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IPv6 Autoconfig full process from initial configuration of IPV6 Node. Refreshment of IPv6 Addresses using RA or DHCPv6. How to keep your home config everywhere you go and only logout when you want to, not when you move to a new access point.
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© 2011 Fred Bovy. IPv6AutoConfig—2-1
IPv6 Clients Autoconfiguration The whole process In-Depth fully explained!
Version 2.0
© 2011 Fred Bovy. IPv6AutoConfig—2-2
This presentation gives an in-depth explanation of the IPv6 Autoconfiguration process. It covers all the possible combinations to configure and to maintain automatically the IPv6 nodes using all the possible options currently available. This presentation focuses on IPv6 Autoconfiguration but it also introduces the Mobile IPv6 based applications. At the end of the presentation you will fully understand how the IPv6 nodes initially get configured and how the network configuration may be changed over time if needed. You will also understand the benefits of running Mobile IPv6. And you will deserve a good coffee break!
Presentation Objectives
© 2011 Fred Bovy. IPv6AutoConfig—2-3
Fred Bovy § 15 years experience in IPv6
– IPv6 Forum Certified Gold Engineer – IPv6 Forum Certified Gold Trainer
§ 20+ years experience with CISCO, TCP/IP – 15 years CCIE #3013 (it was only R&S in 1997!) – 18 years CCSI #33517 since 1994 (it was #95003) – 7 years Cisco IOS IPv6 Software Engineer (NSSTG Group) – 3 years Cisco Network Consultant (CA Group)
§ 12+ years experience in MPLS
Meet me on: – Twitter: FredBovy – Skype: FredericBovy – Blogs: http://www.fredbovy.com/Go46/ – LinkedIn, owner of 3 IPv6 Groups – Email me: [email protected]
About the Author
© 2011 Fred Bovy. IPv6AutoConfig—2-4
IPv6 Autoconfiguration
Introduction to Autoconfiguration
© 2011 Fred Bovy. IPv6AutoConfig—2-5
§ With Autoconfiguration, a network node can configure itself completely and modify its configuration anytime needed.
Network Addresses, default route, DNS and Others Servers addresses, domain name, Dynamic DNS Updates
§ How Autoconfiguration is used: For Offices or Campuses: - Renumbering if a new prefix must be used for a site or a company - For privacy, the Interface ID can be changed with a random value every day - With Mobile IPv6 enabled, support the Mobile users. They keep using their office home addresses
while they are roaming.
Roaming devices without Mobile IPv6 - Autoconfigured is used to get addresses for each visited access network - Application must be restarted each time as sockets are differents - This is how MOST devices are currently operating !
Mobile IPv6: Mobile Routers (NEMO), MANET, Sensors (6LowPAN) - The home Address is the only address known by the end-user Application - A new Address (COA) acquired by Autoconfig is used for each visited network (Wifi, 3G) - Because the home address is the same, the same socket is used, there is no interruption, no
need to restart the applications
What is Autoconfiguration ?
© 2011 Fred Bovy. IPv6AutoConfig—2-6
Autoconfiguration (SLAAC) on Linux! Autoconfiguration is Enabled by default on most platforms but Linux ! For Linux use sysctl -w or add in the /etc/sysctl.conf the following configuration:
To Enable Autoconfig use:
This is only about Stateless Address Autoconfiguration (SLAAC) and has nothing to do with Mobile IPv6. We will introduce Mobile IPv6 later in this presentation
© 2011 Fred Bovy. IPv6AutoConfig—2-7
Autoconfig Addresses in Tentative Mode Autoconfiguration First Step is the Tentative Mode to verify the IPv6 Addresses which are configured or could be configured on the interface IPV6 INTERFACE IS GOING UP…
§ First, the Link local address is generated and tested to enable the interface for IPv6 § The Link Local address is verified with Duplicate Address Detection (DAD) § The Link-Local address MUST be valid or Autoconfig exits and the Interface is disabled for
IPv6 § Once the Link-Local passed DAD, the IPv6 Interface is Up and other addresses are also
generated from the RA or allocated by DHCPv6 and validated by DAD
Valid
Preferred Deprecated
Preferred Lifetime
Valid Lifetime
Invalid Tentative
© 2011 Fred Bovy. IPv6AutoConfig—2-8
Autoconfig Address is in Preferred state n The « NORMAL » state for an address in production. n The address verified by DAD can be used to send and receive unicast traffic. n The address can be used for new connections or by existing one n The Preferred Lifetime is determined by the field Preferred Lifetime included
in the RA Prefix Information or the Preferred-Lifetime Option in the DHCPv6
As long as the derived Address is refreshed with RA Prefixes or the allocated address is reniewed by DHCPv6, the address state will remain Preferred!
Valid
Preferred Deprecated
Preferred Lifetime Valid Lifetime
Invalid Tentative
© 2011 Fred Bovy. IPv6AutoConfig—2-9
Autoconfig Address is in Deprecated state The Address was not refreshed by a RA or DHCPv6 for Preferred timer… n Can be used for Renumbering, during the transition to a NEW prefix n New connection SHOULD not use this address n Existing communications SHOULD still be able to use this address as source. « An implementation MAY prevent any new communication from using a deprecated address, but system management MUST have the ability to disable such a facility, and the facility MUST be disabled by default. » RFC4862!
