IPv6 DHCP

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IPv6 DHCP

• By Santosh Yadav
• IIT Kanpur

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IPv6 Dynamic Host Configuration Protocol
Overview

• Evolution Of DHCPv6
• DHCPv6 Concepts
• Installation
• Configuration

3
Evolution Of DHCPv6

• To boot the machines in a LAN, needs lot of
  network parameters to be configured in each
  machine.
• In order to avoid this manual process, all the
  network parameters are put in a server and when a
  machine in LAN is booting, it will contact the
  server for the configuration parameters. This is
  called BOOTP server. Later it is extended to DHCP
  with additional features.
• Generally called DHCP

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Evolution Of DHCPv6
IP configuration in IPV6 is carried out by IPV6
auto-configuration

• IPv6 auto-configuration
• Stateless
• nodes configure addresses themselves with
• information from routers (if available)
• no managed addresses
• Stateful
• nodes use DHCPv6 to obtain addresses.
• Duplicate address detection (DAD) used to avoid
• duplicated addresses

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Dhcpv6 Concepts

• What is DHCPv6 ?
• The Dynamic Host Configuration Protocol for IPv6
• (DHCP) enables DHCP servers to pass
  configuration
• parameters such as IPv6 network addresses to
  IPv6
• nodes.
• DHCPv6 protocol Released in RFC 3315
• This protocol is a stateful counterpart to "IPv6
  Stateless
• Address Autoconfiguration" (RFC 2462).
• Used separately or concurrently with the latter
  to obtain
• configuration parameters.

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Dhcpv6 Concepts

• DHCPv6 Versus DHCPv4
• The following lists the main differences between
  DHCPv4 and DHCPv6
• Unlike DHCPv4, IPv6 address allocation in DHCPv6
  is
• handled using a message option.
• The message types, such as DHCPDISCOVER and
• DHCPOFFER supported by DHCPv4 are removed in
• DHCPv6. Instead, DHCPv6 servers are located
  by a client
• SOLICIT message followed by a server ADVERTISE
  message
• Unlike DHCPv4 clients, DHCPv6 clients can
  request multiple
• IPv6 addresses.

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Dhcpv6 Concepts
Why we need dhcpv6 ?

• A method of providing stateful IPv6 address
  configuration/assignment
• Also provides other network information
• DNS servers
• NIS information

• DHCP allows centralized control and
• auditing of IP address assignments
• Central point of control for resources
• Dynamic DNS updates
• More security versus stateless

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Dhcpv6 Concepts
DHCPv6 Basic Message Format
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0
1 2 3 4 5 6 7
SOLICIT ADVERTISE REQUEST CONFIRM
RENEW REBIND REPLY
RELEASE DECLINE RECONFIGURE
INFORMATION-REQUEST RELAY-FORW RELAY-REPL
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Message Type Option
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Dhcpv6 Concepts
DHCP Messages

• Messages exchanged using UDP
• Client port udp/546
• Server Port udp/547
• Client uses Link-Local address or addresses
  determined using other methods to transmit and
  receive DHCP messages.
• Server receives messages from clients using a
  reserved, Link-Scoped multicast address.

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Dhcpv6 Concepts
DHCP Multicast Addresses

• All_DHCP_Relay_Agents_and_Servers
• Link-scoped multicast address used by a client to
  communicate with on-link relay agents and servers
• FF0212
• All_DHCP_Servers
• Site-scoped multicast address used by a relay
  agent to communicate with servers
• FF0513

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Dhcpv6 Concepts
DHCPv6 option format and base option
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0
1 2 3 4 5 6 7
Client Identifier Server Identifier
Identity Association for Non-temporary
Addresses Identity Association for Temporary
Addresses IA Address Option Request
Preference Elapsed Time Relay Message
Authentication Server Unicast Status Code
Rapid Commit User Class Vendor Class
Vendor-specific Information Interface-Id
Reconfigure Message Reconfigure Accept
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Dhcpv6 Concepts
DHCP Unique Identifer (DUID)

• Each DHCP client and server has a DUID. DHCP
  servers use DUIDs to identify clients for the
  selection of configuration parameters and in
  client Identity Associations.
• Unique across all clients and servers
• Should not change over time (if possible)
• Must be lt 128 octets long

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Dhcpv6 Concepts
Identity Association

• An identity association (IA) is a construct
  through which a server and client can identify,
  group, and manage a set of related IP addresses.
• Client must associate at least one distinct IA
  with each
• network interface requesting assignment of IP
• addresses from DHCP server (IAID)
• Must be associated with exactly one interface
• Must be consistent across restarts by the client

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DHCPv6 working
DHCP client
DHCP server B
SOLICIT
DHCP server A
T I M E
ADVERTISE
ADVERTISE
REQUEST
Client select one advertise server B
REPLY
Client Now use address and parameter for lifetime
Client renew life time
RENEW
REPLY
Client releases address when shutting down
RELEASE
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Dhcpv6 Concepts

