【正文】 ............................ 27 三、設(shè)計(jì)依據(jù)與應(yīng)用標(biāo)準(zhǔn) ............................................. 28 網(wǎng)絡(luò)標(biāo)準(zhǔn)與規(guī)范 .................................................. 30 標(biāo)準(zhǔn)與協(xié)議 ...................................................... 31 網(wǎng)絡(luò)協(xié)議 ........................................................ 31 四、設(shè)計(jì)思想 ....................................................... 32 網(wǎng)絡(luò)設(shè)計(jì)思想 .................................................... 32 1高可用性 ...................................................... 32 2冗余的考慮 .................................................... 33 3采用 IP 組播 ................................................... 33 4QoS 和超額配置 ................................................. 33 湛江市教育城域網(wǎng)技術(shù)建議書(shū) 3 5虛擬 LAN（ VLAN） ............................................... 34 6安全性和可靠性 ................................................ 34 7前瞻性 ........................................................ 34 8兼容性 ........................................................ 35 9經(jīng)濟(jì)性 ........................................................ 35 10演繹性 ....................................................... 35 11競(jìng)爭(zhēng)性 ....................................................... 35 12從技術(shù)的角度出發(fā) ............................................. 35 13從用戶的角度出發(fā) ............................................. 35 14從應(yīng)用出發(fā) ................................................... 35 15穩(wěn)健性 ....................................................... 35 五、網(wǎng)絡(luò)設(shè)計(jì)原則 ................................................... 37 高可靠性 ........................................................ 37 獨(dú)立性 .......................................................... 37 技術(shù)先進(jìn)性和實(shí)用性 .............................................. 38 高性能 .......................................................... 38 標(biāo)準(zhǔn)開(kāi)放性 ...................................................... 38 自愈能力 ........................................................ 38 擁塞控制與服務(wù)質(zhì)量保障 .......................................... 39 網(wǎng)絡(luò)的擴(kuò)展能力 .................................................. 39 兼容性和經(jīng)濟(jì)性 .................................................. 40 通信協(xié)議的支持 ................................................. 40 1網(wǎng)絡(luò)管理與安全體系 ............................................. 40 1統(tǒng)一標(biāo)準(zhǔn)、統(tǒng)一平臺(tái) ............................................. 41 1網(wǎng)絡(luò)整體規(guī)劃適度超前，分層建設(shè) ................................. 41 1 IP 組播 Multicast............................................... 41 六、設(shè)計(jì)目標(biāo) ....................................................... 42 高帶寬 .......................................................... 42 湛江市教育城域網(wǎng)技術(shù)建議書(shū) 4 高可靠性 ........................................................ 42 可擴(kuò)展性和可升級(jí)性 .............................................. 42 多協(xié)議支持 ...................................................... 42 易管理、易維護(hù) .................................................. 42 安全性 .......................................................... 43 QoS 服務(wù)質(zhì)量保證 ................................................ 43 IP組播 Multicast................................................ 43 符合國(guó)際標(biāo)準(zhǔn) .................................................... 43 性能價(jià)格比 ..................................................... 43 1網(wǎng)絡(luò)建設(shè)目標(biāo) ................................................... 43 1確保技術(shù)具有先進(jìn)性、成熟性 ..................................... 44 1提供學(xué)校接入服務(wù) ............................................... 44 1提供豐富的教育資源 ............................................. 44 七、系統(tǒng)結(jié)構(gòu) ....................................................... 45 標(biāo)準(zhǔn)的網(wǎng)絡(luò)分層結(jié)構(gòu) .............................................. 45 1核心層 ........................................................ 45 2匯聚層 ........................................................ 46 3接入層 ........................................................ 46 網(wǎng)絡(luò)結(jié)構(gòu)設(shè)計(jì) .................................................... 47 1核心層 ........................................................ 48 2匯聚層 ........................................................ 48 3接入層 ........................................................ 48 4核心設(shè)備部署 .................................................. 49 5市教育局設(shè)備部署 .............................................. 49 6縣教育局設(shè)備部署 .............................................. 49 八、網(wǎng)絡(luò)系統(tǒng)設(shè)計(jì) ................................................... 51 湛江市教育城域網(wǎng)設(shè)計(jì) ............................................ 51 1核心層 ........................................................ 51 湛江市教育城域網(wǎng)技術(shù)建議書(shū) 5 1 安全規(guī)劃 ................................................... 52 2 設(shè)備間連接方式 ............................................. 53 2分布 /匯聚層 ................................................... 53 1 安 全規(guī)劃 ................................................... 53 2 設(shè)備間連接方式 ............................................. 54 3接入層 ........................................................ 54 1 安全規(guī)劃 ................................................... 55 2 設(shè)備間連接方式 ............................................. 55 4出口城域網(wǎng)絡(luò)設(shè)計(jì) .............................................. 55 5方案設(shè)計(jì)優(yōu)勢(shì) .................................................. 57 1 網(wǎng)絡(luò)拓?fù)潇`活擴(kuò)展 ........................................... 57 2 技術(shù)先進(jìn)、適用 ............................................. 57 3 高速平臺(tái)具備高擴(kuò)展能力 ..................................... 57 4 可靠性技術(shù)保證 ............................................. 57 5 管理全面高效 ............................................... 58 6 建設(shè)和維護(hù)成本合理性 ....................................... 58 九、骨干網(wǎng)選擇 ..................................................... 59 IP over ATM..................................................... 60 1ATM 技術(shù)的復(fù)雜性 ............................................... 61 2 、 IP over SDH.................................................... 65 IP Over Gigabit Ether......