台北科技大学：《计算机网络》（英文版） NP04 27 Mobile ip discussion overview

Mobile ip Overview Chuan-Ming liu Computer Science and Information Engineering National Taipei University of Technology Spring 04

Mobile IP – Overview Chuan-Ming Liu Computer Science and Information Engineering National Taipei University of Technology Spring ‘04

Mobile ip discussion overview o Will coⅴer: o Why IP routing breaks under mobility o Mobile ipva basics o Some low-level protocol details(message formats, headers, etc.) o Lots more detail in the specifications(see RFC)

Mobile IP Discussion Overview  Will cover: ⚫ Why IP routing breaks under mobility ⚫ Mobile IPv4 basics ⚫ Some low-level protocol details (message formats, headers, etc.)  Lots more detail in the specifications (see RFC)

Why Mobile Ip? o Laptop computing o Wireless technologies o Mobility v.S. Portability o Making mobility transparent to applications

Why Mobile IP?  Laptop Computing  Wireless Technologies  Mobility v.s. Portability  Making mobility transparent to applications

IP Addresses o Two parts Routing prefix(determined by the netmask) network on which the address resides Host number host on the network 32 bits routing prefix host number

IP Addresses  Two parts: ⚫ Routing prefix (determined by the netmask) network on which the address resides ⚫ Host number host on the network routing prefix host number 32 bits

Two-level Addressing o Applications use ip addresses to identify routes by which datagrams may be exchanged between network nodes o applications also use ip addresses to find the endpoints o The delivery of packets consists of o Routing to the destination network o Sending to the host

Two-level Addressing  Applications use IP addresses to identify routes by which datagrams may be exchanged between network nodes  Applications also use IP addresses to find the endpoints  The delivery of packets consists of ⚫ Routing to the destination network ⚫ Sending to the host

Two-level Addressing o Things are different when changing ones point of attachment to the internet o Mobile node mn, or mobile host (MH), in the mobile computing environment may change its point of attachment to the internet say from 140.124.182Xto128.10.7Z

Two-level Addressing  Things are different when changing one’s point of attachment to the internet.  Mobile node (MN) , or mobile host (MH), in the mobile computing environment may change its point of attachment to the internet, say from 140.124.182.X to 128.10.7.Z

MN140124.182X R 140124.182 Internet 128.107 R 128.10.7Z MN140124182X

R R 140.124.182 128.10.7 Internet MN 140.124.182.X MN 140.124.182.X 128.10.7.Z

What is mobile p o Modification to ip that allows nodes to continue to receive datagrams no matter where they happen to be attached to the Internet o Scalability has been a dominant design factor o Recall that ip can identify a node on the internet uniquely

What is Mobile IP  Modification to IP that allows nodes to continue to receive datagrams no matter where they happen to be attached to the internet  Scalability has been a dominant design factor  Recall that IP can identify a node on the internet uniquely

If no mobile p o Two ways to support mobility o Change IP address whenever it changed its point of attachment o host-specific routes must be propagated throughout the relevant portion of the Internet routing infrastructure o above two approaches are not acceptable

If no Mobile IP  Two ways to support mobility ⚫ Change IP address whenever it changed its point of attachment ⚫ Host-specific routes must be propagated throughout the relevant portion of the Internet routing infrastructure  Above two approaches are not acceptable

Two Addresses for mobile p Mobile ip solves this by maintaining two addresses One identifies a communication endpoint Chome address o The other locates the mobile computer care-of address

Two Addresses for Mobile IP Mobile IP solves this by maintaining two addresses: ⚫ One identifies a communication endpoint (home address) ⚫ The other locates the mobile computer (care-of address)