• Dhcpv6 operation
• Client sends messages to link-local multicast
  address
• Server unicasts response to client
• Information-Request / Reply - provide client
  configuration
• information but no addresses
• Confirm / Reply - assist in determining whether
  client moved
• Reconfigure - allow servers to initiate a client
  reconfiguration
• Basic client/server authentication capabilities
  in base
• standard.
• DHCP Unique Identifier (DUID) used to identify
  clients
• servers
• Identity Association ID (IAID) used to identify
  a collection of
• addresses
• Relay Agents used when server not on-link
• Relay Agents may be chained

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Ongoing Project

• Previously DHCPv6 v1.001and now DHCPv6 2.001
  available for the HP-UX 11i v1 and HP-UX 11i v2
  operating systems http/docs.hp.com
• Dibbler is a portable DHCPv6 implementation on
  Linux 2.4/2.6 and Windows XP and Windows 2003.
• This project was started as master thesis by
  Tomasz Mrugalski and Marek Senderski of Computer
  Science faculty on Gdansk University of
  Technology.
• http//klub.com.pl/dhcpv6/
• Project UNIX name dhcpv6
• Operating System All POSIX
  (Linux/BSD/UNIX-like OSes), Linux
• http//dhcpv6.sourceforge.net/

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Installation

• Dhcpv6 server
• Update with dhcpv6-0.10-11_FC3.i386.rpm using
• rpm -U dhcpv6-0.10-11_FC3.i386.rpm
• Create a database directory
• mkdir /var/db/dhcpv6
• Copy sample server configuration file
• cp dhcp6s.conf /etc/dhcp6s.conf
• Start the server daemon using
• dhcp6s dDf eth0

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Installation

• Dhcpv6 client
• Update with dhcpv6_client-0.10-11_FC3.i386.rpm
  using
• rpm -U dhcpv6_client-0.10-11_FC3.i386.r
  pm
• Copy sample client configuration file
• cp dhcp6c.conf /etc/dhcp6c.conf
• Start the client daemon using
• dhcp6c dDf eth0

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Configuration
In Fedora core 3 following files are configured
Server configuration /etc/sysconfig/dhcp6s /et
c/dhcp6s.conf
File /etc/sysconfig/dhcp6s Specify the
interface for dhcp6s DHCP6SIFeth0

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Configuration
Server configuration...
File /etc/dhcp6s.conf interface eth0
server-preference 255 renew-time
60 rebind-time 90 prefer-life-time
130 valid-life-time 200 allow
rapid-commit link BBB pool range
20010E30140224 to 20010E3014022ffff/64
prefix 20010E301402/48

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Configuration
In Fedora core 3 following files are configured
Client configuration /etc/sysconfig/network-sc
ripts/ifcfg-eth0 /etc/dhcp6c.conf
File /etc/sysconfig/network-scripts/ifcfg-eth0
IPV6INITyes DHCP6Cyes

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Configuration
client configuration...
File /etc/dhcp6c.conf
interface eth0 information-only send
rapid-commit request prefix-delegation request
temp-address address
20010E301402196563456/64

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Testing
Start the server daemon in debug mode in
foreground dhcp6s dDf eth0 Restart the network
service of client service network restart See
the address assignment ifconfig
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Thank you for your attention
Any Question?
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IPv6 Multicasting

• By Kaveri Bhaumik
• IIT Kanpur

27
Topics covered are

• Definition of multicasting
• Multicast addresses
• Comparison between IPv4 multicasting IPv6
  multicasting
• VideoLAN Client (VLC) media player
• Advantage of using multicasting in VLC
• Installing VLC
• UDP Streaming With VLC using the GUI

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Definition of Multicasting

• Multicast is communication between a single
  sender and multiple receivers on a network.
• Together with anycast and unicast, multicast is
  one of the packet types in the Internet Protocol
  Version 6 (IPv6).

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Graphical Representation Of Multicasting
Sending Entity
Receiving Entity
Service Provider
Receiving Entity
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IPv6 ADDRESSING

• There are three types of addresses
• Unicast An identifier for a single interface.
  
• Anycast An identifier for a set of interfaces
  and is delivered to one of the interfaces
  identified by that address.
• Multicast An identifier for a set of interfaces
  and is delivered to all interfaces identified by
  that address.
• Note -gt There are no broadcast addresses in
  IPv6, their function being superseded by
  multicast addresses.

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Multicast addresses

• Multicast addresses always start with (xx is the
  scope value)
• ffxy
• Multicast addresses format
• 8 4 4
  112 bits
• ------------------------------------------
  ------------------- 11111111flgsscop
  group ID
• -----------------------------------------
  -------------------
• Multicast addresses are split into scopes and
  types

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Multicast addresses format

• 11111111 at the start of the address identifies
  the address as being a multicast address.
• 
  - - - -
• flgs is a set of 4 flags 0 0 0
  T
• 
  - - - -
• The high-order 3 flags are reserved.
• T 0 indicates a permanently-assigned
  ("well-known") multicast address, assigned by the
  global internet numbering authority.
• T 1 indicates a non-permanently-assig
  ned ("transient") multicast address.

