Transcript Presentation Slides: ipv6

Auto Configuration
and
Mobility Options
in IPv6
By: Hitu Malhotra
and Sue Scheckermann
Why change from IPv4 to IPv6?

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Need more addresses: 128-bit address space
(4 times wider in bits than IPv4's 32-bit
address space).
Consideration to Realtimeness: Flowlabel
mechanism
Security
User friendly - “Plug and Play”
User Friendliness

“PLUG AND PLAY”
• literally to plug a node into an IPv6 network
and have it configure to the network without
human interference
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Autoconfiguration
• implementation of the “plug and play”
Autoconfiguration
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STATEFUL:
• A server must maintain status information
about each node and administer that stored data
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STATELESS:
• Mechanism allowing individual nodes to figure
out what their IP configuration should be
without a query to a server that has information
about each node
Dynamic Host Configuration Protocol
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DHCP
• Example of stateful autoconfiguration.
• A client/server protocol where the client queries
servers for configuration parameters.
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Problems
• administration of the list of IP’s
• a server to keep track of addresses in use
DHCPv6
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Combination of stateful and stateless
autoconfiguration.
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Solves the two problems in DCHP using
two IPv6 capabilities:
• Hosts may build a “link local address”.
• Availability of a multicast.
IPv6 Stateless Autoconfiguration
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Steps taken by nodes:
• Figures out own Link-Local Address
• Verify Link-Local address to be unique
• Determine what information is necessary for
configuration
• IP address and/or other configuration info
• Determine where to get that information
• Uses stateless or stateful to get information
Router Advertisements
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Next phase of autoconfiguration.
Routers advertise their availablity, various
link and Internet parameters for
configuration.
Two Flags indicate the type of
autoconfiguration a node should use.
Mobile Networking

Goals:
• To allow IPv6 nodes to move from one IP
subnet to another
• Packets destined to a mobile node will reach
when away from home subnet
Micro to Macro Mobility

Micro-mobility
• communicating from cell to cell (wireless
phones)
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Macro-mobility
• movements of nodes from one network to
another
Home Network
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A permanent address is assigned to mobile
node
• uses this home address like a permanent node
when connected to home network
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Home Agent
• a router that maintains a record of current
“binding” of mobile node and “tunnels” packets
to “care-of address”
Home Agent
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Binding
• record of mobile node’s care-of address and
remaining lifetime of that association
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Tunneling
• path of packet while encapsulated (from home
agent to care-of address)
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Care-of Address
• assigned by foreign network or agent
Foreign Network
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Mobile node listens for availability
• agent advertisement
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Mobile node attaches itself to Foreign
Network
• Assigns a care-of address to mobile node
• may use DHCP to get one
• OR specifies a Foreign Agent
• Uses the same inbound address for all foreign nodes
and distributes the packets
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Sends a message to Home Agent
Routing to a mobile node
Home
Agent
Tunnel
Foreign
Agent
HOST
Mobile
Node
How is this different from IPv4?
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Security
• all packets must be authenticated
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Routing
• IPv4 routing based on network prefix
• IPv6 Routing Header - loose source route
Resources
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RFC’s
• request for comments
• 2462, 2002

IPv6 Clearly Explained by Pete Loshin