-into WFWG; Microsoft Mail & Schedule+ Extensions; Microsoft mail 3.1
requires post office on a file server; MSMAIL.MMF file created on each workstation
Going Beyond Electronic Mail
Groupware
Lotus Notes
Microsoft Schedule+
WP Office
Getting an Overview of File Servers
Learning what a File Server Does
Sharing Disk Space and Files
Prevents File-sharing collisions
Sharing Printer (Maybe controlled by a separate print server)
Understanding the Components of a File Server
dedicated computer (requires speed, fast and large hard disk, lots of RAM)
PC-Based Servers
Superservers (AlphaStation, RS/6000, Pentium Pro System), Minicomputer or
Mainframe (Client/Server environment)
Tape backup and/or optical storage
RAID (Redundant Array of Inexpensive Drives)
UPS
High-Speed NIC
Network Operating System Server Software
Server-based vs. Peer-to-peer
Looking at Criteria for a File Server
fast access to files on the server
high capacity for holding files for multiple users
security
reliablity
(connectibility)
Understanding the Server Hardware
Evaluating Hardware Reliability
CPU and hard disk must be reliable and high quality
should have a regular maintenance schedule
must have UPS to protect electricity supply
Evaluating the File Server Hard Disk
must be large, fast and reliable
evaluating disk speed
recording method (MFM, RLL, ESDI, SCSI)
type and on-board intelligence of the controller
type of hard disk
interleave factor
location of files on the disk
data transfer rate < 180K/sec
average seek time < 6 to 20 milliseconds
evaluating disk capacity
IDE usually limited to 2 (SCSI less limiting)
at least 50M for each user
encourage users to use local hard drives for non-shared applications
don't buy diskless workstations
prevent games on server
set up a "retention period" for files
houseclean regularly
(consider optical drives as an alternative)
evaluating file server CPU
depends on NOS
should be fast
evaluating server RAM
depends on NOS
should be lots and fast
evaluating NIC
should be fast with on-board memory
evaluating server's power supply
should be sufficient
keep fans clean
Understanding the Server Software
provides connectivity
honors requests from workstation
Logging in
on Netware: change to drive letter F: and run LOGIN.EXE
on NT: press CTRL-ALT-DEL and then enter user-id and password
on UNIX: enter user-id and password
once logged in, your profile for that server is set
Mapping Drive (redirection)
on Netware: run MAP.EXE to assign drive letters to shared drives (usually done in login script)
on NT: drive letters assigned automatically
on UNIX: logged into own directory
Accessing and Sharing Files
depends on access control rights usually includes private, group and public access
Accessing the LAN Printer
must redirect one of printer ports (LPT1, LPT2, or LPT3) to the network printer
Netware uses CAPTURE
NT uses PrintManager
spooler receives print jobs as LAN messages and stores them in a temp file and prints the
jobs in the order that they were queued
print jobs should reset printer (font, modes, etc.)
Ensuring Server Security
all users must have unique user-ids and passwords (kept in bindery or registry)
remove guest ids & common passwords
grant access rights to users and groups
Assigning the Network Administrator
supervisor / administrator / super user
* Creating New Users (ID, password, rights, home directory) **remove unused accounts**
* Mapping Drive Letters
* Tracking Disk Space
* Fixing Failed Server
* Changing Server Configuration
Comparing Server-Based LANs and Peer LANs
* Loaning a file to someone
* Sharing a printer
* Managing your files
* Security
Understanding Client/Server Architecture
integration and sharing of one or more applications across a network
Understanding Database Servers
serves up database records to applications on other workstations
Using an Uninterruptible Power Supply (UPS)
contains inverter that turns DC power from batteries into AC for the computer
batteries continuously charged
standby power system (SPS) - transfers from AC to DC during outage
Understanding how the UPS and Server Work Together
NOS monitors UPS via a serial connection
Examining Protocols, Frames, and Communications
adapter(NIC) -sends/receives messages among the LAN components
cable - carries the message
protocol - rules for transmitting messages
frames - message packets
types of frames:
* open communications session with another adapter
* send data
* acknowledge receipt of a data frame
* broadcast a message to other adapters
* close a communications session
SENDER ID |
DEST ID |
FRAME TYPE |
DATA/MESSAGE |
CRC |
basic layout of a frame
Using Frames that Contain Other Frames
DATA / MESSAGE
|
HEADER 1 DATA / MESSAGE TRAILER 1
|
HEADER 1 HEADER 2 DATA / MESSAGE TRAILER 1 TRAILER 2
Frame layers
Using Frames and Files
workstation NOS software (as a TSR) intercepts file I/O operation and converts it into a LAN message and adds its own information to the frame and hands it to the adapter
WORKSTATION FILE SERVER
|
| |
DOS FILE REQUEST LAN FILE REQUEST
| |
REDIRECTED <-------------------------->
FILE REQUESTS
(MESSAGES)
|
|
Using the OSI Model |
Open System Interconnection Model (OSI) developed by the International Standards Organization (ISO) |
Layer 1 (The Physical Link) | - voltages, physical circuitry, timing, wiring, uses EIA-232-D interface standard and V.24 & V.28 standards
|
Layer 2 (The Data Link) | - transmission of charactes and their sequencing
checks for errors in transmission
breaks message into frames
holds data in buffers if devices have different speeds
subdivided into Media Access Control (MAC) and Logical Link Control (LLC) layers
MAC - dekas with network access (token-passing / collision sensing)
LLC - sends / receives user data messages
|
Layer 3 (Network Layer) | - defines message addressing & routing methods