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Multicast scopes

• ffx1 node-local
• ffx2 link-local
• ffx5 site-local
• ffx8 organization-local
• ffxe global scope
• others are reserved

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Multicast types

• All Nodes Address
• ID 1h, addresses all hosts on the local
  node (ff010000001) or the connected link
  (ff020000001).
• All Routers Address
• ID 2h, addresses all routers on the local
  node (ff010000002), on the connected link
  (ff020000002), or on the local site
  (ff050000002).

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Comparison between IPv4 multicasting IPv6
multicasting

• Although the basic notion of multicasting is
  common to IPv4 and IPv6, several new
  characteristics are introduced in IPv6
  multicasting.
• In IPv4,multicasting was extension of the basic
  specification, while specifications of IPv6
  require that all IPv6 nodes support multicasting.
• IPv6 explicitly limits the scope of a multicast
  address by using a fixed address field, whereas
  the scope was specified using TTL (Time to Live)
  of a multicast packet in IPv4.

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Comparison

• In IPv4, multicast tunnels were introduced to
  deploy multicasting .In IPv6,all routers should
  be multicast-capable, which means that we do not
  have to use multicast tunnels to deploy IPv6
  multicasting.
• IPv4 multicasting use unicast addresses to
  identify a network interface. However, this is
  not suitable for IPv6,as an IPv6-capable node may
  assign multiple addresses on a single interface,
  which tends to cause a configuration mismatch. In
  IPv6 ,to identify the interface the user must use
  specified interface index.

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Implementation of multicasting

• We have practically tested multicasting over IPv6
  in IITK .
• Muticasting in IPv6 has also been tested across
  the router using the global scope address .
• For multicast testing we have used VideoLan
  Client media player which is a freeware.

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VideoLAN Client (VLC) media player

• VLC - the cross-platform media player and
  streaming server.
• VLC is a multimedia player for various audio and
  video formats (MPEG-1, MPEG-2, MPEG-4, DivX, mp3,
  ogg, ...) as well as DVDs, VCDs, and various
  streaming protocols.
• It can also be used as a server to stream in
  unicast or multicast in IPv4 or IPv6 on a
  high-bandwidth network.

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Advantage of using multicasting in VLC

• Problems encountered using unicast or
  broadcast are
• with unicast, when a lot of clients want to
  receive the stream, the network interface of the
  server becomes saturated.So the number of clients
  is very limited, especially when the stream is
  big.
• with broadcast, the machines that do not want to
  receive the stream are polluted and some devices
  do not like to receive huge broadcasts. If you
  want to send several streams at the same time,
  the network becomes oversaturated.

42
Advantage of using multicasting in VLC

• With multicast, the packets are sent on the
  network to a multicast IP group which is
  designated by its IP address.
• The machines can join or leave a multicast group
  by sending a request to the network. The request
  is usually sent by the kernel of the operating
  system.
• The VLC takes care of asking the kernel of the
  operating system to send the join request.
• It is possible for one client to belong to
  several groups.

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Showing a scenario giving example of multicasting

• Server(vlc) Network
  Clients(vlc)
• stream --------------gt ff1e1
  ---------------gt client n1
• 
  -------------gt client n2
• Server(vlc) Network
  Clients(vlc)
• 
  lt--------------- client n3 join
• 
  join ff1e1
• Server(vlc) Network
  Clients(vlc)
• 
  -------------gt client n1
• stream --------------gt ff1e1
  ---------------gt client n2
• 
  -------------gt client n3

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Scenario of multicasting

• Server(vlc) Network
  Clients(vlc)
• 
  lt--------------- client n1 leave
• 
  leave ff1e1
• Server(vlc) Network
  Clients(vlc)
• stream ---------------gt ff1e1
  ---------------gt client n2
• 
  -------------gt client n3
• 
  
  

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Installing VLC

• For Fedora Core 3
• Download the VLC Binaries packages
• vlc-binary.tar.gz
• For Windows
• Download the self-extracting package
• vlc-0.8.1-win32.exe
• Above packages are available in
  http//www.videolan.org/

46
To run the VLC

• Type the following command to run VLC
• vlc
• This is the VLC media player

47
UDP Streaming With VLCusing the GUI

• Server Send the Data
• Select File Open File, and Browse to select a
  file.
• Select the Stream output checkbox, then the
  Settings button this opens a Stream Output
  window.
• Output Methods
• For multicasting, select UDP and write
  following
• address ff1e and port
  1234
• Select the checkbox Play locally

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UDP Streaming Stream Output
window
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UDP Streaming

• Client Receive the Data
• Open VLC on the receiving PC.
• Select File Open Network Stream.
• To join the session of multicast as sent by
• the server do the following
• Select UDP/RTP multicast and write
• address ff1e and port
  1234
• Click the OK button, and the VLC display window
  should open.

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Reference

• Further information about VLC can be obtained
  from
• http//www.videolan.org/
• THANK YOU FOR YOUR ATTENTION
• Any Questions?

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