Managing A Network

Managing

• Why?

• Who – Network Manager / Network Administrator

• Credentials– MSCE, CNE

– Sun Certified System Administrator Solaris

– Sun Certified Network Administrator Solaris

Managing

• Systems– Clients, Servers, Network Hubs, Routers,

Remote Access Devices, Printers, etc.– Users– Interfacing with other organizations– Audits, backups– Software updates

Server Managing

• Hardware Issues– CPU Power & Number– Memory– Hard Disks, size, type, storage architecture

• SCSI, IDE

• Striping, Mirroring, Raid

Managing Servers

• Busy disks or printers store information in queues, (memory or disk space)

• Disks use an area know as swap space as if it were memory, when memory gets filled.– Free disk space is critical to good performance

• Fragmentation is another concern

Managing Servers

• Drives need to be defragmented routinely

• Drives need to be scanned for bad sectors as numerous writes and re-writes damage the media.

Managing Servers

• Memory– Memory gets sub-divided into page frames– Programs and information are loaded as needed

• Paging

• Look ahead capability

• Page fault occurs when the machine can’t load the next program piece into memory

– Order more memory

Managing Servers

• Stored data errors– Disks wear out– Maximize redundancy against cost

• Redundancy

• Fault tolerance – back-up mechanisms– Trade offs against budget

Data storage models

• Mirroring ( Shadowing)– Two disk exactly the same.

• Hardware & software mirroring

• One controller – two drives

– Duplexing• Town controllers, two drives

Mirror

Duplex

Data storage models

• Raid– Redundant array of inexpensive (independent)

disks ( Hardware or software)– Involves disk striping– Raid levels 0 thru 5– The RAID appears as one logical disk

• RAID –1 is a disk mirror

Data storage models

• Raid– RAID – 5 has at least three disks

• The more spindles, the smaller the impact on disk space

• Data is written across all the disks, including parity

• If a disk fails, the parity is used to restore the data when a new disk is installed

– See - http://www.acnc.com/04_01_00.html#top

Raid 0

                                                               

         

RAID Level 0 requires a minimum of 2 drives to implement

Raid 0

• Characteristics/AdvantagesRAID 0 implements a striped disk array, the data is broken down into blocks and each block is written to a separate disk drive

• I/O performance is greatly improved by spreading the I/O load across many channels and drives

• Best performance is achieved when data is striped across multiple controllers with only one drive per controller

• DisadvantagesNot a "True" RAID because it is NOT fault-tolerant

• The failure of just one drive will result in all data in an array being lost

• Should never be used in mission critical environments

Raid 0

• Advantages Cont.

• No parity calculation overhead is involved

• Very simple design

• Easy to implement

• Recommended Applications

• Video Production and Editing

• Image Editing

• Pre-Press Applications

• Any application requiring high bandwidth

Copyright © 2000 Advanced Computer & Network Corporation. All Rights Reserved.

                                                               

         

Copyright © 2000 Advanced Computer & Network Corporation. All Rights Reserved.

Raid 5

• Characteristics/AdvantagesHighest Read data transaction rate

• Medium Write data transaction rate

• Low ratio of ECC (Parity) disks to data disks means high efficiency

• Good aggregate transfer rate

• DisadvantagesDisk failure has a medium impact on throughput

• Most complex controller design

• Difficult to rebuild in the event of a disk failure (as compared to RAID level 1)

• Individual block data transfer rate same as single disk

Copyright © 2000 Advanced Computer & Network Corporation. All Rights Reserved.

Raid 5

• Recommended Applications

• File and Application servers

• Database servers

• WWW, E-mail, and News servers

• Intranet servers

• Most versatile RAID level

Tape Drives

• Historically proven to confuse people– too many standards across manufacturers

• Cheaper for mass storage of data

• QIC Standard (Quarter inch Cartridge)– 60 megs / 9 data tracks / 300 ft. of tape– cartridge was too big

Tape Drives

• Second Standard (cassette)• Lead to DC (large cartridge)

– MC (small Cartridge)