routes communications by most logical path
burstiness problem - gaps in communication
packet switching
Virtual mode - packets are held until all packets are received
Datagram mode - user is responsible for reordering packets
|
Layer 4 (Transport Layer) | - establishes protocols and controls and provides data security controls sequencing of packets (resides in host)
|
Layer 5 (Session Layer) | - sets up resources, coordinates equipment, handles transfer of files, recognizes users; sets priorities; supports creation / termination of sessions
|
Layer 6 (Presentation Layer) | - handles formatting and display of information
|
Layer 7 (Application Layer) | - focuses on end-user needs
|
Using Low-Level Protocols
- IEEE 802.3 (Ethernet) - collision sensing
- IEEE 802.5 (Token Ring) - token passing
- ARCNet - token passing
- Fiber Distributed Data Interface (FDDI) - fast token passing
Using Ethernet
CSMA/CD - Carrier-Sense Multiple-Access / Collision Detection
Data broadcast at 10Mbps usually bus-topology
standard based on research at Xerox Palo Alto Research Center in 1975
802.3 distinguishes between MAC and LLC; true Ethernet doesn't; types and lengths of fields in a frame are also different; published in 1985
Using Ethernet Frames
Preamble Destination Source Type Data CRC
8 6 6 2 46-1500 4
Preamble = 10101010....10101011
Destination - if leftmost bit = 0, use unique address (1rst 3 bytes assigned by Xerox, last assigned locally); if leftmost bit = 1, broadcast
Source - leftmost bit = 0
Type - type of higher level protocol associated with this frame; assigned by Xerox
CRC - cyclic redundancy checksum remainder
Using IEEE 802.3 Frames
Preamble SFD Dest. Source Length Data Pad CRC
7 1 2 or 6 2 or 6 2 0-1500 ? 4
Preamble - all 10101010
Start Frame Delimiter - 10101011
Destination - 10Base5 uses 6-byte addresses; leftmost bit (individual/group bit); if 6-byte address, next bit is universally/locally bit
Source - leftmost bit = 0
Length - length of data
Data - if less than 46 bytes, pad is expanded to total 46 byte minimum
Using Token Ring
workstations and file server connected in "ring" fashion using a MSAU (multistation access unit)
IBM Token Ring operates at 4 or 16 mbps
Using Token Ring Frames
TMS380 chipset developed by IBM & TI implements the IEEE 802.5 standards for the Physical & Data Link layers of the OSI model
The Token
Start Delimiter (1 byte) Access Control (1 byte)
PPP T M RRR End Delimiter (1 byte)
P - priority bits T - token bit M - monitor bit R - reservation bit
The Data Frame
|-----Start Frame Sequence--| |-End Frame Sequence-|
SD AC FC DA SA DATA FCS ED FS
DA - Destination Address SA - Source Address
SD - Start Delimiter AC - Access Control FC - Frame Control
FCS - Frame Check Sequence ED - End Delimiter FS - Frame Status
The Abort Sequence
Start Delimiter (1 byte) End Delimiter (1 byte)
Using the Fiber Distributed Data Interface (FDDI)
100 mbps; similar to IEEE 802.5 (Token Ring)
4 bits of data sent using 5 bits of transmission
The Token
Preamble (8) SD (1) FC (1) ED (1) FS
The FDDI Frame
Preamble SD FC DA SA INFO FCS ED FS
NOS Control of Network Adapters
- ODI - developed by Novell & Apple; uses NET.CFG to configure network drivers
- NDIS - developed by 3COM & Microsoft; uses PROTOCOL.INI to configure drivers
[Media Access Control name or protocol name]
Drivername=
Bindings=
keyword= value
Using Midlevel Protocols(Layers 4-7)
NetBIOS, NetBEUI(NetBIOS Extended User Interface), IPX/SPX, TCP/IP (Transport Layer)
- Initializing communications
- protocol identifies workstation by name and/or number (for file redirection and applications)
- activates point-to-point communications
- type of dialog identified -- datagram (sends frames) or session (connection)
- sending / receiving data
- protocol provides means for sending / receiving data
- determines length of message
- determines status of dialog (in case connection broken)
- terminating communications
Using Datagrams and Sessions
- datagram - message never acknowledged by receiver; each datagram stands on its own
- session - logical connection between two workstations (message guaranteed)
Using NetBIOS
- Name support - each workstation identified by name maintained in a table
- Session support - point-to-point connection established between 2 names
- Datagram support - message sent to a name or group of names
- Adapter/session status - information about NICs and currently active sessions
Using IPX/SPX
- IPX (internetwork packet exchange) - datagram-oriented protocol used for file-redirection (OSI Network Layer) - performs addressing, routing, switching of packets
- Netware uses to send/receive packets from server (requires an acknowledgement)
- SPX (sequenced packet exchange) - session-level, connection-oriented protocol
- establishes connection, then transmits messages (guaranteed received & in order)
- (OSI Transport & Session layers) - sits on top of IPX
Using TCP/IP
- IP (Internet Protocol) - provides datagram communications
- TCP (Transmission Control Protocol) - provides point-to-point session communications
- Telnet, FTP, SMTP lie on top of TCP
- NFS & AIX Access provide for file redirection
GOSIP - Government OSI Profile
Using Named Pipes
pipe - stream of data between two programs (i.e. \PIPE\path\name.ext)
used by OS/2
Using File-Redirection Protocols
Using Server Message Blocks(SMBs)
used by LAN Server & LAN Manager to intercept application's file I/O and pass it to the file server
four categories: session control, file access, print service, messages
Using Netware Core Protocol (NCP)
uses a shell program (NETX.COM)
Using LAN Cables
Using Twisted Pair Cable
UTP & STP
Using Coaxial Cable
thin & thick Ethernet
Using Fiber Optic Cable
Using IBM Cabling System
used in Token Ring networks
