PowerPoint

5.1 #

#:

#Web

CNNIC#5.2 #

#

PANPersonal Area Network, LANLocal Area Network, MANMetropolitan Area Network, WANWide Area Network, #PANPersonal Area Network,

10

WLAN#LANLocal Area Network,

10Mbps~10Gbpsn10-12~10-7#WANWide Area Network,

Internet#RTT

#data ratebit rateb/sbpsbit per secondS=1/TT

#bandwidth

#Rmax=2fB=f=5 000Hz10 000bpsNyquistShannonRmaxBS/NRMAX=Blog2(1+S/N)RmaxbpsBHz#Pe=Ne/NNNe#throughput1000Mb/s1000Mb/s600Mb/s#delay latency

#

transmission delay

#

propagation delay

#

#

=+++

#=

#RTT

RTTRound-Trip TimeRTT

#

###ISO/OSIISOISOISO/IEC 7498X.2007OSIInterconnectionInteroperationPortability#ISO/OSIISO7ISO#ISO/OSI

#TCP/IPTCP/IPARPANETARPANETDoD(U.S.Department of Defense)TCP/IPTCP/IP reference model

#TCP/IPTCP/IPTCP/IP#TCP/IPTCP/IPOSI

#TCP/IP

Host-to-Net LayerOSIHDLCPPPSLIPInter-network LayerOSIIPICMPARPRARPTransport LayerOSITCPUDPApplication LayerOSIFTPHTTPDNSSMTPNFS#OSITCP/IP

OSITCP/IP# TCP/IPOSI

#OSITCP/IP1 2 OSITCP/IP1 2 3 OSI, TCP/IP, TCP/IP4 OSITCP/IP#5.3 ##4

#

# 5568B568A#

#

#

#TCP/IPInternetIPIPInternet TCP/IPInternet TCP/IP#

Internet TCP/IP

#

Windows 7#PingIPPing Ping192.168.194.35192.168.194.4192.168.194.35DOSping 192.168.194.4#TCP/IP Pinging 192.168.194.4 with 32 bytes of data: Reply from 192.168.194.4 : bytes =32 time