{"id":19317857,"url":"https://github.com/queeniecplusplus/ccna2020_ospf","last_synced_at":"2026-03-02T19:02:58.089Z","repository":{"id":104588138,"uuid":"296778438","full_name":"QueenieCplusplus/CCNA2020_OSPF","owner":"QueenieCplusplus","description":"開放最快路徑優先","archived":false,"fork":false,"pushed_at":"2020-09-19T06:19:07.000Z","size":960,"stargazers_count":0,"open_issues_count":0,"forks_count":0,"subscribers_count":2,"default_branch":"master","last_synced_at":"2025-01-06T04:26:16.005Z","etag":null,"topics":["ospf","ospf-vulnerability-checking","ospfv2","ospfv3"],"latest_commit_sha":null,"homepage":"https://github.com/QueenieCplusplus/QuickGoThru/blob/master/README.md#ccna-revsersion-in-2020","language":null,"has_issues":true,"has_wiki":null,"has_pages":null,"mirror_url":null,"source_name":null,"license":null,"status":null,"scm":"git","pull_requests_enabled":true,"icon_url":"https://github.com/QueenieCplusplus.png","metadata":{"files":{"readme":"README.md","changelog":null,"contributing":null,"funding":null,"license":null,"code_of_conduct":null,"threat_model":null,"audit":null,"citation":null,"codeowners":null,"security":null,"support":null,"governance":null,"roadmap":null,"authors":null,"dei":null,"publiccode":null,"codemeta":null}},"created_at":"2020-09-19T03:26:56.000Z","updated_at":"2020-09-19T06:19:10.000Z","dependencies_parsed_at":null,"dependency_job_id":"8c6c6f51-01b0-47c6-a3bd-242a79f56416","html_url":"https://github.com/QueenieCplusplus/CCNA2020_OSPF","commit_stats":null,"previous_names":[],"tags_count":0,"template":false,"template_full_name":null,"repository_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/QueenieCplusplus%2FCCNA2020_OSPF","tags_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/QueenieCplusplus%2FCCNA2020_OSPF/tags","releases_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/QueenieCplusplus%2FCCNA2020_OSPF/releases","manifests_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/QueenieCplusplus%2FCCNA2020_OSPF/manifests","owner_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners/QueenieCplusplus","download_url":"https://codeload.github.com/QueenieCplusplus/CCNA2020_OSPF/tar.gz/refs/heads/master","host":{"name":"GitHub","url":"https://github.com","kind":"github","repositories_count":240420941,"owners_count":19798501,"icon_url":"https://github.com/github.png","version":null,"created_at":"2022-05-30T11:31:42.601Z","updated_at":"2022-07-04T15:15:14.044Z","host_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub","repositories_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories","repository_names_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repository_names","owners_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners"}},"keywords":["ospf","ospf-vulnerability-checking","ospfv2","ospfv3"],"created_at":"2024-11-10T01:16:28.308Z","updated_at":"2026-03-02T19:02:58.012Z","avatar_url":"https://github.com/QueenieCplusplus.png","language":null,"funding_links":[],"categories":[],"sub_categories":[],"readme":"# CCNA_OSPF\n開放最快路徑第一\n\n# 應用情境\n\n如果說網管們在設計網路架構時，靜態路由 \u003e 動態路由，真要用到動態路由，則觀看公司規模，\n如果是小型企業，大多使用動態路由中的 RIP 路由協定，倘若規模稍大為中大型企業，\n則動態路由會建議使用 OSPF 開放最短路徑優先的路由協定。\n\n# IGP \u0026 EIGP\n\nIGP 為 Interil Gateway Protocol, 與 EIGP (Enhanced Interior GW Protocol) 相互應。\n而 OSOF 算是 IGP 中比較常見的動態路由協定。\n\n# 路徑演算法\n\n動態路由協定中常見的 RIP 與 OSPF 就是分別使用不同的演算法，前者屬於計算 hop count 的 distance vector，\n而後者屬於觀察 Link State 鏈結狀態，兩者不同，一個是基於實體路徑 hop 數量，另一個是基於 cost 傳輸質量。\n\n# LSDB 資料表紀錄\n\n類似資料庫，同一區域的路由器的資料表都會是一樣的。\n\n# LSDB 資料表更新\n\n採用 Link State Update 鏈結狀態更新，使用 Multicast 224.0.0.5 和 224.0.0.6 來傳送資料表更新訊息。\n\n# IP port\n\nOSPF 與其他動態路由協定不同的是，它不經由 TCP、UDP，僅使用 IP 層，IP port 是 89。\n\n# Backbone 骨幹區域與骨幹路由器\n\n即兩個非骨幹區域邏輯性地相互連接的區域。\n骨幹區域負責分配路由資訊給非骨幹路由。\n\n\n![ospf](https://raw.githubusercontent.com/QueenieCplusplus/CCNA2020_OSPF/master/ASBR.png)\n\n\nR2 \u0026 R3 兩路由器均開啟了 OSPF，所以為骨幹路由器。\n\nR2 \u0026 R3 兩路由器也有端口開啟了 AS 內的鏈路狀態路由表的更新監聽，所以也為區域邊界路由器 ABR。\n\n( R2 為 ASBR 會需要更多的記憶體資源和更高效能的處理器，因為它要面對多動態協定的路由訊息。)\n\nR1 \u0026 R5 只需要維護該區域 Area1 的 LSDB (包含紀錄拓樸狀態的變化、包含 LSA 的 flood)。\n\nR3 \u0026 R4 只需要維護該區域 Area2 的 LSDB (包含紀錄拓樸狀態的變化、包含 LSA 的 flood)。\n\nArea 0 IP 為 0.0.0.0，使兩個以上不同的區域彼此間能展開訊息交流。\n\n# Stub 末梢區域\n\n設定一預設路由，控管區域內外進出的路由資訊，避免區域外部資訊對區域內部進行泛洪。\n\n(尚區分為完全末梢、不完全末梢)\n\n# 傳播更新資訊的方式\n\n\n![multicast](https://raw.githubusercontent.com/QueenieCplusplus/CCNA2020_OSPF/master/multicast.png)\n\n\n* PTP (點對點，多播)\n\n  用組播位址 224.0.0.5 傳送 OSPF 協定封包到其他 PSPF 路由器。\n\n* Broadcast (廣播)\n\n  在廣播網路上的 OSPF 路由器會選舉一台指定路由器（DR）和一台備份指定路由器（BDR）。\n  所有其他的路由器都將使用目的位址 Des Addr 224.0.0.6，以組播方式傳送 OSPF 封包到 DR 和 BDR，\n  所有始發於 DR 和 BDR 的 OSPF 封包使用目的位址 Des Addr 224.0.0.5，以組播方式傳送到所有其他 OSPF 路由器。\n\n* NBMA, 非廣播多路(單播)存取\n\n  需要選舉 DR 和 BDR，並且所有的 OSPF 封包都是單播 Unicast 傳送的。\n  常見於 Ｘ.25。\n\n* 點到多點（多播）\n\n  點到多點網路上 OSPF 的行為和 點到點網路 OSPF 的行為一樣，\n  也使用組播位址 224.0.0.5 傳送 OSPF 協定封包到其他 PSPF 路由器。\n\n# DR \u0026 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