- Type 1 data cable - copper-based (2 twisted pairs) shielded
- Type 2 data & telephone cable - (6 twisted pairs)
- Type 3 telephone twisted pair cable - (4 twisted pairs) unshielded
- Type 5 fiber optic cable (2 multimode fibers)
- Type 6 patch panel cable (2 twisted pairs)
- Type 8 undercarpet cable (2 twisted pairs)
- Type 9 low-cost plenum cable (2 twisted pairs)
Using AT&T Premises Distribution System
mainly UTP
Using DECconnect
uses thinnet; satellite closet as an Ethernet backbone with taps
Connecting the Cables
Token-Ring uses multistation access units (MSAU) with 8 ports & Ring-In(RI) and Ring-out(RO)
Ethernet <= five 500-meter segments & <= 4 repeaters
Network Adapter Cable Type Max. Length Min. Length # computers
Ethernet Thin 185 meters 50 cm. 30
Thick(drop) 50 meters 2.5 meters 100
Thick(backbone) 500 meters 2.5 meters
UTP 100 meters 2.5 meters
Token Ring STP 100 meters 2.5 meters 260
UTP 40 meters 2.5 meters 72
Using Network Adapters
8 bit vs. 16 bit vs. 32 bit; ISA, EISA & PCI bus
transmission speed
amount of on-board memory for buffering frames & data
compatibility with various CPU chipsets
bus speedDMA usage
IRQ & I/O port addressing
on-board intelligence
ST connectors for fiber, BNC connectors for coaxial, DB-9 connectors for STP
- data transfer - between RAM and adapter card via DMA, shared memory
- buffering - accesses frame; manages data rate differences between PC & network
- frame formation - chunks data (Ethernet 1.5K; Token Ring 4K) adapter provides/removes frame header and trailer (Physical layer's envelope)
- Cable access - CSMA/CD or token-passing
- parallel / serial conversion
- encoding/decoding - represents 1s & 0s as changes in polarity (Manchester encoding)
- sending/receiving impulses
- Repeaters
- Routers
- Gateways used to connect a LAN to non-LAN networks
- Bridges used to connect 2 or more dissimilar LANs (protocol independent but hardware specific)
Designing Networks for Las Vegas Schools
Techniques for gathering Additonal Information
- Interviewing
- open-ended vs. close-ended questions
- primary vs. secondary questions
- funnel format
- inverted funnel format
- psychology of interviewing
- Customizing Questions by Developing Preinterview Profiles
- Recording and Evaluating the Interview
- Observing
Getting Ready
- Identify and define what is going to be observed
- Estimate the length of time this observation will require
- Secure proper management approval
- Explain to the parties being observed what will be done and why
Conducting the Observation
- analyst should
- become familar with surroundings and components
- periodically note the time
- note what is observed as specifically as possible
- refrain from making qualitative / value-judgement comments
- show proper courtesy and observe safety regulations
- Document and Organize Observation Notes
Concluding Systems Analysis and Communication the Findings
- give feedback to persons interviewed or observed
- verify findings with user personnel
Report (for users, general and system management & steering comm.)
- Reasons and Scope of Systems Analysis
- List of Major Problems Identified
- Complete Statement and Definition of User Requirements
- List of Critical Assumptions
- Recommendations
-
A) Steps in Designing Networks
- Segment the Enterprise (by geography, department, building, floor)
- Create a Model LAN for each segment
- Evaluate the LANs to Determine if they are approriate for each segment
- Interconnect Network Segments (Repeaters, Bridges, Routers, Gateways)
B) Networking Elements
- Transmission media: Twisted Pair, Coaxial cable, fiber optic cable, microwave
- Transmission signals: analog vs. digital
- Transmission modes: simplex, half duplex, full duplex
- Network Topologies (star, bus, ring, mesh, tree)
- Network Interface Cards
- Network Servers
- Network Operating Systems (Novell, WFWG, Banyan Vines)
- Modems
- Protocols - OSI, TCP/IP, SNA
C) Types of Transmission Cables
- Twisted Pair (STP & UTP)
- Coaxial (10Base2 & 10Base5)
- choose best cable for the job
- avoid impedance mismatches
- Fiber
D) Designing LANs
- Token Ring (4-16 Mbps with STP or 100 Mbps with FDDI)
requires MAU (multistation access units)
- Ethernet (CSMA/CD)
Premises Distribution System(PDS) - structured cable design method
- Vertical Backbone Subsystem
- Horizontal Backbone Wiring Subsystem
- Work Location Wiring Subsystem
- Adminstrative Subsystem
- Campus Subsystem
Connecting LANs - (Repeaters, Bridges, Routers, Gateways)
Using DOS-Based Computers
Drive Letters
MAP G:=SYS:\USERS\WAYNE
LASTDRIVE=Z
LAN Printer
need to redirect output to a LAN printer
NETWARE: CAPTURE NT NFF NOTIFY T1=10 NB Q=LASERJET
NET PRINT Displays information about print queues and controls print jobs.
Network Commands and Utilities
(DOS/WINDOWS)
NET CONFIG Displays your current workgroup settings.
NET DIAG Runs the Microsoft Network Diagnostics program to display diagnostic information about your network.
NET HELP Provides information about commands and error messages.
NET INIT Loads protocol and network-adapter drivers without binding them to Protocol Manager.
NET LOGOFF Breaks the connection between your computer and the shared resources to which it is connected.
NET LOGON Identifies you as a member of a workgroup.
NET PASSWORD Changes your logon password.
NET START Starts services.
NET STOP Stops services.
NET TIME Displays the time on or synchronizes your computer's clock with the clock on a Microsoft Windows for Workgroups, Windows NT, Windows 95, or NetWare time server.
NET USE Connects to or disconnects from a shared resource or displays information about connections.
NET VER Displays the type and version number of the workgroup redirector you are using.
NET VIEW Displays a list of computers that share resources or a list of shared resources on a specific computer.
