Mobile IPv6 PresentationElmic
Systems
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Mobile IPv6 Scenarios
Network “push”: accept incoming VoIP packet-switched phone calls on your global scope IPv6 (unchanging) home address, regardless of where you are physically attached to the network
Roaming between different L2 technologies: seamlessly switch between different network interfaces (I.e. move from 3G wireless or GPRS to 802.11b) while preserving your application connectivity
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Roaming without Mobile IP
Without Mobile IP, devices must tear down and set up connections as they move from location to location
Internet
Roaming with Mobile IP
Mobile IPv6 allows an IPv6 host to leave its home subnet, while transparently maintaining all its connections and remaining reachable to the rest of the Internet
Internet
How it works
Mobile IPv6 identifies each node by its unchanging global home address, regardless of its current point of attachment to the Internet
While a mobile node is away from home it sends information about its current location (I.e. primary care-of address) to a home agent on its home link
The home agent intercepts packets addressed to the mobile node’s home address and tunnels them to the mobile node’s current location (I.e. primary care-of address)
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Mobile IPv6
Triangular Routing
address is associated with
Home
Network
The transition to IPv6 has been designed so that all nodes to IPv6 are not required to be upgraded at the same time. Many transition mechanisms have been designed that enable smooth integration of IPv4 and IPv6. Other mechanisms are available for compatibility where IPv4 nodes can talk to IPv6 nodes and vice-versa. All these mechanisms can be applied to different situations and cases.
The graphic shows one example of a transition and integration mechanism. The 6to4 routers automatically encapsulate the IPv6 traffic inside IPv4 packets. This mechanism is described later in more detail.
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Mobile IPv6
Route Optimization
address is associated with
Mobile Node
Home
Network
The transition to IPv6 has been designed so that all nodes to IPv6 are not required to be upgraded at the same time. Many transition mechanisms have been designed that enable smooth integration of IPv4 and IPv6. Other mechanisms are available for compatibility where IPv4 nodes can talk to IPv6 nodes and vice-versa. All these mechanisms can be applied to different situations and cases.
The graphic shows one example of a transition and integration mechanism. The 6to4 routers automatically encapsulate the IPv6 traffic inside IPv4 packets. This mechanism is described later in more detail.
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Elmic Mobile IPv6
draft-ietf-mobileip-ipv6-22.txt
draft-ietf-mobileip-mipv6-ha-ipsec-05.txt
At least an order of magnitude smaller than embedded Linux
Route optimization can be excluded at compile-time, further reducing code size; can also disable per application socket
MN Binding Update List and CN Binding Cache are fully integrated with existing Voyager TCP/IP performance optimizations
Includes Wi-Fi example device driver (Intersil PRISM 2.5)
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Elmic Correspondent Node
Compile-time macro limits size of Binding Cache
Optimized nonce and Kcn management
Optimized Binding Cache maintenance
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Elmic Mobile Node
Fully integrated with Elmic’s IPsec/IKE
Which is not a BITS implementation, rather it is tightly integrated with Voyager TCP/IP for optimal performance
Home addresses are configured by user application on special virtual home interface
Keeps them separate from care-of addresses, with regard to source address selection & packet routing
Supports Mobile Prefix Solicitation/Advertisement messages
Supports Dynamic Home Agent Address Discovery
Implements MIPv6 Generic Movement Detection with support for L2 triggers
Optional support for Eager Cell Switching
Supports Key Management Mobility Capability (K) bit in Binding Update and Binding Acknowledgement messages
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Mobile Node Public APIs
tf6MnGetHomeAgentAddress performs Dynamic Home Agent Address Discovery for a home agent on home network
tf6MnStartMobileIp is called to specify the home agent address and start Mobile IPv6 movement detection.
tf6MnRegisterBinding creates mobility binding between a specified care-of address and a specified home address, and then initiates registration of that binding with home agent
tf6MnMoveNotify is called to notify the MN of L2 triggers (L2 and L3 handovers), as well as of a change of network interface (I.e. switch from GPRS to 802.11b)
The application can be notified of various MN events, such as status of home registration, movement detection events, etc.
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Mobile Node State Machine
16 events, 9 states to manage CN registration (BUL entry)
Some of the state machine design was in an earlier MIPv6 draft, but removed in draft 18. This state machine can be found in open source implementations of MIPv6 (such as KAME). However, it combines MN home registration (with HA) and CN registration (for route optimization) in the same state machine.
We have two separate state machines for mobility bindings:
One for managing home registration
The other for managing CN registration (BUL entry)
Result: an easier to understand and more robust implementation
Don’t use separate state machine to manage Return Routability
Instead this is part of our CN registration (BUL entry) state machine
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'Disabled' State
Special state ‘disabled’, we transition a CN registration (BUL entry) to when we determine a specific CN does not support route optimization. To avoid DoS attacks, once we’ve successfully registered binding with specific CN, we can never enter ‘disabled’ state, so the transition to ‘disabled’ can only occur on initial registration.
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Libero State Machine Design
We used free state machine design tool Libero to do our MN state machine design. It is available at:
http://www.imatix.com/html/libero/index.htm
Libero, an excellent design tool, supports customizable code generation
Implemented code generation “schema” to output state machine design in HTML format, suitable for inclusion in our design documentation.
Comes with schemas for C and AT&T “dot” formats to generate state machine transition diagrams and other programming languages.
Atoosa Rezai (AR)
Integration with
Wireless TCP
RFC-2018 + FACK (Forward Acknowledgement), RFC-2414, RFC-2481, RFC-2581, RFC-3042
When a mobile node comes back on-link it notifies TCP of L2 handover. TCP then performs the recovery:
TCP was sending data, and was trying to retransmit: if TCP had gone into retransmission timeout during off-link condition, then upon coming back on-link TCP immediately retransmits one segment of unacknowledged data. This enables TCP to not be penalized (as much) by exponential backoff on retransmissions. Note, when TCP (re)transmits packets while MN is off-link, these packets are not queued but instead are discarded – this avoids MN queuing up duplicates of retransmitted packets to send once it is back on-link.
TCP receiver (peer TCP was sending data): the peer might have tried to send data while we were off-link, and we did not receive that data. So, TCP upon coming back on-link sends 3 duplicate ACKs to activate remote Fast Retransmit algorithm.
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Elmic Features and Benefits
Code has small footprint, low latency, efficient memory usage
Runs with (or) without RTOS
Optimized for even small industrial control devices not needing any RTOS
Platform and RTOS Independent
Extensive internal and external testing of the stack
Assures a quality stack product
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Elmic Emerging Products
Elmic Product Portfolio
TCP/IP v4 and IPv4/v6 Dual Stack
IPSec/IKE
Wireless Medical
communication Device
In Conclusion