16. 16 NETWORKING FUNDAMENTALS
Connection Speed Text Graphics Multimedia
Type
20 kB 100 kB 2 MB
Dial-up (V.90) 56 kbps 2.9 s 14.6 s 5 min
ADSL basic 512 kbps 320 ms 1.6 s 32.8 s
typical 2 Mbps 82 ms 410 ms 8.4 s
premium 8 Mbps 20.5 ms 102 ms 2.1 s
Cable typical 512 kbps 320 ms 1.6 s 32.8 s
premium 2 Mbps 82 ms 410 ms 8.4 s
Satellite† 512 kbps 860 ms 2.1 s 33.3 s
Leased T1 1.5 Mbps 109 ms 546 ms 11.2 s
line
T3 44 Mbps 3.7 ms 19 ms 381 ms
G3 phone 2 Mbps 82 ms 410 ms 8.4 s
Abilene 100 Mbps 1.6 ms 8.2 ms 168 ms
† Includes latency.
Figure 16.1. Typical download times
Clients and Servers
18. HTTP (HyperText Transfer Protocol)
•àเ»ปšš¹น protocol áแºบºบ§ง‹‹ÒาÂย·ท∙Õี่ÍอÍอ¡กáแºบºบàเ¾พ×ื่ÍอãใËหŒŒ´ดÓำàเ¹นÔิ¹น¡กÒาÃรÃรÑัºบ
Êส‹‹§งÍอÂย‹‹Òา§งÃรÇว´ดàเÃร็Çว¢ขÍอ§ง¢ขŒŒÍอÁมÙูÅลáแºบºบ hypermedia ÃรÐะËหÇว‹‹Òา§ง
Web Server (server) ¡กÑัºบ Web Browser (client)