(NETWARE)
CAPTURE/ENDCAP Starts/stops printer redirection
MAP Assigns and redirects drive letters
NCOPY copies files
NPRINT prints files
PCONSOLE manages print queues
SYSCON/FILER/SESSION Manages users, files and sessions
DOS Commands and Utilities
Clients must be using the same version of DOS as the server
Many DOS commands do not work across network
Memory Constraints
network software usually loads on the workstations as TSRs and device drivers which often occupy the lower 640K of RAM
The DOS Path Statement
PATH instruction needs to be extended to include network paths
(max. length = 128)
New Files
NetWare requires IPX.COM, NETX.COM, NET.CFG, and SHELL.CFG
Using Diskless Workstations
Using DOS and Microsoft Windows
Windows 3.1, WFWG, Win95, Win NT
can place shareable files (.DLL, .FON, and program files) on server
.INI need to be on client
PRINTMAN used for printing
SYSTEM.INI needs to be customized for each user
Using OS/2 Computers
most network features built-in
supports multi-tasking
Using Macintosh Computers
System 7 supports peer-to-peer file sharing, Ethernet & Token-ring drivers, Interapplication Communication(DDE & OLE) and Apple event Messaging (client/server).
Network stuff configured in the Macintosh Control Panels (CDEVs)
Using UNIX Workstations
has commands like RLOGIN, RCOPY, RWHO, TELNET, FTP, & SMTP
uses TCP/IP
Sun Microsystem's NFS (Network File Systems) can be used to connect UNIX workstations
founded in 1982
LAN TIMES (March 4, 1996): NetWare = 42%, Unix = 25%, NT = 19%, OS/2 = 14%
Reviewing NetWare Products
- expensive
- complicated to install and administer
- TSRs require 60K of RAM
- requires a dedicated file server
- server administration must be done from a client workstation
Using NetWare Utilities
Some of the important NetWare Commands are:
BINDFIX: Attempts to repair defects in the bindery (Use BINDREST if it doesn't work)
BROADCAST: Displays a message to all users logged in
CAPTURE: sets up network print spooling by redirecting printer output to a shared printer
ex. CAPTURE Q=BRAC-HP
DOWN: Shuts down the file server
ENDCAP: Stops capturing printer output for network printing
EXIT: returns to DOS (must be typed after the system is "DOWNED")
FCONSOLE: Displays information about the file server (Menu)
FILER: Creates and manages directories (Menu)
FLAG: Displays or sets file attributes
LOAD: Loads an NLM (NetWare Loadable Module)
LOGIN: Logs you in to the network
ex. LOGIN myservername/myusername
LOGOUT : Logs you off the network
MAP: Assigns drive letters to network drives
ex. MAP F:=MYSERVER/SYS:
MONITOR: Displays the NetWare console monitor screen
NETADMIN: manages the server (Menu)
NCOPY: Copies files on the network
ex. NCOPY REPORT.TXT F:\CS535\REPORT.TXT
NDIR: lists files in a directory including flags and owner of each file
NPRINT: Prints a file on the Network
ex. NPRINT myfile.txt
PCONSOLE: Controls the network printer (Menu) [used to see what jobs are in the print queue]
PRINTCON: Configures printer jobs (Menu)
PRINTDEF: Defines printer forms and print devices (Menu)
RIGHTS: Displays the ACL rights of the user for the current directory
SECURITY: Checks the system's security for possible leaks
SETPASS: Lets you change your password
SYSCON: Console program (Menu)
USERDEF: Creates user accounts (Menu)
VREPAIR: Repairs damage to a network volume
[NOTE: ESC leaves a NetWare menu utility; F1 displays help]
A login script is a program used to set up the workstation's environment each time it is logged on
Mapping Network Drives
3 types of drives: local drives, network drives, & search drives
Search drives are similar to the DOS PATH facility
ex.
DRIVE A: maps to a local drive
DRIVE C: maps to a local drive
DRIVE F:= SERVER1/SYS: /HOME/WSUMMERS
DRIVE G:=SERVER1/SYS2: /
DRIVE H:=SERVER2/SYS: /APPS
SEARCH1:=Z: [SERVER1/SYS: /PUBLIC]
SEARCH2:=Y: [SERVER1/SYS: /PUBLIC/UTILS]
SEARCH3:=X: [SERVER1/ACCT: /APPS]
Sending Messages to Others
SEND "Meeting at 1:30 today." MAX, KEVIN, SERVER2/ALEXA
Understanding NetWare's Design Objectives
enables users to share files
NAC must include a device driver that implements ODI(Open Datalink Interface)
Server uses a proprietary file system structure (not FAT) which includes file tags
Understanding NetWare Security
requires login with username and passwords
can impose workstation, time and account restrictions
trustee rights for directories and files (ACL)
directory and file attributes
Understanding NetWare Fault Tolerance
incorporates SFT (System Fault Tolerance) Technology: provides disk mirroring and disk duplexing
supports UPS monitoring
offers Transaction Tracking System(TTS) to prevent partial updates
Assigning NetWare Users
Regular network users
Operators - have additional privileges
Managers - can create / manage other users
Network Supervisors
Understanding a NetWare Workstation
software required:
IPX - implements IPX/SPX for PC-to-PC and PC-to-server communications
NETX.COM - shell/redirector that shunts DOS file requests by issuing commands to IPX
3 versions
2.x - entry-level (16-bit)
works on 286+ with licenses for 5, 10, 50 & 100 users
uses VAPs(value-added processes) for extra services
3.x - high-performance (32-bit)
works on 386+ with 20, 100 & 250 users
uses NLMs(NetWare loadable modules) for extra services
including TCP/IP
can use NFS to allow a UNIX workstation to use a NetWare file server
can support Macintosh, OS/2 & OSI clients
4.x - enterprise-wide
works on 486+, UNIX and OS/2 based computers with up to 1000 users
downward compatible
uses VLMs(Virtual Loadable Modules) for extra services
can use Windows or Presentation Manager interfaces
replaces bindery with NDS (NetWare Directory Services)
better performance and security
One of the most significant differences between NetWare 4.1 and earlier versions is the way that it handles the servers' resources. Resources in earlier versions were stored in a bindery. NetWare 4.1 uses NetWare Directory Services (NDS) to handles the resources of all servers on a network. NetWare 4.1 also treats everything on the network including users as objects. The best way to manage the network in NetWare 4.1 is to use the NetWare Administrator facility run a Windows program.