• Better the controller / faster the backup• QIC-40

• FAT• 20 Tracks• 68 segments of 29 sectors

Tape Drives

• DAT (Digital Audio Tape)– helical scan technology

• digital formatting• high capacity / reliability

• 8mm– high throughput

• DLT (Digital Linear Tape)– 20 to 40 G compressed @ 1.5 - 3 M/sec

Tape Drives

• TRAVAN (3M)– proprietary, levels TR-1 through TR-4– 400 meg uncompressed TR-1– 800 meg uncompressed TR-2– 1.6G uncompressed TR-3– 4G uncompressed TR-4– All drives feature 2 to 1 compression

Tape Drives

• Which one?– Amount of data– Data throughput required– best for you standard– cost $$$

Tape Drives

• Software Considerations– Unattended backup– Macro Capability - changing options / file

selection– Quick tape-erase– Partial tape-erase– Un-erase– Password Protection

Tape Drives

• http://www.quantum.com/src/whitepapers/wp_reliability.htm

• http://www.quantum.com/src/whitepapers/wp_stp.htm

Backups

• Transferring data from a hard drive to another medium– CD, Tape, Disk

• Full Backup– Image– File – file

Backups

• Incremental– Copy the files that have changed since the last

backup.

• Differential– Files that changed since the last full b/u

• Daily – Copy files that changed on a particular day

Other Storage Devices

• Jazz Drives

• Zip Drives

• LS-120 drive

• Magneto-Optical

• WORM drives

Network Performance

• SNMP- Simple Network Management Protocol– Part of TCP/IP

– Stores information in MIB, management information base

– Collected using software agents

– Monitored by a SNMP management station

• CMIP – Common Management Interface Protocol– Higher memory requirements

– Part of OSI model

• http://www.3com.com/solutions/traffix/demoreq.html

Tools

• Multi Meter– Voltmeter– Ohm Meter

• Cable scanner– Optical Fault Finder– Time domain reflecometer (TDR)

• Protocol Analyzer

Firewalls

• http://www.spirit.com/CSI/firewalls.html

• http://www.firewallguide.com/

• http://www.firewall.com/

• http://firewall.esoft.com/

• http://www.iss.net/customer_care/resource_center/whitepapers/

Firewalls

• Address filtering

• Packet filtering

• Network address translation

• PROXY server

Vulnerabilities

• Personal computer

• Network

• Mainframe

• Files & Programs

Vulnerabilities

• Privacy

• People

• Building

• Equipment

Trends that create vulnerabilities:

• Networking systems are proliferating, radically changing the installed base of computer systems and system applications.

• Computers are an integral part of American Business, computer related risks cannot be separated from general business risks.

Trends

• The widespread use of databases containing personal information, i.e. medical or credit records, places individual privacy at risk.

• Computers are placed in areas that demand a high degree of trust, (i.e. medical instruments) increases the likelihood that accidents can result in death.

The ability to abuse computer systems is widespread.

• The International political environment is unstable, raising questions about the potential for transnational attacks as computer networks are growing.

• Computers are in demand and easily stolen.

Security

• Security implementation depends upon - – Value of the information protected.– Function the system performs– Cost vs. Benefit– Nature of the organization

The Nature of Security

• Vulnerability

• Threat

• Countermeasure

• Security must be holistic -

• Technology, Management, and Social Elements

Consists of -

• Computer hardware, software, network, facilities, and people

• Safety and Security go hand in hand

• Physical Security - protecting the building and the personnel within the building.– Use access control -– Cipher locks, fences, guards, TV monitoring

Consists of -

• Program Security - ensuring that computer programs are not tampered with and the physical code is reliable.

• Use frequent audits, local administrator, configuration control

• Make use of accounting programs

Computer security

• More information is available to more people. the lack of control over information increases the opportunity for harm.

• Technology is advancing at a rate that out paces the legal system.

Authorization vs. Access -

• Ensuring that those that use the programs are in fact authorized to perform the function.

• Password control, access control

• Network Security - monitoring the computer network for unusual occurrences.

• Network management software

Site Security -

• Ensuring that the computer location is protected and that in the event of a disaster the software & hardware are protected.

• Off sight storage of software and files

• Alternate sight if primary sight is damaged

Personnel Security -

• Monitoring the employees within an organization.

• Codes of Conduct, Security clearances,

• Background checks, network software to

• Watch for unusual activity, two-person control