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Characteristics of communication links. Skills : none IT concepts : data transmission rate, latency, jitter, packet loss, medium. This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 License. Characteristics of communication links. Internet concepts - PowerPoint PPT Presentation
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Characteristics of communication links
Skills: none
IT concepts: data transmission rate, latency, jitter, packet loss, medium
This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 License.
Characteristics of communication links
• Internet concepts– Applications– Technology (connectivity)– Implications for
• Individuals• Organizations• Society
• Internet skills– Application development– Content creation
• Text• Image• Audio• Video
Link characteristics
1. Speed
2. Latency
3. Jitter
4. Packet loss rate
5. Medium
Do you know the speed of the link between your home and your ISP?
LAN router
ISP router
Home LAN
The Internet
What is the unit of measure for data transmission speed?
Measure of Example units Rate ratio
Distance Inches, miles, light years
Rate of movement Miles/hour, inches/year
Distance/time
Weight Ounces, tons, grams
Amount of data Bits, bytes, gigabytes
Rate of data transmission
? ?
What is the unit of measure for data transmission speed?
Measure of Example units Rate ratio
Distance Inches, miles, light years
Rate of movement Miles/hour, inches/year
Distance/time
Weight Ounces, tons, grams
Amount of data Bits, bytes, gigabytes
Rate of data transmission
Bits/second, bytes/second, gigabits/second
Amount of data/time
Plan Speed down Speed up Price
Starter DSL 1 Mbps 384 Kbps $19.99
Power DSL 3 Mbps 768 Kbps $29.99
Turbo DSL 7.1 Mbps 768 Kbps $42.99
FIOS fast 15 Mbps 5 Mbps $49.99
FIOS faster 25 Mbps 15 Mbps $64.99
FIOS fastest 50 Mbps 20 Mbps $144.99
Verizon Internet plans, November 2009
Note that speeds are “up to” these rates.
Note the asymmetry in upload and download speed.
Prefixes for large quantities
Prefix Exact Close enough Name
Kilo 1,024 1,000 Thousand
Mega 1,024^2 1,000,000 Million
Giga 1,024^3 1,000,000,000 Billion
Tera 1,024^4 1,000,000,000,000 Trillion
Peta 1,024^5 1,000,000,000,000,000 Quadrillion
After these prefixes come exa, zetta and yotta. The pattern continues -- each is 1,024 times the previous one.
Availability of 100 Mbps service in 2009
Follow this link for 100 Mbps cost.
Latency – the time for the first packet to arrive
About half the ping (round trip) time
Jitter – variation in latency
Ping time and jitter from Los Angeles
Distance(miles)
P1(ms)
P2(ms)
P3(ms)
P4(ms)
Avg.(ms)
Jitter(st dev)
SantiagoChile 5,585 412 346 228 225 303 92.08
OxfordEngland 5,408 195 194 195 193 194 .96
Packet loss rate
No packets lost -- packet loss is rare, but occurs
Packet loss rate from SLAC (Palo Alto, CA)
•Steady improvement everywhere but Africa•All regions but Africa an parts of Asia are now under 1%
Current year data on Verizon backbone latency, packet loss rate and jitter
http://www.verizonbusiness.com/about/network/latency/
Transfer rate from SLAC (Palo Alto, CA)
Copper, twisted pair
Copper, coaxial cable
Fiber
Terrestrial radio
Satellite radio
Link medium
We just covered five characteristics of a communication link. Do you recall what they were?
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