History
1985 - Microsoft & IBM codeveloped OS/2 as a multitasking, threaded network operating system
Microsoft developed LAN Manager as their file server while IBM developed LAN Server
1991 - Microsoft & IBM split up
1993 - Microsoft released Windows NT and Windows NT Advanced Server
OS/2
Both LAN Manager and LAN Server run on top of OS/2
uses High Performance File System (HPFS) instead of FAT
Supports client/server applications (SQL Server, Lotus Notes)
NT Server Capabilities
- Architecture Independence
- runs on Intel processors, RISC-based MIPS and Alpha
- parts of NT that are machine-specific are placed in a small part of NT called the Hardware Abstraction Layer(HAL)
- Multiple Processor Support
- designed to support up to 16 processors (Workstation - 2; Server - 4)
- Multithreaded Multitasking
- preemptive, time-sliced, priority-driven multitasking
- Massive Storage Space
- can support up to 4GB
- Centralized User Profiles
- uses the registry to store a user profile
- uses NT File System(NTFS) instead of FAT but can read FAT & HPFS
Enterprise Networking Features
- Event and Account Logging
- Event Viewer - System, Security, and Applications
- who printed and when, who's logged on, who accessed which files
- Remote Access Services
- Domain and Workgroup-Based Administration Features
- trustee-rights
- security access rights
- Fault Tolerance and RAID Support
- database of domain security resides on domain controller with other servers available as backup domain controllers
- can support multiple network cards on one server
- directory replication for backup servers
- hot fixes (under NTFS) for damaged disk areas
- RAID (Redundant Array of Inexpensive Drives) for combining multiple disk drives into a single virtual disk drive
- Level 0 - disk striping (increases speed)
- Level 1 - disk mirroring (for fault tolerance)
- Level 5 -disk striping with parity
- Relatively Low Price for Server and Client Software
- Server = $600+; Workstation = $300+; Client License = $30+
- NDIS(Network Device Interface Specification) Protocol Support
- similar to Novell's ODI (Open Data-Link Interface)
- NetWare Support (first 5 services only with 3.X or 4.X and bindery emulation)
- IPX/SPX Compatible Transport (NWLINK) - simply a protocol
- Client Server for NetWare (CSNW) - allows users to access NetWare file and print servers and use many NetWare utilities
- Gateway Services for NetWare (GSNW)
- File and Print Services for NetWare (FPNW) [$100] - allows NetWare clients to access an NT server
- Directory Services Manager for NetWare (DSMN) [extra charge] - allows NT to manage NetWare servers
- Open Directory Services Interface (ODSI) - released in NT 4.0 (allows access to NDS)
- NetBIOS, DLC, and TCP/IP Options
- DLC (Data Link Control) = (IEEE 802.2) - used to connect to mainframes and JetDirect cards
- Macintosh Connectivity (uses SFM - Services for Macintosh)
- Interoperability with existing networks including SNA and DECnet networks
- Support for both peer-to-peer and client-server networking
- support for distributed applications
Microsoft Enterprise Concepts
Browsing and Browse Servers
- 1. Static Service Lists
- e.g. NET.CFG file in NetWare 3.X identifies the name of the server
- 2. Periodic Advertising
- e.g. NetWare 3.11's Service Advertising Protocol (SAP)
- 3. Name Servers
- e.g. Domain Name Services
- 4. Browse Services
- e.g. Microsoft uses browse masters (master browsers) - 1 for every 32 PCs
uses workgroups (collection of computers that share resources and share the same browse list) [no dedicated servers]
NOTE: only shared resources will show up on lists by the browser (use $ to hide a shared resource)
Domains (Improved Workgroups)
domain - collection of computers that a browse list but access to shared resources is monitored and authorized by a primary domain controller
- 1. domains have only one password to access resources
- 2. password is user-specific and user-id is assigned by the net administrator
- 3. users are granted rights and permissions
- 4. users can be organized into groups
- Single Domain Model
- Master Domain Model - resources managed by different parts of the organization
- Multiple Master Domain Model - for large (>15,000 users) organizations
- Complete Trust Model - multiple domains of users and resources (decentralized but requires rigorous policies to manage)
Inter-Domain Security: Trust Relationships
used to safely and securely allow authentication and validation services between domains
(Established using "User Manager for Domains")
Windows NT Architecture
- HAL - software component provided by the hardware manufacturer [abstracts the differences between different types of hardware from the higher layers of the OS)
- NT Kernel - controls which threads are run on the system's processor(s) and provides synchronization. Dispatches interrupts and exceptions to the appropriate handler.