Valid
Preferred Deprecated
Preferred Lifetime Valid Lifetime
Invalid Tentative
© 2011 Fred Bovy. IPv6AutoConfig—2-10
Autoconfig Address is in Valid state The address can be used to send and received unicast traffic Valid state = Preferred + Deprecated The Valid Lifetime is determined by the field Valid Lifetime included in the RA Prefix Information or the Valid-Lifetime Option in the DHCPv6 IA Address
Valid
Preferred Deprecated
Preferred Lifetime
Valid Lifetime
Invalid Tentative
© 2011 Fred Bovy. IPv6AutoConfig—2-11
Autoconfig Address is in Invalid State The address cannot be used to send or receive traffic The address reaches the Invalid state when the Valid Lifetime has
expired
« An address (and its association with an interface) becomes invalid when its valid lifetime expires. An invalid address MUST NOT be used as a source address in outgoing communications and MUST NOT be recognized as a destination on a receiving interface. » RFC4862!
Valid
Preferred Deprecated
Preferred Lifetime
Valid Lifetime
Invalid Tentative
© 2011 Fred Bovy. IPv6AutoConfig—2-12
IPv6 Autoconfiguration
IPv6 Interface is going up
© 2011 Fred Bovy. IPv6AutoConfig—2-13
Client initializes the Link-Local Address Derive the link-local
addressFE80::[Interface ID]
Send multicast NS. Destination address derived from the link-
local
NA received ? Stop
Initialize the link-local
Send RS
RA Received ? Use DHCPv6
Set Hop Limit, Reachable Time,
Retrans Timer, MTU
Prefix Information present ?
A
B
Managed Address
Configuration Flag = 1 ?
Other Configuration
Flag = 1 ?Use DHCPv6
Stop
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
© 2011 Fred Bovy. IPv6AutoConfig—2-14
1. IPv6 Interface is going up 1. Initialize and check the Link-Local Address 2. Send a Router Solicitation (RS) message to get the
Autoconfiguration info from the Router Advertizements (RA) 3. Initialize and validate default Parameters and other Addresses
derived from the Prefixes learned from the Router Advertizement (RAs)
4. Check if DHCPv6 must be used for Addresses ? Other configurations ?
To A’s Solicited node address FF02::1:FF1E:8329
fe80::202:b3ff:fe1e:8329
© 2011 Fred Bovy. IPv6AutoConfig—2-15
Initialization of the Link-Local Address Workstation picks up a link-local address § i.e. fe80::202:b3ff:fe1e:8329 EUI-64 § Using prefix fe80::/10 and build the 64 bit Interface ID from EUI-64 format § May be generated Cryptographically if SeND CGA is used (RFC3972)
Workstation performs Duplicate Address Detection (DAD) § Sends NS to its own Neighbor Solicited Node Multicast Address !
– FF02::1:FF00:0/104 + last 24 bits = ff02::1:ff1:8329 § Expect no answer or the address is a duplicated (DUP)
IF DAD Fails for the the Link-Local address the IPv6 Intf is disabled ! 3 attempts if CGA(RFC3972)
© 2011 Fred Bovy. IPv6AutoConfig—2-16
Ubuntu performing DAD (NS) Captured
IPv6 Source address is ::
IPv6 Neighbor Solicitation
IPv6 Router Solicitation message to the All-Routers ff02::2
Dst address is the solicited node multicast address: ff02::1:ff30:3386
Neighbor Solicitation
© 2011 Fred Bovy. IPv6AutoConfig—2-17
Client Send Request and get Autoconf parameters Derive the link-local
addressFE80::[Interface ID]
Send multicast NS. Destination address derived from the link-
local
NA received ? Stop
Initialize the link-local
Send RS
RA Received ? Use DHCPv6
Set Hop Limit, Reachable Time,
Retrans Timer, MTU
Prefix Information present ?
A
B
Managed Address
Configuration Flag = 1 ?
Other Configuration
Flag = 1 ?Use DHCPv6
Stop
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
© 2011 Fred Bovy. IPv6AutoConfig—2-18
2. IPv6 Intf is Going Up!
1. Link-Local Address initialized and unique ! 2. Send a Router Solicitation (RS) message to get the
Autoconfiguration info from the Router Advertizements (RA) 3. Initialize and validate default Parameters and other Addresses
derived from the Prefixes learned from the Router Advertizement (RAs)
4. if Check DHCPv6 must be used for Addresses ? Other conffigurations ?
© 2011 Fred Bovy. IPv6AutoConfig—2-19
2. Clients request Autoconfig Information The client issues a Router Solicitation (RS) using its link-local as source Address to the all-routers multicast destination address to request all the parameters needed for autoconfiguration: § The default Hop Limit, the Link MTU, a default route… § The Prefixes to used for autoconfiguration § DHCPv6 must be used and what for? Addresses or Other Configurations?
