Fast Handover in Mobile IPv4 and IPv6

Raoul Schmidiger & Gregor Zographos

April 28, 2005

Seminar: Mobile Systems Talk No.4

Content

� IPv4 (Gregor)

� IPv6 (Raoul)

� Problems in IP mobility(Gregor)

� Standards in Mobile IP (Gregor)

� Mobile IP (Gregor)

� Fast Handover in Mobile IPv4 (Gregor)

� Fast Handover in Mobile IPv6 (Raoul)

� Summary (Raoul)

� Discussion (Gregor & Raoul)

IPv4

� From Jon Postel in RFC791 anno 1981

� 4th Version of the Internet Protocol (IP)

� 32-Bit addresses length � 24-Bit for the network part

� 8-Bit for the host part

� 130.60.48.7 (ifi IP)

� IP-Packet (1500 Bytes)� Header (Informations about source, goals, status, fragments etc.)

� Payload (includes transporting datas)

IPv4

� Make no differences between Hosts/Routers

� IANA diversify the IP-adresses worldwide

� In several classes, reserved for special purposes (broadcast, multicast etc.)

� 4‘294‘967‘296 definite addresses possible

� Future…

IPv6

� IPv6 aka Next Generation Internet Protocol (IPng)

� Introduced by Internet Engineering Task Force (IETF) in 1994 (RFC 1752)

� Designed to run well in high performance networks as well as lowbandwith networks (e.g. wireless)

� Existing internet devices can be “upgraded” to IPv6 through software installation

� Interoperable with IPv4 – a must if introduction of IPv6 is to be successful

� Introduces new internet functionality

Why IPv6?

� Growth of interconnected computers so far was exponentialThe next phase of growth will probably not be driven by the computer market, but in markets that are extremely large - current generation of cellular phones, pagers, and personal digital assistants (Nomadic personal computing devices)- On demand TV etc.- Device control

� Additional needs next to an internet protocol are:- low overhead- autoconfiguration- mobility- built-in authentification and confidentiality

Changes from IPv4 to IPv6

� Expanded Routing and Addressing Capabilities (adress size now 128 bits)

� "anycast address"

� Header Format Simplification

� Improved Support for Options

� Quality-of-Service Capabilities

� Authentication and Privacy Capabilities

IPv6 Adress (1)

� Unicast, anycast, multicast

� Adress space now slightly bigga:340’282’366’920’938’463’463’374’607’431’768’211’456

� But practically only 8x10^17 to 2x10^33 will be used.

� Internet adress in HEX:

http://[2a2f:9230:70fe:000e:d108:4b4c:7331:2ff0]/

� IPv4 Adress will be stored in the low-order 32-bits to allow the gradual transition from IPv4

IPv6 Adress (2)

� Routing included in Adress:- Provider Selection (based on policy, performance, cost, etc.) - Host Mobility (route to current location) - Auto-Readdressing (route to new address)

Adress contains source and destination AND optionally intermediate Nodes such as providers etc.a) Request: H1,H2 Response: H2,H1b) Request: H1,P1,P2,P3,H2 Response: H2,P3,P2,P1,H1c) …

� 2 build in types of security:- IPng Authentication Header - IPng Encapsulating Security Header

Problems in IP mobility

� Definite address for each internet user

� Changing cell - changing address?

� What about packet-sending during the change of a cell?

� The solution of Internet Protocol mobility are Mobile IP!

Standards in Mobile IP

� Transparency� Mobile End-system keeps the IP-address during network-change

� Resumption of communication after the network-change

� Compatibility� No changes in Layer-2-Protocolls

� No changes on Router and fixnet systems

� Communication between mobile and fixnet systems

Standards in Mobile IP

� Security� Authentify of registry messages

� guarantee of the privacy

� Efficiency� As few as possible extra datas to the end-system

Mobile IP

Mobile IPv4

� Mobile Node (MN)� Mobile system that can change the cell without changing the IP-address

� Home Agent (HA)� Represent the MN in the home network while the MN is in a foreign

network.