- I/O Manager - manages all I/O for the OS. Manages communication between drivers
- Object Manager - provides rules for retaining, naming and securing objects
- Security Reference Monitor - enforces access-validation and audit-generation policy
- Process Manager - manages creation and deletion of processes
- Local Procedure Call Facility - allows applications to pass messages to environment subsystems
- Virtual Memory Manager - hides physical organization of memory from the processes
Executive Services
I/O Object Security Reference Local Procedure Call Virtual Memory Process
Manager Manager Manager Facility Manager Manager
Kernel
Hardware Abstraction Layer (HAL) Kernel
^ ^ ^
| | |
v v v
Hardware
NT Security Model
C2-level
- 1. Discretionary Access Control: owner of a resource controls access to that resource
- 2. Object Re-use Protection: OS protects objects so that they are not reused by other processes [i.e. when a file is deleted, it can not be accessed or undeleted]
- 3. Mandatory Logon:
- 4. Auditing: possible to audit security-related events
NT Server Administration
User Management for Domains
- Create, modify, and delete user accounts in the domain
- Define a user's desktop environment and network connections (including logon hours and location)
- Assign logon scripts to user accounts
- Manage groups and group membership
- Manage trust relationships between different domains
- Manage a domain's security policies
File Manager
- managing directories, files, and disks
- viewing properties and attributes
- connecting to network resources
- sharing drives and directories [controlling access to shares, directories and files)
- set and take ownership
- set permissions
- set audits for file and object access
Managing Print Services
- print server - computer to which the printer is connected
- printing device - physical printer
- printer - logical printer
- queue - group of documents waiting to be printed
NT Workstations don't need printer drivers
everything handled through Print Manager including share, permissions and auditing
Server Manager
- view and track:
- users that currently have sessions on a selected computer
- resources open during each session
- how long a resource has been open by a user
- how long a session has been idle
- current information on open file locks, resources, and printers in use
- control directory shares on remote servers
- add/remove servers from domain
- send messages to users
- receive alerts from system
- configure directory replication
- manage services and schedule events on remote servers
Other Administrative Management Tools
- 1. User Manager - similar to Domain User Manager
- 2. Disk Administrator - create and delete partitions, volume sets, and stripe sets.
- 3. Performance Monitor - graphical tool for measuring the performance of your own computer or other computers on a network. On each computer, you can view the behavior of objects such as processors, memory, cache, threads, and processes.
- 4. Backup - graphical tool for protecting data from accidental loss or hardware and media failures. It makes it easy for you to use a tape drive to back up and restore your important files on either the NTFS, FAT, or HPFS file system.
- 5. Event Viewer - monitor system, security, and application events in your system.
- 6. Windows NT Diagnostics - provides information about: OS Version, Hardware, Memory, Drivers, Services, Drives, Devices, IRQ/Port Status, DMA/Memory, Environment, and the Network
Advantages
- No dedicated server
- inexpensive
Disadvantages
- slower performance
- become reliant on others' workstations
- less organized
Using Windows for Workgroups
Microsoft Windows 3.1 + networking + e-mail + Schedule+
easy migration & installation
uses NetBEUI
uses File Manager to share files
uses Print Manager to share printers
can be used as clients within Netware & NT networks
requirements:at least i386 with at least 4M(preferably 8M) RAM, DOS 3.3 & >25M harddisk
how to:
- Sharing Files (options - Read-Only, Full, Depends on Password)
- Sharing Printers (options)
- Connect to Other Computers
Problems:
- 1) keeps passwords after connection
- 2) Gateways with 4X CD-ROM
- 3) memory required for storing connection table
- 4) where is the host table kept?
Additional Features
Microsoft Mail
Chat
Schedule+
WinMeter
NetWatcher
Using Personal Netware and Netware Lite
- cheap - $99 / workstation
- used in networks of 2-25 computers
- uses Novell's ODI (Open Datalink Interface) standard & IPX
- works with other versions of Netware by running NETx.COM
- requires STARTNET.BAT file and a NET LOGIN
- uses many of the standard Netware commands: MAP, CAPTURE, etc.
- maintains audit & error logs
Using LANtastic
- was leader of peer-to-peer networking
- can connect with Macintoshes and Windows machines
- later versions interface with Netware & Windows
- newest version includes networkwide faxing
- later versions require either LANtastic Ethernet cards or special drivers
- sits on top of DOS so is not efficient for large systems
- has own command structure
- includes e-mail & CHAT features
- needs 34K of RAM which can be all upper memory
- easy to use & administer
Using POWERLan
- fast peer-to-peer networking
- can connect to UNIX, Windows & Netware
- comprised of mostly TSRs using disk-caching
Defining UNIX, the Operating System
- available on PCs (LINUX, SCO UNIX)
- available on RISC-based machines, Workstations (Sun & SGI)
- available on mini, mainframes and supercomputers
general purpose operating system (supports multi-tasking and multi-user)
uses TCP/IP for networking
Unix can be used as a DOS file server (NFS - Network File System)
Defining the Characteristics of Unix
- developed in 1969 at Bell Labs by Thompson and Ritchie
- rewritten in C in 1973
- destributed to universities in 70s and 80s
- evolved into System V (1983) from AT&T
- BSD (Berkeley Software Distribution) 1980 supports OSI
contains a kernel - core of the Unix OS which contains service routines that create and manage processes, access and manipulate the file system
shell - Unix command processor - Bourne (sh), C (csh), and Korn (ksh)
Defining the Unix File System
- ordinary files, special files (points of interface to the hardware), and directories
- file names are case-sensitive
- each file has a set of permissions
- can use wildcards ? and *
Defining Communications and Unix
by modem or direct connection
Defining Unix-based Networks
- natural environmnet for client/server computing (ex. Internet)
- clients can be PCs running, DOS, OS/2, Windows, UNIX or Macs
- need to login with username and password (case-sensitive)
Essential Unix Commands
- # - erase character @ - kill character
- exit (CTRL-d) - logs out
- passwd - changes the password
- pwd - prints working direcory (current path)