If NO Response to the RS, then try a DHCPv6 Solicit and EXIT Autoconfig!!!
All-Routers: FF02::2
No Router
© 2011 Fred Bovy. IPv6AutoConfig—2-20
To Accept RA on Linux clients For Linux, it must be configured with sysctl command or
editing the /etc/sysctl.conf file. Use sysctl -w or add in the /etc/sysctl.conf the following config:
To Accept the RA use:
© 2011 Fred Bovy. IPv6AutoConfig—2-21
ISP 6RD RG RA Router Solicitation and Router Advertisement Router Advertisement sent to the All-IPv6 Nodes multicast ff02::1
Router Lifetime: 1800 secondes
Don’t modify the Reachable Timer and the Retrans timer
Prefix Option: 2a01:e35:2f26:d340::/64 On-Link Bit Flag Set Autonomous Bit Flag Set Valid Lifetime: 86400 sec Preferred Lifetime: 86400 sec
DNS Servers Option: 2a01:e00::1 2a01:e00::2
MTU Option: 1480 bytes
Source Link Layer Address Option f4:ca:e5:44:10:ef
© 2011 Fred Bovy. IPv6AutoConfig—2-22
If no RA Received, clients run DHCPv6
Solicit Dst:All_DHCP_Relay_Agents_and_Servers (FF02::1:2)
Request Dst: Server Dst:All_DHCP_Relay_Agents_and_Servers (FF02::1:2) Src: Client Link-local address
Relay-reply Dst: Client Link-local address
Src: Server Link-local address
DHCPv6 Client
DHCPv6 Server
DHCPv6 Relay!
Relay-Forward to All_DHCP_Servers (FF05::1:3)
Relay-reply
Advertize
Relay-Forward to All_DHCP_Servers (FF05::1:3)
Reply
If no RA Received, Autoconfiguration ends here !
© 2011 Fred Bovy. IPv6AutoConfig—2-23
IPv6 is not IPv4
DO NOT SUPPRESS the RA on LAN intf to force DHCPv6 By default the RA are enabled on a LAN interface and disabled on a Serial Point to Point. RAs are very useful to provide many other important IPv6 parameters like a default route, link MTU, the default Hop-Limit or the Neighbor Unreachability (NUD) parameters and more. If no RA is received, the client tries DHCPv6 and Exits Autoconfiguration!
For the clients to use DHCPv6:
Set the Managed Addr Config and Other Config flags.
Suppressing the RA will not convert IPv6 to IPv4
DHCPv6 cannot provide a default route !
© 2011 Fred Bovy. IPv6AutoConfig—2-24
Client is looping on the prefixes lists to autoconfigure new Addresses
A
Take the first prefix information
On-Link Flag = 1 ?
Add the prefix to the list
Autonomous Flag = 1 ?
Derive the Stateless Prefixe:[interface ID]
Send NS to the derived address
NA Received ?
Other prefixes to process
Yes
No
Initialise the Stateless address
Go to next prefix
BNo
No
Yes Do not initialize the stateless
address
No
Yes
Yes
© 2011 Fred Bovy. IPv6AutoConfig—2-25
IPv6 Interface is going Up! 1. Link-Local Address Validated, IPv6 Intf is UP! 2. A Router Solicitation (RS) message was sent and a Router
Advertizements (RA) was Received 3. Initialize and validate the default Parameters and other
Addresses derived from the Prefixes learned from the Router Advertizement (RAs)
4. Check if DHCPv6 must be used for Addresses ? Other configurations ?
© 2011 Fred Bovy. IPv6AutoConfig—2-26
Router Advertisements (RA) information § The Router is a candidate for default Route?
The Lifetime timers is how long a Router will remain a valid next hop without any refresh. If Lifetime = 0, the router cannot be used as a default route if Lifetime > 0, the Link-local IPv6 Address must be used as a default next hop. The RA also contains a Router Preference: Low, Medium or High. The router MAC Address is also provided in the SLLA Option.
§ Other Important Configuration: Hop Limit and MTU for the Link Reachable Timer and Retransmit interval used by NUD DNS Servers Addresses in the DNS Option (RFC6106) A List of zero or more prefix(es)
§ Should we also use of DHCPv6 for more Autoconfig? Managed and Other Config Flags
Warning: RFC6104. Rogue RA !!!
© 2011 Fred Bovy. IPv6AutoConfig—2-27
RA on Cisco Router - show ipv6 routers hote#show ipv6 routers
Router FE80::2038:148E:B9DF:FD6D on FastEthernet0/0, last update 2 min
Hops 64, Lifetime 1800 sec, AddrFlag=0, OtherFlag=0, MTU=1500
HomeAgentFlag=0, Preference=Medium
Reachable time 0 (unspecified), Retransmit time 0 (unspecified)
Prefix 2001::/64 onlink autoconfig
Valid lifetime 2592000, preferred lifetime 604800
IMPORTANT REMARKS: The Router Lifetime applies only to the router's usefulness as a default router; it does not apply to information contained in other message fields or options. Options that need time limits for their information include their own lifetime fields.
