MOBILE IP. Mobile networking should not be confused with portable networking Portable networking...
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Transcript of MOBILE IP. Mobile networking should not be confused with portable networking Portable networking...
MOBILE IP
Mobile networking should not be confused with portable networking Portable networking requires connection to same
ISP Portable Networking Technology
Cellular systems Cellular Digital Packet Data (CDPD) 3G
Bluetooth Low cost, short range radio links between mobile
devices Wireless Ethernet (802.11)
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Mobile networking3/50
IP assumes end hosts are in fixed physical locations IP addresses enable IP routing algorithms to get
packets to the correct network Each IP address has network part and host part
This keeps host specific information out of routers DHCP is used to get packets to end hosts in
networks This still assumes a fixed end host
What happens if we move a host between networks?
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Without Mobile IP, devices must tear down and set up connections as they move from location (network) to location (network) They change network so they must change IP
address Mobile users don’t want to know that they are
moving between networks
Internet
IP address A
IP address B
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Mobile IP was developed as a means for transparently dealing with problems of mobile users Enables hosts to stay connected to the Internet regardless of
their location Enables hosts to be tracked without needing to change their
IP address Requires no changes to software of non-mobile hosts/routers Requires addition of some infrastructure Has no geographical limitations Requires no modifications to IP addresses or IP address
format Supports security Could be even more important than physically connected
routing
Mobile IP and its Variants
Mobile IPv4 (MIPv4) MIPv4 Low-Latency Handover for MIPv4 (FMIPv4) Regional Registration for MIPv4 (HMIPv4)
Mobile IPv6 (MIPv6) MIPv6 Fast Handover for MIPv6 (FMIPv6) Hierarchical MIPv6 (HMIPv6)
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IETF RFCs
MIP MIPv4: RFC 3344 (2002) MIPv6: RFC 3775 (2004)
FMIP (Fast Handover for MIP FMIPv6: RFC 4068 (2005)
Fast Handovers for Mobile IPv6 FMIPv4: RFC 4881 (2007)
Low-Latency Handoffs in Mobile IPv4 HMIP (Hierarchical MIP)
HMIPv6: RFC 4140 (2005) Hierarchical Mobile IPv6
HMIPv4: RFC 4857 (2007) Mobile IPv4 Regional Registration
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MIPv4: Overview
MIPv4 Nodes MN (Mobile Node): Host CN (Correspondent Node): Host HA (Home Agent): Router FA (Foreign Agent): Router
MIPv4 Address HoA (Home Address): MN CoA (Care-of-Address): FA
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Home Address (HoA) and Care-of Address (CoA)
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• The home address is permanent• The care-of address changes as the mobile host
moves from one network to another.
14.13.16.9 Care-of ad-dress131.5.24.8 Home ad-dress
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Home Agent (HA) A router with additional functionality Located on home network of MN Does mobility binding of MN’s IP
with its CoA Forwards packets to appropriate
network when MN is away Does this through encapsulation
Foreign Agent (FA) Another router with enhanced
functionality If MN is away from HA the it uses an FA
to send/receive data to/from HA Advertises itself periodically Forward’s MN’s registration request Decapsulates messages for delivery to
MN
Protocols Operation
Agent Discovery (MN FA (CoA)) HA’s and FA’s broadcast their presence on each network to which
they are attached It is possible for a mobile node to solicit agent advertisement to avoid
waiting for an agent to advertise. Beacon messages via ICMP Router Discovery Protocol (IRDP) MN’s listen for advertisement and then initiate registration
Registration to HA (via FA) (MN FA HA) When MN is away, it registers its CoA with its HA Typically through the FA with strongest signal Registration control messages are sent via UDP to destination port
434 Data Transfer Through Tunneling
CN => HA (HoA) => FA (CoA) => MN IP-in-IP Tunneling, ..
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MIPv4: Control & Data Flows
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Mobile IP does not use a new packet type for agent solicitation; it uses the router solicitation packet of ICMP.
(Maintain “Visitor list”)
(Maintain Mobility Binding Table)
Tables maintained on routers
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Mobility Binding Table Maintained on HA of MN Maps MN’s home address
with its current CoA Visitor List
Maintained on FA serving an MN
Maps MN’s home address to its MAC address and HA address
Agent advertisement
MIP does not use a new packet type for agent advertisement; it uses the router advertisement packet of
ICMP, and appends an agent advertisement message.
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Registration request and reply
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Registration request format
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Registration reply format
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The Tunneling18/50
HA encapsulates all packets addressed to MN and forwards them to FA IP tunneling
FA decapsulates all packets addressed to MN and forwards them via hardware address (learned as part of registration process)
NOTE that the MN can perform FA functions if it acquires an IP address eg. via DHCP
Bidirectional communications require tunneling in each direction
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The Mobile Node sends packets using its home IP address effectively maintaining the appearance that it is always on its home network.
Data packets addressed to the Mobile Node are routed to its home network, where the Home Agent now intercepts and tunnels them to the care-of address toward the Mobile Node.