� It knows the location of MN.

� Tunneling IP-datagramms to MN

� Foreign Agent (FA)� It is the central processor in a foreign network.

� It relays the tunnelled datagramms to the MN.

� It makes Care-of-Address available to MN.

Mobile IPv4

� Correspondent Node (CN)� The communications partner of the MN

� Home Address (HoA)� The address, where the MN is reachable in the home network

� It administrates the location of the MN, if MN is in a foreign network

� Care-of-Address (CoA)� The address of the current endpoint of the tunnel for the MN

� It shows the current location of MN in the dimension of IP

� FA-CoA: CoA is by the FA

� Co-located CoA: MN gets a CoA from the foreign network

Mobile IPv4

Mobile IPv4

� 3 steps by Mobile IPv4� Agent Discovery

� Agent Advertisement (AA)

� Agent Solicitation (AS)

� Registration� Registration Request

� Registration Reply

� Message Digest

� Tunneling� Forward Tunneling

� Reverse Tunneling

Mobile IPv4

� Agent Discovery� Agent Advertisement

� HA and FA are sending periodically special messages that they exixt in the physically subnetwork

� MN hear the messages and recognize if it is in the home- or foreign-network

� MN get to know a CoA from the messages of the FA

� Agent Solicitation� MN itselves send a request to the FA to start a AA� AS is used if the FA is not sending itselves or MN don‘t want to wait� MN want that the agents answer immediately � MN not receive an Advertising home network

Mobile IPv4

� Registration� MN contact via FA its HA the CoA

� HA authenticate via FA to the MN

� These actions must be secure with an authentification

Mobile IPv4

� Tunneling� Problem

� HA must relays packets to the FA.

� FA has another IP-address like the MN

� Base Solution� The original packet with Header and Payload are used as Payload of the

new IP-packet

� Header of the new IP-packet includes the IP-address of the FA

Mobile IPv4

� Reverse Tunneling

Fast Handover in Mobile IPv4

� Low Latency in Mobile IPv4� Goal

� minimize the time of latency

� Methods:� Supporting by...

� Movement-Detection

� IP-address configuration

� Different modi: � Pre-Registration

� Post-Registration

� Combination

� Forwarding of packets

Fast Handover in Mobile IPv4

Fast Handover in Mobile IPv4

� Pre-Registration

Fast Handover in Mobile IPv4

� Post-Registration

Mobile IPv6

� Many shared features with MIPv4, but they are integrated on the IP Layer

� No need for Foreign Agents (FA)

� Support for route optimization is a fundamental part of the protocol

� Works out-of-the-box

Fast Handover in IPv6

� Fast as in „minimization of the handover latency”

� FH as an extension to the MIPv6

� TCP (Layer 4) should not „realise“ the cell change

� The idea for the MN is to get a new Adress Router (AR) prematurelly to the loss of the old AR

� If FH fails, traditional Handover with paket routing from old AR to new AR

New Messages for MIPv6

� Fast Handover is defined by adding a certain number of new messages between the Access Routers and also between Access Routers and the Mobile Node (MN):

� Router Solicitation for Proxy (RtSolPr): from MN to oldAR� Proxy Router Advertisement (PrRtAdv): from oldAR to MN � Handover Initiate (HI): from oldAR to newAR� Handover Acknowledgement (HAck): from newAR to oldAR� Handover Acknowledgement (HAck): from newAR to oldAR� Fast Binding Acknowledgement (F-BAck): from oldAR to MN � Fast Neighbour Advertisement (F-NA): from MN to newAR

Stateless CoA

From oldAR to newAR

Summary

Questions?

Discussion

� Do you think that we have not enough IP-addresses with IPv4?

� Where is the handling with the Handover better: in IPv4 or in IPv6?