C S SAP ) LOP con hOMU Ogc M
331 Type (3) BR /ASS (II)
4.2. MOI TRIANG MO PHONG
Moi throng thvc hien mo phong la NS-2 (Network Simulator) phial ban 2.31. NS-2 la mOt cong cu ma ngtnin ma cho phep m8 ph6ng mang chuyen mach goi, hi!) trq m6 phong cac giao thirc nhu TCP, UDP, cac giao thirc djnh tuyen, giao thirc lap MAC tren m8i truing mang vo tuyen vi haw tuyen nhu wireless LANs, Mobile Ad hoc Networks (MANETs), mang
NS-2 la mOt dun vi mo phong huang d6i ttrqng. CAu trim ngOn ngfr bao g6m hai thanh phan: nen nga. huding d6i arcing C++ va OTCL duct phan biet theo 2 mire dieu khien va mirc xir li goi. C++ duqc sir dung de xir li mire goi trong khi OTCL duqc sir dung de djnh nglita cac thong se) cau hinh mo ph6ng nhu topology mang, kieu dun vi thai diem khai dau va lc& thk luong du Ru, IciEu lain yen dinh danh nut nguein va dich...
Mac du vay, phien ban NS-2 2.31 khong ho trq m6 phong cac thanh phan cua
chuan IEEE 802.16. do do, trong luan van nay co sir dung module WiMax cho NS-2 do MIT phat trier (tich hqp cho phAn mem mo phong NS-2 verison 2.31).
Module WiMAX for NS-2 duqc thiet ke vi phat then boi cac thanh vien cua
Networks and Distributed Systems Laboratory (NDSL) vi Computer Science and Information Engineering thutjc dai hvc Chang Gung, Dai Loan.
Chuang 4: Me) phong hogs clOng hg thong WiMAX
Traffic Generating Agent
V — — r• .., 41- Link Layer (LL) 1 Interface Queue (IFQ)
i I Radio Propagation Model WINO& Interface Channel
Hinh 4.1. Module WiMAX trong kiln trot NS-2 [13]
Trong kiln true tren, mOt nut wireless bao g6m cac thinh phial: Traffic Generating Agent (address classifier, port classifier, agent protocol, agent routing), lop LL (Link Layer), lop MAC, hang dqi va kenh vat ly. Cac classifier chit' trach nhiem phan ph6i cac g6i Wang Ung voi cac agent. Agent protocol bieu din cho lop application va agent routing Neu dien cho lop IP. Khi meg packet di tir agent protocol den agent routing, agent routing se dat dja chi cua dich vao goi va chuyen
tiap den lop LL. Lop LL sir dvng giao thine phan giii dia chi ARP (Address Resolution Protocol) de xac djnh dja chi MAC dm dich. Lop LL dat dia chi MAC cua dich vao g6i va chuyen den 16p MAC. Lop MAC se thvc hien cac chirc nang tucmg Ung va xac djnh theri diem gfri goi ten kenh. Sau d6, chuyen goi den lop vat IS. Lop vat 1S, chit' trach nhiem girl g6i tren kenh wireless den not nhan.
Module WiMAX thvc hien m8 phemg 16p con phan chung MAC chuan IEEE 802.16 trong NS-2. Cv the, cac thanh phan dugc thvc thi trong module:
Co the cap phat bang thong GPC (Grant per Connection).
Chuang 4: MO phong hoot tang thong WiMAX
Tao va truyen MAC PDU (Lai BS va SS), !lan manh va eking ed.
Ca the lap lich Oren kenh uplink, downlink) bon kieu dich vu (UGS, rtPS, nrtPS, BE).
Module thvc thi 16p MAC IEEE 802.16 c6 vai tro tacmg tv nhu module IEEE
802.11 va duqc dat trong cling thu mtic —/mac trong NS-2.