Tunneling has two primary functions: encapsulation of the data packet to reach the tunnel endpoint, and decapsulation when the packet is delivered at that endpoint.
The default tunnel mode is IP Encapsulation within IP Encapsulation Typically, the Mobile Node sends packets to the Foreign Agent, which routes them to their
final destination, the Correspondent Node The above data path is topologically incorrect because it does not reflect the true IP
network source for the data—rather, it reflects the home network of the Mobile Node. Because the packets show the home network as their source inside a foreign network, an
access control list on routers in the network called ingress filtering drops the packets instead of forwarding them.
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A feature called reverse tunneling solves the problem by having the Foreign Agent tunnel packets back to the Home Agent when it receives them from the Mobile Node
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Home Agent (HA)
Remote Agent (RA)
Correspondent node (CN)
Mobile node (MN)
Mobile IP in Ac-tion
Mobile Node moves to remote network
1. MN sends Registration request with its new CoA
3. MN sends Registration response, after validating request and
updating binding table
4. Packets sent to MN from CN are tunneled to RA using binding table
Home Address Care-of-Address
A B
Mobility Binding table
2. Mobile binding created for MN with new CoA
CN is successfully communicating with MN via HA
HA Looks binding table
Home Address = A
CoA = B
The movement of the mobile host
is transparent to
the rest of the Internet.
Key Objective of MIP
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Mobile IPv6 (MIPv6)
MIPv6 = MIPv4 + IPv6 Major Differences from MIPv4
FA in MN No FA for MIPv6
CoA: IP address of MN By DHCPv6 or IPv6 Stateless Auto-Configuration
Route Optimization To solve the “Triangular Routing” Problem Provided by default MN CN
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MIP: Triangular Routing Problem
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MIPv6: Route Optimization
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MIPv6: Binding Update
Binding Update to HA Using IPSEC: MN and HA have a security
association AH (Authentication Header) ESP (Encapsulating Security Payload)
Binding Update to CN Return Routability (RR) procedure
For Security Binding Update (BU) procedure
Route Optimization
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MIPv6: Binding Update
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MIPv6: RR (Return Routability)
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MIPv6: Changes to IPv6
New IPv6 Protocol (Header) Mobility Header: a new IPv6 extension header
To carry MIPv6 Binding Update messages How is in the MIPv4 ?
New Option in Destination Option Header Home Address Option
New Type in Routing Header Type 2 Routing Header
New ICMP Messages ICMP HA Address Discovery Request/Reply ICMP Mobile Prefix Solicitation/ Advertisement
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MIPv6: IPv6 Header
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MIPv6: Mobility Header
A New Extension Header of IPv6 Messages for Return Routability
Home Test Init Message Care-of Test Init Message Home Test Message Care-of Test Message
Messages for Binding Update Binding Update Message Binding Acknowledgement Message Binding Error Message Binding Refresh Request Message
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MIP Extensions
Mobile IPv4 (MIPv4) Low-Latency Handover for MIPv4 (FMIPv4) Regional Registration for MIPv4 (HMIPv4)
Mobile IPv6 (MIPv6) Fast Handover for MIPv6 (FMIPv6) Hierarchical MIPv6 (HMIPv6)
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FMIPv6: Fast Handover for MIPv6
MN
PAR NAR
CN
signaling signaling
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FMIPv6: Operations
Handover Initiation L2 Triggers, RtSolPr, PrRtAdv Between MN and AR
Tunnel Establishment HI (Handover Initiate) and HACK Between PAR and NAR
Packet Forwarding PAR => NAR (data buffering at NAR)
FBU, FBack NAR => MN:
FNA (Fast NA)
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FMIPv6: Operational Flows36/50
HMIPv6: Overview
Motivations Localized (Regional) Mobility Management Hierarchical
MIP: MN HA HMIP: MN MAP HA
MAP: Mobility Anchor Point
IP Address (CoA) RCoA (Regional CoA): in the MAP region LCoA (On-Link CoA): in the AR region
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HMIPv6: Architecture
HA
CN
MAP
AR1 AR2
MN
RCoA
MovementLCoA_1
LCoA_2
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HMIPv6: Operations
MN When entering an AR region in the MAP
domain, it gets LCoA (AR region) and RCoA (MAP region) RCoA does not change in the MAP domain
Local Binding Update (LBU) to MAP Bind LCoA & RCoA to MAP
MAP (Acting as a local HA) Only the RCoA need to be registered with
CN/HA Relay all packets between MN and HA/CN
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HMIPv6: MAP Tunnel (MAP MN)
HA
CN
MAP
AR1 AR2
MN
LCoA MAP RCoA CN Home Addr
Outer header Inner header
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MIP in Real World: 3GPP2 (CDMA)
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MIP in 3GPP2
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PROXY MIPV6 (PMIPV6)“Network-based” Localized Mobility Management
Why Network-based?
Host-based MIPv4/v6 has not been yet deployed that much. Why host-based MIP is not deployed yet?
