Access net:home network wireless <C devices to/from headend or central office often combined in single box cable or DSL modem wireless access router,firewall,NAT point(54 Mbps) wired Ethernet(100 Mbps) Introduction 1-16
Introduction Access net: home network to/from headend or central office cable or DSL modem router, firewall, NAT wired Ethernet (100 Mbps) wireless access point (54 Mbps) wireless devices often combined in single box 1-16
Enterprise access networks (Ethernet步 institutional link to ISP(Internet) institutional router Ethernet institutional mail, switch web servers typically used in companies,universities,etc 10 Mbps,100Mbps,1Gbps,10Gbps transmission rates today,end systems typically connect into Ethernet switch Introduction 1-17
Introduction Enterprise access networks (Ethernet) typically used in companies, universities, etc 10 Mbps, 100Mbps, 1Gbps, 10Gbps transmission rates today, end systems typically connect into Ethernet switch Ethernet switch institutional mail, web servers institutional router institutional link to ISP (Internet) 1-17
Wireless access networks shared wireless access network connects end system to router via base station aka"access point" wireless LANs: wide-area wireless access within building (100 ft) provided by telco (cellular) ■ 802.11b/g(Wifi):11,54 operator,10's km Mbps transmission rate between 1 and 10 Mbps ·3G,4G:LTE to Internet to Internet Introduction 1-18
Introduction Wireless access networks shared wireless access network connects end system to router via base station aka “access point” wireless LANs: within building (100 ft) 802.11b/g (WiFi): 11, 54 Mbps transmission rate wide-area wireless access provided by telco (cellular) operator, 10’s km between 1 and 10 Mbps 3G, 4G: LTE to Internet to Internet 1-18
Host:sends packets of data host sending function: takes application message two packets, breaks into smaller L bits each chunks,known as packets, of length L bits transmits packet into access network at R:link transmission rate transmission rate R host ■link transmission rate,aka link capacity,aka link bandwigseket time needed to L(bits) transmission transmit L-bit delay packet into link R(bits/sec) 1-19
Host: sends packets of data host sending function: takes application message breaks into smaller chunks, known as packets, of length L bits transmits packet into access network at transmission rate R link transmission rate, aka link capacity, aka link bandwidth R: link transmission rate host 2 1 two packets, L bits each packet transmission delay time needed to transmit L-bit packet into link L (bits) R (bits/sec) = = 1-19
Physical media bit:propagates between transmitter/receiver pairs physical link:what lies twisted pair(TP) between transmitter two insulated copper receiver wires guided media: Category 5:100 Mbps,1 Gpbs Ethernet signals propagate in solid media:copper, Category 6:10Gbps fiber,coax unguided media: signals propagate freely, e.g.,radio Introduction 1-20
Introduction Physical media bit: propagates between transmitter/receiver pairs physical link: what lies between transmitter & receiver guided media: signals propagate in solid media: copper, fiber, coax unguided media: signals propagate freely, e.g., radio twisted pair (TP) two insulated copper wires Category 5: 100 Mbps, 1 Gpbs Ethernet Category 6: 10Gbps 1-20