A router which can’t be used as a default router or shutting down sends a RA with Lifetime=0 (0) Unspecified does not mean that the parameter must set to zero but it means « DO NOT CHANGE »
whatever value which is preconfigured on the node
© 2011 Fred Bovy. IPv6AutoConfig—2-28
Client process the Optional RA Prefix(es) List In each RA there may be a list of Prefixes which can
be used by SLAAC Each Prefix comes with: § The Length of the Prefix § 2 bits or Flags: the On-Link bit and the Autonomous bit
– Both flags MUST be SET for the Prefix to be used by SLAAC A full Stateless 128 bits address can be derived from the prefix adding an Interface ID
– The 64 bits Interface ID can be built: - From the MAC Address: EUI-64 format or - With a Random Number if Privacy Extension is configured (RFC4941)
§ 2 Timers: the Preferred Timers and the Valid Timers. – This is how long the addresses derived from the RA advertized prefix if learned from
SLAAC will remain in the Preferred and in the Valid States. These timers are also managed when the addresses are allocated by a DHCPv6 Stateful Server.
– The Timers can be reset by the periodic RA, in this case, the unsolicited RA transmission interval must be set to refresh the SLAAC derived addreses before they get deprecated or invalid. The Timers can also be refreshed by DHCPv6 protocol.
– Statically configured IPv6 addresses have Infinite Preferred and Valid Timers.
© 2011 Fred Bovy. IPv6AutoConfig—2-29
Accept Prefixes from RA on Linux clients
© 2011 Fred Bovy. IPv6AutoConfig—2-30
The Client processes each Prefix of the List The Prefix is selected for SLAAC if both On-Link and Autonomous bits are set, then
Use EUI-64: Interface ID is derived from the MAC Address
Mac Address 48 bit X=1 Unique X=0 Not Unique
00 90 59 02 E0 F9
00 90 59 02 E0 F9 FF FE
000000X0
Use Privacy Extension (RFC4941): Interface ID is selected randomly
On Windows netsh interface ipv6 set privacy=enabled
On Mac OS X sysctl net.inet6.ip6.use_tempaddr=1 On Linux sysctl net.ip6.conf.if.use_tempaddr=2
OR
© 2011 Fred Bovy. IPv6AutoConfig—2-31
Client checks if DHCPv6 can be used Derive the link-local
addressFE80::[Interface ID]
Send multicast NS. Destination address derived from the link-
local
NA received ? Stop
Initialize the link-local
Send RS
RA Received ? Use DHCPv6
Set Hop Limit, Reachable Time,
Retrans Timer, MTU
Prefix Information present ?
A
B
Managed Address
Configuration Flag = 1 ?
Other Configuration
Flag = 1 ?Use DHCPv6
Stop
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
© 2011 Fred Bovy. IPv6AutoConfig—2-32
IPv6 Interface is Going Up! 1. Initialize and validate the Link-Local Address. IPv6 Intf Up! 2. Router Solicitation (RS) message Sent and the Router
Advertizements (RA) received 3. Initialize and validate default Parameters and other Addresses
derived from the Prefixes learned from the Router Advertizement (RAs)
4. Check if DHCPv6 must be used for Addresses ? Other configurations ?
© 2011 Fred Bovy. IPv6AutoConfig—2-33
Clients check if DHCPv6 MUST be used In each RA there are 2 flags to advertize the use of DHCPv6! Managed Address Configuration Flag The Managed Address or M flag tells the clients to use DHCPv6 to configure IPv6 Address(es) Actually when the M bit is set, DHCPv6 is used to request all the available DHCPv6 configuration other information and the O is redundant Cisco Interface config « ipv6 nd managed-config-flag »
Other Configuration Flag The Other or O flag tells the clients to use DHCPv6 to configure everything but the IPv6 addresses. In this case the IPv6 Address(es) must be configured using SLAAC or manually Cisco interface config « ipv6 nd other-config-flag »
DHCPv6 Cannot be used to configure a default route! Some drafts exist but still no RFC!
© 2011 Fred Bovy. IPv6AutoConfig—2-34
IPv6 Autoconfiguration Modes Stateless Address Autoconfiguration § NO DHCPv6, all the configuration is loaded with RA or or PPP
Statefull DHCPv6 Autoconfiguration § DHCPv6 provides addresses and other parameters (DNS, domaine
name, SIP…) § The Managed and the Other Config flags are set
Stateless DHCPv6 Autoconfiguration § SLAAC is used for address autoconfiguration § DHCPv6 for the other informations (DNS, Domain Name)
DHCPv6 Prefix Delegation § The CPE which is a DHCPv6-PD Client receives a block of address (IPv6
Subnet) from the SP, the DHCPv6-PD Server. This block can be subnetted to configure multiple LAN interfaces. The CPE DHCPv6-PD Client can also be a DHCPv6 Stateless server for instance.