Too heavy specification for a small terminal RFC 3344 (MIPv4): 99 pages RFC 3775 (MIPv6): 165 pages
Battery problem Waste of air resource
No Stable MIPv4/v6 stack executed in Microsoft Windows OS
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PMIPv6
IETF NETLMM WG Internet Draft
“Proxy Mobile IPv6,” draft-ietf-netlmm-proxymip6-00.txt (2007)
GOAL This protocol is for providing mobility support to any
IPv6 host within a restricted and topologically localized portion of the network and without requiring the host to participate in any mobility related signaling.
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Technical Background Host-based vs. Network-based Mobility
Host-based Mobility Network-based Mobility
AR
HA
Route Update
Movement Movement
HA
Route Update
AR
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Proxy MIPv6 Overview
LMM (Localized Mobility
Management)Domain
MAG1
Host B
Host A
LMA
Proxy Binding Update (PBU)Control message sent out by MAG to LMA to register its correct location
Home NetworkMN’s Home Network (Topological Anchor Point)
Proxy Care of Address (Proxy-CoA)The address of MAG. That will be the tunnel end-point.
IP TunnelA IPinIP tunnel LMA and MAG.
MAG2
LMA: Localized Mobility AgentMAG: Mobile Access Gateway
LMA Address (LMAA)That will be the tunnel entry-point.
MN’s Home Network Prefix (MN-HNP)CAFE:2:/64
MN’s Home Network Prefix (MN-HNP)CAFE:1:/64
MN Home Address (MN-HoA)MN continues to use it as long as it roams within a same domain
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Proxy MIPv6 Overview
No host stack change for IP mobility Avoiding tunneling overhead over the air Re-use of Mobile IPv6
PMIPv6 is based on Mobile IPv6 [RFC3775] Only supports Per-MN-Prefix model
Unique home network prefix assigned for each MN.
The prefix follows the MN.
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Proxy MIPv6 Overview
Overall Procedures1. MN moves and attaches to an access router 2. After authentication, MAG (access router) identifies MN 3. MAG obtains MN’s profile containing the Home
Address ..etc4. MAG sends the Proxy Binding Update to LMA on behalf of
MN5. MAG receives the Proxy Binding Ack. from LMA6. MAG sends Router Advertisements containing MN’s home
network prefix Stateless Case: MN will still configure (or maintain) the same
as its home address. Stateful Case: the network will ensure that it always gets its
home address.
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Proxy MIPv6 Overview
MN MAG
MN-Identifier
AAA Server (Policy Store)
AAA Request
AAA Reply + Policy Profile
DHCPRelayAgent
DHCP Server
MN-IdentifierAccess to a new IP link
LMA
Router Advertisement
Proxy Binding Update
Proxy Binding Ack. (MN Home Prefix)
DHCP Request
DHCP Response
DHCP Request
DHCP Response
Tunnel Setup
This can be omitted when stateless configuration is
used.
MAG emulates the MN’s home
link
In case that profile store does not have
MN Home Prefix
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Proxy MIPv6
Proxy Registration LMA needs to understand the Proxy
Registration. Proxy Binding Update
Proxy Binding Acknowledgement
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Proxy MIPv6
Tunnel Management LMA-MAG tunnel is a shared tunnel among many
MNs. 1:1 relation m:1 relation One tunnel is associated to multiple MNs’ Binding
Caches. Life-time of a tunnel should not be dependent on the
life time of any single BCE.
LMA’s Prefix-based Routing LMA will add prefix routes to MN’s home network
prefix over the tunnel.
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Proxy MIPv6
MAG Operation It emulates the home link for each MN. After the access authentication, MAG will obtain MN’s
profile which contains: MN’s home address MN’s home network prefix LMA address ..etc.
It establishes a IPv6/IPv6 tunnel with the LMA. All the packets from MN are reverse tunneled to its LMA All the packets from the tunnel are routed to MN.
Router Advertisement should be UNICASTed to an MN It will contain MN’s Home Network Prefix (MN-HNP)
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Proxy MIPv6
MN Operation Any MN is just a IPv6 host with its protocol
operation consistent with the base IPv6 specification. All aspects of Neighbor Discovery Protocol will
not change. When MN attaches to a new AR, it receives
a Router Advertisement message from the AR with its home prefix.
Throughout the PMIP domain, MN using DHCP procedure or in stateless address configuration mode, will obtain the same home address.
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Proxy MIPv6
Data Transport LMA-MAG Tunneling/Reverse Tunneling
MN LMAMAG CN
MN sends a packet to CNMAG forwards to LMA
LMA sends to CN
CN sends packet to MNLMA forwards to MAG
MAG sends to MN
IPv6 header (src=MAG_ADDR, dst=LMA_ADDR)
IPv6 header (src=MN_ADDR, dst=CN_ADDR)
Payload
IPv6 header (src=LMA_ADDR, dst=MAG_ADDR)
IPv6 header (src=CN_ADDR, dst=MN_ADDR)
Paylaod
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