Title: ??: 3.?????Circuit-switched networks ?
1?????? ??
?? 3.?????Circuit-switched networks ?
Packet- switched networks???
4.????????????????????
???????????????????(? ?????)
?????
??935602 ??? 935604 ??? 935625 ???
935627 ??? 935645 ??? 935651 ???
935657 ???
2?????Circuit-switched networks?Packet-switched
networks ???
Packet-switched networks ??? 1. ????????????(Wide
Area Network, WAN)?2. ?????????(LAN)????????????
?????????????????3. ?????????(Intranet)??????(Ex
tranet)?????? 4. ??ITU(?CCITT)??????,???????????
??,???????????,?????5. ???????????????????????
??????,??????????,???????????????????,?????????,??
?????,?????????????,?????????,????????????????????
???
36. ????????????????????????,??????????,?????????
?????,????????????(Bits Error RateBER)??
,??????????????? ,???????????????????????7.
????????????????????????,?????????(CUG)?????(PVC
)??????(NUI)???????(VPN)???,???????????? 8.
?????????????????????????????????,??????????????
,??????????? 9. ???????????,???????????????????
????????,?????????????,??????????????????,????????
?????????????,???????????????????,???????????????
10. ??????????????????????(Gateway),??????????
?????????,????????????????????
4 11. ???????????????????,???????????????????????
?,??????????????,??????????????,??????????(VPN)???
????,????????????????????12. ?????????????????
???????????,???????????????,?????????????,????????
?????????? (1) ?????(Pernament Virtual
CircuitPVC)?????????????(Logical
Channel)???(??)?,?????????????????????? (2)
?????(Switched Virtual CircuitSVC)?????????????(
Logical Channel)????(???),?????????,??????????????
,????????????,???????,???????????
5(3) ????(Closed User Group)??????????????????,???
???????????,??????????,????????????? (4)
????(Hunt Group-Collective Number
Group)???????????????????????????????,???????,???
?????????,????????,???????????????????????? (5)
??????(Virtual Private NetworkVPN)????????,?????
????,?????????????????,????????????,??????????????
???,??????(VPN)???????????????,??????????????????
???? ? ?????? ? ???????? ?
????,???? ? ????,????? ? ???????? ?
???????? ? ??????? ? ????????????
6(6) ??????(VPN)?????? ? ????????????????
? ???????????? ? ?????????????? ?
???????????????????? ? ???????????????????
? ?????????????? ? ???????????
7- Circuit-switched networks ???
- 1.???????(dedicated),????????
-
- 2.?????????????,??????????????,?64Kbps??????,?????
,?????????,??????????,??????????(full duplex)
?????,??? connection oriented? - 3.???????????
- ???? ( FDMFrequency Division Multiplexing )
- ??????????????????????
- ???? ( TDMTime Division Multiplexing )
- ??????????????????????
- ???????????????? ( Guard Time ),???????????????
8???????????????????????????????????????(??????)
?
?????????????????? ??????????????????????????,???
????,??,??,?????,???????,???????
1?????????????????????????,??????????????????????
???????????,?????????????,????????????????,???????
?????,??????????????,??????????,?????????????????
2???????????????????????,??100M??(?????,???????),
??????????,????????100M,???????????????????,?????1
00M????(?568B?568A)?? ?
93????????????????????????????????,??????????????
4?????????,????????????????????????,????????(???CP
U????,??,??,??)???????????????,????????????
5????????????(???????)?????????????,????????,????
???????????????????
10 ???????????CAT7?CAT8,CAT7?????600MHz,CAT8??1.2
GHz,CAT8????????????IBM???3P(Third Party
Testing)??????????,??????????Enterprise(??)?Home(?
?) ?Mobility(??) ,???????????????????,???????????(
Entertainment)????????????,????????????????(Video
on Demand)????????,?????????????????????????(100?)
??,????CAT8????SOHO???????????????,???CAT8??????1.
2GHz?50??????(Channel),????????,??????????????(Thi
n Client)????,?????????????????????,??????????????
???????,???????????????????,???????????????????
11???? Cat3 Cat3 Cat5 Cat5 Cat5e Cat5e Cat6 Cat6 Class C Class C Class D Class D Class E Class E Class F Class F
???? PL CH BL PL PL CH PL CH PL CH PL CH PL CH PL CH
??(Attenuation) ??dB 13.0 14.9 21.6 24.0 21.0 24.0 31.1 36.0 12.6 14.9 20.4 24.0 30.7 35.9 46.6 54.6
????(NEXT) ??dB 21.0 19.2 29.3 27.1 32.3 30.1 35.3 33.1 21.1 19.3 32.3 30.1 35.3 33.1 54.7 51.2
??????(PSNEXT) ??dB ? ? ? ? 29.3 27.1 32.7 30.2 ? ? 29.3 27.1 32.7 30.2 51.7 48.2
?????(ACR) ??dB ? ? ? ? ? ? ? ? ? ? 11.9 6.1 4.7 -2.8 8.1 -3.4
???????(PSACR) ??dB ? ? ? ? ? ? ? ? ? ? 8.9 3.1 2.0 -5.8 5.1 -6.4
???????(ELFEXT) ??dB ? ? 17.0 17.0 18.6 17.4 16.2 15.3 ? ? 18.6 17.4 16.2 15.3 32.6 31.3
12????????(PSELFEXT) ??dB ? ? 14.4 14.4 15.6 14.4 13.2 12.3 ? ? 15.6 14.4 13.2 12.3 29.6
????(Return Loss) ??dB ? ? 10.1 8.0 12.0 10.0 10.0 8.0 15.0 15.0 12.0 10.0 10.0 8.0 10.0
????(Propagation Delay)??nSec ? ? 518 555 498 555 498 555 498 555 498 555 498 555 498
????(Delay Skew) ??nSec ? ? 45 50 44 50 44 50 44 50 44 50 44 50 26
???? 16MHz 16MHz 100MHz 100MHz 100MHz 100MHz 250MHz 250MHz 16MHz 16MHz 100MHz 100MHz 250MHz 250MHz 600MHz 600MHz
?? ????????????
13PL??????? BL??????? CH?????
????? ??????????
??????? ???????????????????????????????
???? ????????????????????????????????
????? ??????????
??????? ???????????????????????
???? ????????????????????????,???????,????????,?????
???? ????????????
???? ????????????
?? ????????????