© 2011 Fred Bovy. IPv6AutoConfig—2-35
Stateless Address AutoConfig Signalisation IPv6 routers signal the use of DHCPv6, if both bit are not cleared (default) then DHCPv6 is not used. § M flag « Managed Adress Configuration » is set when address and network parameters configuration are available from DHCPv6. Must be configured on the routers. – no ipv6 nd Managed-config-flag
§ O flag « Other Statefull Configuration » is set when Other parameters configuration must be found from DHCPv6 – no ipv6 nd Other-config-flag
© 2011 Fred Bovy. IPv6AutoConfig—2-36
Stateless Address AutoConfiguration n RFC 4862, IPv6 Stateless Address Autoconfiguration n RS/RA To request prefixes available to build addresses n DAD to test the new addresses n NO DHCPv6 Server required!
Autoconfiguration is configurable on Linux!
© 2011 Fred Bovy. IPv6AutoConfig—2-37
Stateful DHCPv6 Autoconfig Signalisation IPv6 routers signal the use of DHCPv6. Not M and O bits must be set in the RA. § M flag « Managed Adress Configuration » is set when address and network parameters configuration are available from DHCPv6. Must be configured on the routers. ipv6 nd Managed-config-flag
§ O flag « Other Statefull Configuration » is set when Other parameters configuration must be found from DHCPv6 ipv6 nd Other-config-flag
© 2011 Fred Bovy. IPv6AutoConfig—2-38
Statefull DHCPv6 Autoconfiguration
DHCPv6 with Rapid Commit
Address and Other parameters are configured from DHCPv6
© 2011 Fred Bovy. IPv6AutoConfig—2-39
Stateless DHCPv6 Autoconfig Signalisation
IPv6 Routers signal the DHCPv6 utilization § M bit = 0 « Managed Adress Configuration » to use
SLAAC for address autoconfiguration no ipv6 nd managed-config-flag
§ O bit = 1 « Other Statefull Configuration » to use DHCPv6 for Other parameter configuration ipv6 nd Other-config-flag
Address is configured by SLAAC
Other parameters are then requested to the DHCPv6 Server
© 2011 Fred Bovy. IPv6AutoConfig—2-40
Stateless DHCPv6 Autoconfiguration
DHCPv6 with Rapid Commit
Address configuration from the prefix received in the RA (SLAAC)
Other parameters are given by a DHCPv6 Server
© 2011 Fred Bovy. IPv6AutoConfig—2-41
© Frédéric Bovy 41
DHCP Prefix Delegation DHCPv6 PD Server allocates a block of addresses for the DHCPv6-PD Client The block received by the client is then subnetted to configure each interface
© 2011 Fred Bovy. IPv6AutoConfig—2-42
DHCPv6-PD Client and DHCPv6 Stateless Server
DHCP ND/DHCP AAA
1. CPE Sends DHCP Solicit with ORO = PD
2. PE Sends RADIUS Request for the User
3. RADIUS Responds with User’s Prefix(es)
4. PE Sends DHCP REPLY with Prefix Delegation Options
5. CPE Configures Addresses from The Prefix on Its Downstream Interfaces, and Sends an RA. O-bit Is Set to On
6. Host Configures Addresses Based on the Prefixes Received in the RA. As the O-bit Is on, It Sends a DHCP Information-request Message, with an ORO = DNS 7. CPE Sends a DHCP REPLY
Containing Request Options
Host
ISP Provisioning System
E0 E1 PE
ISP
DHCP Client DHCP Server
CPE DHCPv6-PD Server DHCPv6-PD Client
DHCPv6 Lite Server
© 2011 Fred Bovy. IPv6AutoConfig—2-43
6RD Service Providers RG Autoconfig
• RG=Residential Gateway, BR=Border Router • Native dual-stack IPv4/IPv6 in the home or office • Simple, stateless, automatic IPv6-in-IPv4 encap and decap functions • IPv6 traffic automatically follows IPv4 routing between CPE and BR • BRs placed at IPv6 edge, addressed via anycast for load-balancing and
resiliency • RG Config can be pushed via TR-69, DHCP Option 212, PPP IPCP • Standardized in RFC 5969
RG
6rd
BR
IPv4
IPv4 + IPv6 Core
IPv4 + IPv6 IPv4 + IPv6 IPv4 + IPv6
6rd
© 2011 Fred Bovy. IPv6AutoConfig—2-44
IPv6 Autoconfiguration
Autoconfigured Address Refreshment
© 2011 Fred Bovy. IPv6AutoConfig—2-45
Remember the Preferred state ! n This is the « NORMAL » state for an address in production.
Each address has the two timers constantly updated from the system clock: Preferred and Valid As long as the derived Address is refreshed with RA Prefixes or the allocated address is reniewed by DHCPv6, the address state will remain Preferred!
