Mobile IPv 4 CCUCOMMANT LAB outline Mobile IP
Mobile IPv 4 CCU_COMM_ANT LAB
outline Mobile IP 的設計 Mobile IP 架構中的角色 Mobile IP 支援項目 MIPv 4 中的移動與換手 MIPv 4 中的詳細操作流程 MIPv 4 的問題 Questions CCU_COMM_ANT LAB
Mobile IPv 4 (MIP) Binding Update Data Transmission Corresponded Node (CN) Foreign Agent (FA) Home Agent (HA) Mobile Node (MN) Home Network CCU_COMM_ANT LAB Foreign Network
Mobile IP 中的支援項目 Agent Discovery ³ 搜索能力, 行動節點利用搜索程序來辦認可能的 home 及foreign agents. HA’s and FA’s broadcast their presence on each network to which they are attached Beacon messages via ICMP Router Discovery Protocol (IRDP) ® MN’s listen for advertisement and then initiate registration ® CCU_COMM_ANT LAB
Mobile IP 中的支援項目 Registration ³ ³ 註冊能力, 行動節點利用認証註冊程序來通知home agent 有關它管轄的轉交位址(care-of address). When MN is away, it registers its COA with its HA ® ³ Typically through the FA with strongest signal Registration control messages are sent via UDP to well known port Tunneling – 通道建立能力, 用來轉送IP datagrams 自home address 至care-of address. ³ 透過Encapsulation 及Decapsulation 來達成tunneling ® ® Encapsulation: 加入Co. A Decapsulation : 移除Co. A CCU_COMM_ANT LAB
Why Agent Discovery Mobile node 負責discovery process ³ 必須決定它是連接至home network 或是foreign network 從home network 轉換至foreign network任 何時候都可能發生 ³ ³ Mobile node 會收聽agent advertisement messages 將比對agent’s IP address 與home address 的 network 部份 如果這些網路部分不符合,表示MN是一個外地網路 上。 CCU_COMM_ANT LAB ®
Agent Solicitation 一般來說,Foreign agents 須定期發出agent advertisement messages 若mobile node 立刻需要agent information , 它可發ICMP router solicitation message ³ 任何agent 收到此訊息後會發出agent advertisement CCU_COMM_ANT LAB
Co. A (Care-of-address) Co. A 三部曲 ³ 1. 取得Care-of-Address (Discovering Care-of. Address) Internet Control Message Protocol (ICMP) Router Discovery ® Mobile Host也可以主動的broadcast 或者是multicast一個solicitation封包,來偵測現在 是否有Home Agent 或Foreign Agent的存在 ® CCU_COMM_ANT LAB
Co. A (Care-of-address) ³ 2. 註冊Care-of-Address (Registering Care-of. Address) ® ³ Home address,Care-of-Address,以及 Registration Lifetime,這三個元素又合稱為 Binding 3. Tunneling 至Co. A所在地-FA CCU_COMM_ANT LAB
Registration Process CCU_COMM_ANT LAB
Mobile IP Tunneling Across Internet CCU_COMM_ANT LAB
Mobile IP Tunneling 針對FA與HA之間的封包觀察,我們可以看 到tunneling 的結果 從內層的IP標頭看起來: 140. 123. 112. 240 (MN 的home-addr) 送到 140. 112. 8. 130(CN) 經過tunneling 會從 140. 123. 115. 42(FA-addr)轉 送給 140. 123. 112. 239(HA-addr) CCU_COMM_ANT LAB
Handoff scenario CCU_COMM_ANT LAB
Handoff process in MIPv 4 – TCP Connection When Mobile IP Is Used E: last ACK A: start handoff B: acquisition C: finished CCU_COMM_ANT LAB
Handoff process in MIPv 4 – TCP Connection When Mobile IP Is Used E: last ACK A: start handoff B: acquisition C: finished CCU_COMM_ANT LAB
Handoff process in MIPv 4 – TCP Connection When Mobile IP Is Used E: last ACK A: start handoff B: acquisition C: finished CCU_COMM_ANT LAB
Mobile IP 的問題 Security in Mobile IP Single HA model is fragile ³ Frequent reports to HA if MN is moving ³ Possible solution – have multiple HA Possible solution – support of FA clustering MIP的 handoff latency 會影響上層協定運作 ³ EX: TCP connection CCU_COMM_ANT LAB
Reference RFC 3344 - IP Mobility Support for IPv 4 CCU_COMM_ANT LAB
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