- ls - list contents of a directory (ls -l = long listing; ls -a = list all files)
- cd - change directory mkdir - make a directory
- rmdir - remove a directory
- cat - concatenate (types contents of) file
- pg - page filter (types contents page at a time)
- who - who is on the system ps - process status report
- cal - displays a calendar cp - copy srcfile to destfile
- mv - move srcfile to destfile rm - removes file(s)
- lp - dubmit print job to print spooler
- set - displays the value of shell variables (used in account configuration)
- path= - establishes path to be used by shell for file searching
- stty - used to read and modify the terminal driver's internal settings and control character settings
- chmod - changes the access mode for files (ex. chmod 755 myfile.c)
- I/O redirection = > <
- pipelines - |
- mail - send / receive mail (alternatives if installed are elm and pine)
- vi - editor (alternative is pico)
- man - manual (online documentation)
- uucp (unix to unix copy) - copies files from one Unix system to another
- uux (unix to unix execute) - lets you work with files on different Unix machines
- uulog - prints a summary log of uucp and uux transactions
Using TCP/IP
- designed for ARPANET
- IP - provides datagram communications between nodes on a network (routes packets)
- SLIP - implementation of IP for serial communications (only asynchronous comm, requires dedicated line, no error detection)
- PPP (Point-to-Point)
- TCP - provides point-to-point guaranteed-delivery communications between nodes
- UDP (User Datagram Protocol) faster but no guaranteed delivery
- ICMP (Internet Control Message Protocol) - enables exchange of control & error messages
- requires Internet address (ARP - Address Recognition Protocol & RARP)
- 4 1-bytes fields divided into 2 addresses - network and host
- uses domain naming
- names listed in /etc/hosts
TCP/IP utilities
- FTP - file transfer protocol (anonymous ftp)
- Telnet - remote connection
- SMTP - simple mail transfer protocol
- rlogin - remote log in
- rcp - remote copy
- rsh - remote shell executes a command at a remote host
- ping - sends an ICMP ECHO-REQUEST to another host or gateway
- traceroute - shows roundtrip time of each message to each hop
- Kerberos - encryption system that validates passwords
- SNMP (Simple Network Management Protocol) - [uses UDP] enables a system to examine and alter networking info maintained by other machines on a network (uses agents to receive information about a device and uses managers to communicate across a network)
Using Network File System (NFS)
- developed by Sun Microsystems
- Application layer that uses TCP/IP
- provides client/server capabilities
Using Remote Procedure Calls (RPC)
enables software on different computers to inter-communicate
NFS uses RPC to redirect file I/O operations
RPC and Client/Server Architecture
each program module written in C
each module designated as a server (backend app. like calculations, report generation, and database storage) or client (user-interface)
programmer creates an RPC compiler script for each module which generates the C source code that "glues" the modules together
NFS uses XDR(External Data Representation) protocol to translate message packets for different types of computers
also uses UDP to send/receive file requests and responses
Using Yellow Pages (alternative to /etc/hosts)
YP - provides a distributed network lookup service
stores databases(maps) of information about users, groups, network addresses, gateways,
uses ypinit to build the Yellow Pages server maps
YP used to resolve naming and address differences
sometimes referred to as NIS (Network Information Services)
Application NFS, MOUNT, YP, YPBIND, NLM, REX
Presentation XDR
Session RPC
Other Unix Software for DOS
- PC Interface - AADU (AIX Access for DOS Users)
- POWERFusion & POWERServe
Systems Management in Unix
- 1) maintain user accounts: ordinary users, priviliged users (root, bin, su), restricted users
- access permissions (RWE, WGO)
- /etc/passwd & /etc/group files
- add a new user: enter in above files, create home directory, create mailbox
- delete old accounts
- 2) maintain the Unix file system
- /etc/update - updates disk data every 30 sec.
- mount & unmount directories (during boot-up and shutdown)
- mount - reports which file systems are currently mounted
- df - displays the number of free disk blocks
- du - reports the name and number of blocks in use for each file system
- quot - reports # of blocks owned by each user
- 3) performs backup
- cp - copies individual files
- tar (tape archiver) - makes and restores copies of files preserving the directory structure
- dump - copies entire file system (restor used to restore file system)
- 4) startup and shutdown the system (must be executed by root from the system console)
- /etc/shutdown
- should use wall (write to all) to warn all users before shutdown
- 5) maintain network
- netstat - provides information about network
- -i interface stats;
- -d data buffers stats
- -r & -rs routing tables information
- -s protocol stats
- nslookup - uses DNS to lookup IP addresses
- arp - views/updates ARP tables
- finger - views list of users logged on the network
- ifconfig - views/configures network interface parameters
- nfsstat - views stats on NFS usage and configuration
- ruptime - displays total time a system has been functioning and its current load
- ypcat - displays contents of NIS database
IV Expanding a Network
Defining Single-User and Multiuser Operating Systems
DOS - single-user
- requires add-ons for file-sharing
- can start network without going into WFWG using NET.
- WFWG, Win 95 provide networking add-ons to DOS
- Novell adds networking instructions to DOS, i.e. NCOPY
- all require modifications to be made to CONFIG.SYS and AUTOEXEC.BAT
- often have problems with the DOS 640K limit
- to share files, requires running SHARE.EXE
- Assigning Rights and Permissions
- Read, Write, Search, Execute, Delete
Encountering Deadlocks
Defining Characteristics of a MultiUser Application
- LAN-aware software should support several application users at the same time
- should support file sharing and record locking
- should allow users to customize their interface
- should allow multiuser printing
Learning How Software Behaves Differently on a LAN
- uses user ID from the logon for the application software and to set up the configuration for the user
- some applications expect to write information to the root (or some to the temp) directories
- need to insure that the user has the appropriate path
- Novell allows map root
Using File Sharing and Record Locking
Using Multiuser Printing
Buying Software Licenses for Multiple Users
- Software for each user
- Network Packs
- Site Licenses
- Copy Protection on a LAN
Science or Art?