Valid
Preferred Deprecated
Preferred Lifetime Valid Lifetime
Invalid Tentative
© 2011 Fred Bovy. IPv6AutoConfig—2-46
When the Interface has been started and is used by IPv6, each address which has been autoconfigured only has a limited Preferred and Valid Lifetime. • Addresses derived from a Prefix advertized by a prefix received in a RA must be refreshed by another RA annoucing the same prefix with same or different Preferred and Valid Lifetime • Addresses which are allocated by DHCPv6 also have a Valid and a Preferred Lifetime which must also be reset by DHCPv6 Reniew.
Autoconfigured addresses have a finite Valid and Preferred Lifetime
© 2011 Fred Bovy. IPv6AutoConfig—2-47
Refreshing the SLAAC Addresses Timers • An address which has been derived from a RA must
be refreshed by new RAs advertizing the same prefix • The RA Interval must be consistent with the Preferred
and the Valid Timers for the addresses to be refreshed in time
ipv6 nd ra-interval 200 seconds by default ipv6 nd ra-lifetime 1800 seconds or 30 minutes default ipv6 nd managed-config-flag ipv6 nd other-config-flag ipv6 nd prefix <prefix/mask> [Valid] [Preferred]
• To Be used by SLAAC: - The On-Link and Autonomous Bits Must be Set - If Preferred Lifetime > Valid lifetime, ignore the Prefix
Information option. A node MAY wish to LOG a system management ERROR in this case….
© 2011 Fred Bovy. IPv6AutoConfig—2-48
Update the Address Preferred and Valid Timers The preferred lifetime of each address is reset to the Preferred Lifetime in the received advertisement. The Valid Lifetime depends on RemainingLifetime, the remaining time to the valid lifetime expiration of the previously autoconfigured address. 1. If the received Valid Lifetime is greater than 2 hours or greater than
RemainingLifetime, set the valid lifetime of the corresponding address to the advertised Valid Lifetime.
2. If RemainingLifetime is less than or equal to 2 hours, ignore the Prefix Information option with regards to the valid lifetime.
if SeND is used, the Advertizes Valid Lifetime is used to update Valid Lifetime.
3. Otherwise, reset the valid lifetime of the corresponding address to 2 hours.
© 2011 Fred Bovy. IPv6AutoConfig—2-49
SLAAC Prefix Refreshed and Timers Updated by RA
1400
1600
200s
1900 2100
Preferred and Valid Timers at the Workstations
IPv6
RA are sent every 200 seconds +/-jitter Preferred: 1600-200 = 1400 secondsValid = 2100 - 200 = 1900 seconds
2001:db8:4:1::1/64initial timers:Preferred:1800, Valid: 2100
Just before receiving RAPreference:1400, Valid: 1900
After Receiving the RAPreference: 1800, Valid: 2100
2001:db8:4:1::2/64Preferred:1400, Valid:1900
Same Principle than other Workstation
SLAAC Timers just Before receiving the RA:Preferred: 1600-200 = 1400 secondsValid = 2100 - 200 = 1900 seconds
After receiving the RA:Preferred is reset to 1600 secondsValid was 1900 seconds, RemainingLifetime= 1900Received Valid = 2100 is greater than RemainingLifetime=1900So Valid Lifetime is reset to Received Valid Lifetime = 2100
Prefix: 2001:db8:4:1::/64On-Link, AutonomousPreferred:1800, Valid:2100
RA Interval default: 200 secondsRA Lifetime default: 1800 seconds
Unsolicited Periodic RA
© 2011 Fred Bovy. IPv6AutoConfig—2-50
Addresses are coded as DHCPv6 Options • IA Address Option (IADDR)
- The IA Address option is used to specify IPv6 addresses
associated with an IA_NA (Non Temporary) or an IA_TA (Temporary).
- The IA Address (IADDR) option must be encapsulated in the Options field of an IA_NA or IA_TA option.
- The Options field encapsulates those options that are specific to this address. preferred-lifetime The preferred lifetime for the IPv6 address in the option, expressed in units of seconds.
valid-lifetime The valid lifetime for the IPv6 address in the option, expressed in units of seconds.
Theses Timers are also in DHCPv6 Addresses
© 2011 Fred Bovy. IPv6AutoConfig—2-51
Address Refreshed by DHCPv6-PD Renew
© 2011 Fred Bovy. IPv6AutoConfig—2-52
IPv6 Autoconfiguration
Renumbering
© 2011 Fred Bovy. IPv6AutoConfig—2-53
Principle of Renumbering for IPv6 Renumbering can be performed thanks to RA or DHCPv6 1. Old prefix is announced with Preferred Lifetime very
small or null and the new prefix with a normal Preferred Lifetime
2. Hosts will have two prefixes 3. Addresses built from the old prefix will be deprecated 4. New connections use the new prefix 5. After some time, all the remaining connections will be
set on the new prefix 6. Router only announces the new prefix 7. Old prefix will be invalid
© 2011 Fred Bovy. IPv6AutoConfig—2-54
© Frédéric Bovy 54
Renumbering Scenario using RA Routers Configuration interface Ethernet0
ipv6 nd prefix 2001:db8:cafe:1::/64 43200 0
ipv6 nd prefix 2001:db8:cafe:2::/64 43200 43200
RA Preferred Prefix: 2001:db8:cafe:2::/64 Deprecated Prefix: 2001:db8:cafe:1::/64
Host Preferred address: 2001:db8:cafe:2:1:4567:9f0:1 Deprecated address: 2001:db8:cafe:1:4567:9f0:1
Valid
Preferred
© 2011 Fred Bovy. IPv6AutoConfig—2-55
Autoconfiguration
Mobile IPv6: keep your home address everywhere you go, keep always online and only logout when you want to not when you move to another location!
