How to handle mobile nodes? (Naming) Naming Use dHCP and update name-address mapping whenever host changes address FiXes contact problem but not broken transport connections 1-08-07 ecture 21: Wireless Networking 6
11-08-07 Lecture 21: Wireless Networking 6 How to Handle Mobile Nodes? (Naming) • Naming • Use DHCP and update name-address mapping whenever host changes address • Fixes contact problem but not broken transport connections
How to handle mobile nodes? (Transport) TCP currently uses 4 tuple to describe connection < Src Addr, Src port, Dst addr, Dst port> Modify tcp to allow peers address to be changed during connection Security issues Can someone easily hijack connection? Difficult deployment >both ends must support mobility 1-08-07 ecture 21: Wireless Networking 7
11-08-07 Lecture 21: Wireless Networking 7 How to Handle Mobile Nodes? (Transport) • TCP currently uses 4 tuple to describe connection • <Src Addr, Src port, Dst addr, Dst port> • Modify TCP to allow peer’s address to be changed during connection • Security issues • Can someone easily hijack connection? • Difficult deployment → both ends must support mobility
How to handle mobile nodes? (Link Layer) Link layer mobility Learning bridges can handle mobility this is how it is handled at Cmu Encapsulated PPP(PptP), Have mobile host act like he is connected to original lan Works for IP ANd other network protocols 1-08-07 ecture 21: Wireless Networking 8
11-08-07 Lecture 21: Wireless Networking 8 How to Handle Mobile Nodes? (Link Layer) • Link layer mobility • Learning bridges can handle mobility → this is how it is handled at CMU • Encapsulated PPP (PPTP) → Have mobile host act like he is connected to original LAN • Works for IP AND other network protocols
How to handle mobile nodes? (Routing) Allow mobile node to keep same address and name How do we deliver iP packets when the endpoint moves? Cant just have nodes advertise route to their address What about packets from the mobile host? Routing not a problem What source address on packet?> this can cause problems Key design considerations Scale Incremental deployment 1-08-07 ecture 21: Wireless Networking 9
11-08-07 Lecture 21: Wireless Networking 9 How to Handle Mobile Nodes? (Routing) • Allow mobile node to keep same address and name • How do we deliver IP packets when the endpoint moves? • Can’t just have nodes advertise route to their address • What about packets from the mobile host? • Routing not a problem • What source address on packet? → this can cause problems • Key design considerations • Scale • Incremental deployment
Basic Solution to Mobile routing Same as other problems in computer scIence Add a level of indirection Keep some part of the network informed about current location Need technique to route packets through this location(interception Need to forward packets from this location to mobile host(delivery) 1-08-07 ecture 21: Wireless Networking 10
11-08-07 Lecture 21: Wireless Networking 10 Basic Solution to Mobile Routing • Same as other problems in computer science • Add a level of indirection • Keep some part of the network informed about current location • Need technique to route packets through this location (interception) • Need to forward packets from this location to mobile host (delivery)