Learning the Basics of Network Management
- multi-platform
- multi-vendor
- LAN Management System
need a network plan
- cable diagrams
- cable layout
- network capacity
- protocol and equipment standards
- workstation growth
- new LAN technologies
Examining Technical Issues
most LAN activity (performance stats, traffic volumes, error counts, & accounting info) can be monitored through the NOS (i.e. NT's Performance Monitor, et.al.)
- Dealing with Common Mode Failures
errors by the NIC (use cross-checks and consistency checks)
- Managing Traffic
bottlenecks often caused by hardware/software failures
- Determining Robustness
how does the system handle invalid message packets?
- Testing the LAN
how, when & where do you test?
- Extending the LAN
Examining Administrative Issues
- Managing Software Distribution
- prevent unlicensed copies & viruses
- ensure that everyone is using the same version
- Helping the Administrator
- LAN management software should report results to the Net. Admin.
- Discovering Problems
- software should report bad cables, NICs and other net components
- should monitor servers and gateways
- Logging and Reporting Events
- peak network utilization times
- error conditions
- Determining Operator Control
- should be able to query the status of devices on the net
- should be able to test the status of paths between two points
- Managing the LAN's Configuration
- need to monitor the configuration of workstations including the software that is installed
Managing Access Control and Security
advantages of diskless workstations
Defining the Network Administrator's Role
- must understand the network's configuration, performance, accounting, planning, security, and applications
- must have a collection of tools for doing this
Using the LAN Management Protocols: SNMP and CMIP
- SNMP (Simple Network Management Protocol) outgrowth of TCP/IP (mainly for Internet)
- CMIP (Common Management Information Protocol) part of the OSI standard
Comparing CMIP and SNMP
- both bring network management details to the net admin.
- both help the admin. diagnose problems, plan capacity and generate reports
- both use MIB (Management Information Base) - set of controls supported by devices on the network
Contrasting CMIP with SNMP
Data Access
- SNMP better at retrieving individual items of information while CMIP retrieves collections of information
- SNMP is more focused while CMIP deals with classes of data that must be constrained
Polling versus Reporting
- SNMP works by polling (central management processor asks each device for its current status)
- CMIP uses reporting where the device reports if a change has been made (failed devices can't report)
Size and Performance
- SNMP can be implemented as a DOS TSR
- CMIP is more robust and needs more resources
Transport Layer Protocols
- SNMP uses datagrams via IPX or IP and UDP
- CMIP uses connection-oriented sessions Protocol Standards
- CMIP - uses OSI International Standard
- SNMP - uses TCP/IP which is controlled by the Internet Activities Board
Assessing CMIP and SNMP Product Availability
SNMP is more popular ( more devices support it)
Choosing SNMP or CMIP for your LAN
- SNMP better for LANs
- CMIP better for WANs
Using General LAN Management Tools
- average network is down about twice a month
- average downtime is 1/2 day
Setting Network Management Goals
- 1. Reduce the number of network problems
- 2. Minimize inconvenience and localize the damage
ISO Standards
Category |
Description |
Accounting management |
Records and reports network resource utiliziation data |
Configuration management |
Understands and controls the parameters that define the state of the network |
Fault management |
Detects, isolates, and controls problems on the network |
Performance management |
Analyzes and controls the rate at which the network can process data |
Security management |
Controls access to network resources |
Types of network management tools
- physical-layer tools
- network monitors
- network analyzers
- integrated network management systems
physical-layer tools
- Time-Domain Reflectometer (cable tester)
Can tell length of cable, internal wiring, short circuits, broken wires, crosstalk
- LANMeter & FrameScope (can test into layers 2-4) $4000-$6000
- attach to live LAN to accumulate and display statistics on health & performance of the network
- show frame counts including types of frames
- can reveal excess collisions, late collisions, error frame counts
- don't decode & display frames (only counts types of frames)
- before connecting tool to LAN, you must know type of cable in order to determine the NVP (nominal velocity of propagation) & must calibrate the tester
- you also must know the topology of the network
- should test all cable installations
Cable Management System
database of information about the physical layout of the network
network monitors
- hardware / software device that attaches to a network and monitors the network traffic
- examines frame-level info & compiles stats on utilization, packet type, packets sent & received and packet errors
- costs between several hundred up to $10,000
network analyzers (protocol analyzers)
- used to track-down and fix network problems
- does real-time analysis of packets (capturing and decoding)
- may include test suites
- can filter different types of frames
- can inject extra traffic to simulate additional nodes
- can show which network adapter is mal-functioning
- costs between $10,000 and $30,000
- ex. Network General Sniffer; Hewlett-Packard Network Advisor (includes Fault Finder Expert System); Novell LANalyzer
integrated network management systems
- can monitor entire network from one location
- addresses all five ISO network management categories
- most expensive
Using the Tools
1. Know What is Normal (baselining)
- What is the average network utilization? How does it vary during the day?
- What are the primary applications on the network?
- What protocols are running on the network? What are the performance characteristics of these protocols?
- Who manufactured the NICs, MAUs, hubs, repeaters, bridges, routers, gateways and other devices? What versions of software & firmware are they running? What are their performance characteristics?
2. Observe the Symptoms
- Does the problem affect everyone, everyone in a given area, or random individuals?
- What percentage of time does the problem occur? Is the problem continuous or intermittent? Does it occur regularly?
- What has changed recently? Has a computer device been added to the network? Have any internetworking devices been reconfigured?
- Which vendor's products may have failed to produce these symptoms? What are the vendor and version numbers of the computer systems, NICs, hubs, routers, bridges, application software and NOS software?
3. Make a List of Possible Causes
- must know how each network component can fail and what failure can do to the network
- need to know how each component interacts with other components
- need to understand different protocols and network software and their roles
4. Isolate the Cause and Analyze the Results
Dealing with Common Problems
Where do most network problems occur?
Practicing Performance Tuning
use tools to analyze network-utilization and to identify heavy users and bottlenecks