© 2011 Fred Bovy. IPv6AutoConfig—2-56
Mobile IPv6 for dummies… Without Mobile IPv6, everytime you visit a new access network, your network applications must be restarted using the new socket because the IPv6 Source Address has changed! With Mobile IPv6, the mobile nodes (MN) can travel and visit access networks but the applications still believe that packets are originated from and sent to the Home Network Address.
On the Home Network, the Router must be a Home Agent (HA).
At the begining it intercepts and forwards traffic from the Correspondant Node (CN) to the Mobile Node (MN).
Once communication has started, it is possible to setup a direct tunnel
between the MN and the CN. This is Route Optimization. New with IPv6, impossible with IPv4!
© 2011 Fred Bovy. IPv6AutoConfig—2-57
Why MIPv6 never restart any session? § The MN can roam from subnet to subnet getting a new IPv6 address for
each visited network but the same home network address is always presented to the application! No need to restart any session
§ The CN always sends packets to the Home Network Address and packets received by the CN are always originated from the Home Network Address!...No Magic, this is managed by Mobile IPv6 at the Network Layer so it is transparent for the Transport and Application layers
© 2011 Fred Bovy. IPv6AutoConfig—2-58
§ For MAC OS X check KAME Free BSD – KAME Mobile IPv6 How To
§ http://www.kame.net/newsletter/20031007/
§ Linux – Project NATISBAD – The KAME project ported to Linux
§ http://natisbad.org/MIPv6/#racoon
§ Windows – Very limited support with Windows 7 – Only CN Mode w/o Route Optimization
netsh interface ipv6 set mobility correspondentnode=enabled
Mobile IPv6 is supported on Linux and Free BSD
© 2011 Fred Bovy. IPv6AutoConfig—2-59
Most Important Terminology
Home Agent The router which forward the traffic to the Mobile Node (MN) when the us is at home!
Mobile Node The roaming user node.
Home Address All the packets from the Mobile Node (MN) received by the Corresponding Node (CN) come from this source address. All the packets sent to the Mobile Node (MN) from the Corresponding Node (CN) are sent to this destination address.
Home Link The link where the mobile node is permanently attached.
Care-Of-Address The temporary address on the visited network.
Correspondant Node The fixed node (not mobile) communicating with the Mobile Node (MN).
© 2011 Fred Bovy. IPv6AutoConfig—2-60
§ MN must acquire its Care-of-Address (CoA) § Autoconfiguration with SLAAC or DHCPv6…as usual!
Mobile Node visits a new access network
Mobile Node acquires its Care of Address from SLAAC or DHCPv6
© 2011 Fred Bovy. IPv6AutoConfig—2-61
§ The Mobile Node (MN) registers its CoA with the Home Agent The Home Agent is Automatically discovered using an Anycast Reserved address.
§ MIPv6 Signaling uses an IPv6 Mobility Option in an IPSec ESP protected tunnel ( )
§ An IPv6 in IPv6 IPSec Tunnel is setup between the Mobile Node and the Home Agent
Mobile Node (MN) initializes its new location
Mobile Node
1
2
© 2011 Fred Bovy. IPv6AutoConfig—2-62
Why the Applications don’t need to restart their Transport Connection (i.e TCP)?
Mobile Node
CN IPv6 @
In Dst MN IPv6 Home @
CN IPv6 @
Src @ Dst @
MN IPv6 CoA
HA IPv6 @
MN IPv6 Home @
Out Src Out Dst In Src 1) The HA replaces the COA src addr with the the MN IPv6 Home Address.
CN IPv6 @
MN IPv6 Home @
Src @ Dst @
HA IPv6 @ MN IPv6 CoA
CN IPv6 @
MN IPv6 Home @
Out Src Out Dst In Src In Dst 2) The HA replaces the HA dst addr with the the MN IPv6 Home Address
HA
© 2011 Fred Bovy. IPv6AutoConfig—2-63
1. The Corresponding Node (CN) must support Mobile IPv6 with Route Optimization
2. The Mobile Node (MN) initiates this by sending a Binding Update to the Corresponding Node (CN)
3. The Corresponding Node (CN) sends Keygen Tokens to the Mobile Node (MN) at both its CoA and its Home Address. If the MN receives both, it has proven its identity to the CN! It receives a Binding Ack and the Tunnel setup!
Can we build a direct tunnel to bypass the HA?
Mobile Node
MN proves to the CN that it receives the Keygen Tokens
Binding Update
Binding Ack
© 2011 Fred Bovy. IPv6AutoConfig—2-64
Why the CN Application receives packets of the MN originated from the MN Home Network Address?
