Media and Medium

Jason Smith

April 21, 2023

Transmission Media

• Coaxial Cable

• Twisted Pair Copper Cable

• Fiber-optic Cable

• Wireless

Coaxial Cable

• Two types– ThinNet (10Base2)

• 10 Mbps, 30 nodes per segment, max 180 meters• LAN

– ThickNet (10Base5)• 10 Mbps, 100 nodes per segment, max 500 meters• Backbone

• Insecure– Coax is easy to splice

Twisted Pair Copper Cable

• Copper wire

• Twist reduces EMI

• Classified by transmission rates– Cat3, Cat5, Cat5e, Cat6

Fiber-Optic Cable

• Glass core with plastic shielding

• Small, light, fragile, and expensive

• Very fast transmission rate

• Can transmit data very far

• Immune to interference

• Hard to splice

Wireless

• Microwave, radio and infrared

Security Concerns

• Easy to insert a node or splice into network

• Most attacks involve eavesdropping or sniffing

• Physical security

• War driving

Storage Media

• Magnetic Storage

• Optical Media

• Solid-State Storage Media

Magnetic Storage

• Floppy Disks– 8”, 5.25”– 3.5”

• Double Density – 800KB• High Density – 1.4MB

• Zip Disks– 100MB, 250MB, 750MB

• Other Disks– Jazz, Pocket Zip, Super Disk,

Tape Backup

Magnetic Storage – Hard Drives

• Around $1/GB• Three interfaces

– SCSI• Introduced in early

1980’s• Very fast, reliable,

expensive• Up to 320MB/s• Up to 16 devices

– IDE / ATA• Cheap, common, easy

to setup• Somewhat unreliable

– Serial ATA• Introduced in 2002• 150MB/s• Hot-plugging capability• Serial Attached SCSI

Optical Media - CD

• CD-ROM, CD-R, CD-RW

• Typically store 700MB

• 1.8GB/$

Optical Media - DVD

• Digital Versatile Disc

• Typically store 4 to 17GB

• Standards– DVD, DVD-RAM, DVD-R,

DVD-R/W, DVD+R/W

• Non-standards– DVD-VCD, DVD-SVCD,

DVD-MP3

Optical Media - DVD

• Future Standards– DVD+RW DL

• 8.5GB• DVD+RW Alliance• Available now

– DVD HD• 20+GB• Toshiba and NEC• Available in 2005

– Blu-ray• 27GB on single

sided, single layer disc

• blue-violet laser • Panasonic,

Pioneer, Sharp, Samsung, Sony

Solid-State Storage Media

• No moving parts• Slow/fast• Very small• Generally used in cameras, PDAs, etc.• Several types

– CompactFlash (1GB)– Memory Stick (512MB)– Secure Digital (512MB)– Smart Media (128MB)

Security Concerns