Mobile Node
MN IPv6 CoA
CN IPv6 @
MN IPv6 Home @
Src @ Dst @ Dst Opt
The CN replaces the MN IPv6 CoA with the IPv6 Home @ from the Destination Option: Datagram comes from the MN
© 2011 Fred Bovy. IPv6AutoConfig—2-65
Why the MN Application receives a packet with the Home Network Addr as the dst Addr?
Mobile Node
The MN replaces the MN IPv6 CoA with the MN IPv6 Home @ from the Routing Option: Datagram is sent to the MN Home @
CN IPv6 @
MN IPv6 CoA
MN IPv6 Home @
Src @ Dst @ Routing
© 2011 Fred Bovy. IPv6AutoConfig—2-66
§ Proxy Mobile IPv6 (PMIPv6) for LTE and 4G § Mobile Router or Nemo
– RFC3963: NEMO Basic Support Protocol – A router is moving with all its networks and connected hosts – RFC5555: Mobile IPv6 Support for Dual Stack Hosts and
Routers – UMIP Project on Linux
– http://natisbad.org/MIPv6/#umip
§ Ad Hoc dynamic mobile networks or Manet – Nodes discover their neighbors dynamically and join the
network
§ Wireless Sensors Networks (6LoWPAN)
Mobile IPv6 Applications
© 2011 Fred Bovy. IPv6AutoConfig—2-67
Proxy Mobile IPv6 introduced with LTE 1. The MN enters the PMIPv6
domain and attach to an access-link.
2. The MAG verifies the MN Identity and Authorizations.
3. If OK, the MAG helps the MN to get all the configuration: address, default gateway,…
4. The MN considers the PMIPv6 domain as a link
Authentication
The LMA provides the Mobile IPv6 HA function
IPv6 Network
Local Mobility Anchor(LMA1)
Mobile NodeMN1
Mobile Access
Gateway (MAG1)
Mobile Access
Gateway (MAG3)
Mobile Access
Gateway (MAG2)
Local Mobility Anchor(LMA2)
Mobile NodeMN2
To offload the Mobile IPv6 Signaling and IPSec Protection complexity from the Smartphones to a Network device
© 2011 Fred Bovy. IPv6AutoConfig—2-68
Local Mobility Anchor(LMA1)
Mobile NodeMN1
Mobile Access
Gateway (MAG1)
Proxy MIPv6 converts ND requests to MIPv6 Signaling
1. The MN sends a RS (Router Solicitation) to the MAG. 2. For updating the LMA about the MN location, the MAG sends a
PBU (Proxy Binding Update) to the MN’s LMA. 3. The LMA sends a PBA (Proxy Binding Acknowledgement)
including the MN home network prefixes. It creates the Binding Cache entry and sets up its endpoint of the bi-directional tunnel to the MAG.
4. The MAG sends a RA: Router Advertisement to the MN. The MAG can emulate the MN’s Home Link
5. The MN can be configured using SLAAC or DHCPv6
n PBA/PBU Signaling must be protected with IPSec !
n Data Protection is Optional
RS
PBU
PBA including the MN home network prefixe(s)
RA
1
2
3
4
The LMA provides the Mobile IPv6 HA function
© 2011 Fred Bovy. IPv6AutoConfig—2-69
§ Mobile Router can receive a block of addresses from DHCPv6-PD § The Mobile Router Can be a Smartphone to provide access Internet
via 4G to local nodes with WiFi or Bluetooth access.
The Mobile Router: Nemo
Dual Stack avec DSMIPv6
IPv6 InternetHome Network
Home Agent
Corresponding node
WLAN
3G Network
NEMORouter
IPv4 IPv6
Bluetooth or WiFi
© 2011 Fred Bovy. IPv6AutoConfig—2-70
With MANET, the nodes discover automatically configure their neighbors and build a dynamic Network To manage the neighbors a node can use:
– OSPFv3 – EIGRP
What if these nodes have sensors?
Mobile Ad Hoc Networking: Manet
Wireless Uplink
© 2011 Fred Bovy. IPv6AutoConfig—2-71
Wireless Sensors Networks (6LoWPAN) The Network of Sensors can be built dynamically using Dynamic MANET On-demand for 6LoWPAN (DYMO-low).
Possible Applications: • Localized weather monitoring • Structural Health monitoring (Earthquake prone areas) • Battlefield troop detection, movement • Intelligent Transportation Systems (ITS) • Green app: Building environment management – Lights, HVAC, Security Access, smart power outlets, etc. – Building demo - ~20% MRC cost savings
This concludes IPv6 Autoconfiguration In-depth Presentation Fred Bovy IPv6 Forum Gold Certified Engineer IPv6 Forum Gold Certified Trainer CISCO 15 years CCIE #3013 CISCO 18 years CCSI #33517 (before was #95003) Meet me on Twitter: FredBovy Skype: FredericBovy Blog: http://www.fredbovy.com/Go46 Email: [email protected]
Thank you for attending!