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Detecting Wireless Network Attachment. February 14, 2006. Author: Heikki Mahkonen Supervisor: Professor Raimo Kantola Instructor: M.Sc. Tero Kauppinen. Contents. Objectives and Research Methods IPv6 Information Configuration Mobility Protocols Mobility Management Movement Detection - PowerPoint PPT Presentation
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Slide titleIn CAPITALS
50 pt
Slide subtitle 32 pt
Detecting Wireless Network Attachment
February 14, 2006
Author: Heikki MahkonenSupervisor: Professor Raimo KantolaInstructor: M.Sc. Tero Kauppinen
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2006-01-122 (19)
Contents
Objectives and Research Methods IPv6 Information Configuration Mobility Protocols
– Mobility Management– Movement Detection
Detecting Wireless Network Attachment Simulation Environment Results and Conclusions
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Objectives and Research Methods
Objective was to evaluate different network attachment detection methods and how they are suited for wireless network environments.
Provide a simulation environment for further mobility protocol research for Ericsson Research, Finland (NomadicLab).
The first objective was conducted as a literature study. The simulation environment was implemented as a part of this
Master’s thesis. Different movement detection mechanisms were simulated and
their behavior compared and analyzed to produce results and conclusions.
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IPv6 Information Configuration IPv6 Neighbor Discovery (RFC 2461)
– Message exchange– Data structures
Router list Prefix list Neighbour cache Destination cache
Parameter Discovery– Router Advertisement– Router Solicitation
Stateless and stateful address autoconfiguration.– Stateless Address Autoconfiguration (SAA) (RFC 2462) – Dynamic Host Configuration Protocol for IPv6 (DHCPv6) (RFC 3315)
Duplicate Address Detection (DAD)– Neighbor Solicitation– Neighbor Advertisement
Neighbor Unreachability Detection (NUD)– Neighbor Solicitation– Neighbor Advertisement
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IPv6 Information Configuration Router Advertisement and Solicitation Messages
Type=134 Code=0 ChecksumCHL M O Res. Router Lifetime
Reachable TimeRetrans Timer
Options...
Type=134 Code=0 ChecksumReserved
Options...
Router Advertisement Router Solicitation
Prefix Information Option
Type=3 L ALength Prefix Len.Valid LifetimePreferred Lifetime
Prefix
Res.
Reserved2
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IPv6 Information ConfigurationMobile Host
IPv6 ND Access RouterMH Stateful AddressAutoconfiguration
MH Stateless AddressAutoconfiguration
1. Router Advertisement
* [forever]
RA retrans.timer (3-16 sec.)
2. Router Solicitation3. Router AdvertisementRS retrans.
timer (1 sec.)
4. RA received* [3 or if RA received]
5a. [M:=No] Configure Address
5b. [M:=Yes] Configure address
6a. Address
6b. Address
8. [O:=Yes] Configure IPv6 information
9. IPv6 Information
7a. Neighbour Solicitation (DAD)
7b. Neighbour Solicitation (DAD)
* [number of prefixes in RA]
10. Check reachability 11. Neighbour Solicitation12. Neighbour Advertisement
Parameter Discovery
Address Autoconfiguration
DuplicateAddressDetection
NeighbourUnreachableDetection
DAD timer
DAD timer
RA received
RA received
RA delaytimer (0 – 0.5 sec.)
RS delaytimer (0 - 1 sec.)
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Mobility Protocols Mobility protocols work on network and upper OSI
reference model layers. Different mobility protocols for different OSI reference
model layers.
Data-link layerPhysical layer
HIP Mobility
Sockets
Transport layer
Network layer
Session layer
Application layer SIP Mobility
Session LayerMobility
SCTP Mobility
MIPv6
TCP Mobility UDP Mobility
UpperLayers
LowerLayers
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Mobility Protocols Mobility protocols provide a mobile host a way to retain
Internet connectivity while changing attachment point to the Internet.
Mobility for a mobile host is achieved by providing distinction between location and identity of the mobile host.
Mobility protocol can be divided into three parts– location update– location management– movement detection
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Mobility Protocols
Internet AccessNetwork
MH
WLAN Foreign Link
WLAN Home Link
CH
HA
Router
Router
Data
Data BU BA
Location Update in MIPv6.
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Mobility Protocols
Internet AccessNetwork
MH
WLAN Foreign Link
WLAN Home Link
CH
BUBA
DataData
Router
HA
Location Management in MIPv6.
Data
Router
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Mobility Protocols Movement detection signals the attachment changes of the mobile host to the mobility protocol. Two movement detection mechanisms are defined to give comparison for the DNAv6 optimized movement detection mechanisms in the simulations. Basic Movement Detection
– Bases on the data structures provided by the IPv6 ND.– Uses the signaling provided by the IPv6 ND.
Link-layer Notification Enhanced Movement Detection– Uses the Link-layer notifications to trigger IPv6 information configuration.– Needs ”link up” and ”link down” notifications from network interface to work.
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Mobility ProtocolsMobile Host
IPv6 ND Access RouterMobile Host AddressAutoconfiguration
1. Router Advertisement(from a new router)
Mobile HostIPv6 ND NC
Mobile HostRAI Timer
5. Check reachability 6. Neighbour Solicitation7. Neighbour Advertisement
9. Check reachability 10. Neighbour Solicitation
4. Create NC elememt
NC timer
ND retrans timer
8. NC element reachable
25. NC element unreachable
3. Start RAI timer
RAI timer
23. Remove addresses
11. Purge IPv6information
13. Neighbour Solicitation14. Neighbour Advertisement15. Access router reachable
RAI timer 17. Neighbour Solicitation
ND retrans timer 21. Purge IPv6information
NC timer
12. RAI timer expired
16. RAI timer expired
2. Select default router
22. Purge IPv6 information
26. Stop RAI timer
19. Update address lifetimes
18. Router Advertisement(from the same router)
20. Restart RAI timer
24. Purge routerand prefix list
27. Select default router
21. Update routerand prefix list timers
28. Select default router
30. Neighbour Advertisement29. Neighbour Solicitation
31. Signal movement
Mobile HostMobility Protocol
Basic Movement Detection
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Mobility ProtocolsMobile Host
IPv6 ND Access RouterMobile Host AddressAutoconfiguration
4. Router Advertisement
12. Remove addresses
5. Select default router
11. Purge IPv6 information
9. Update address lifetimes
8. Router Advertisement(from the same router)
13. Purge routerand prefix list
14. Select default router
10. Update routerand prefix list timers
1. Link Up
3. Router Solicitation
6. Link Down
7. Purge IPv6 information
15. Select default router
17. Neighbour Advertisement16. Neighbour Solicitation
Mobile HostMobility Protocol
18. Signal movement
RA delaytimer (0 – 0.5 sec.)
2. Neighbour Solicitation (DAD)
Link-layer Enhanced Detection
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Detecting Wireless Network Attachment IETF DNA (Detecting Network Attachment) Working
Group.“The purpose of the DNA working group is to define standards track and BCP documents that allow hosts to detect their IP layer configuration and connectivity status quickly, proposing some optimization to the current specifications that would allow a host to reconfigure its IPv6 layer faster than today.” (IETF DNA Working Group)
Contributions:– RFC 4135: Goals of Detecting Network Attachment in IPv6.– Draft: BCP for Hosts.– Draft: BCP for Routers.– Draft: Link-layer Event Notifications for DNA.– Draft: Fast Router Discovery with L2 Support.– Draft: DNA with unmodified routers: Prefixlist based approach.– Draft: Detecting Network Attachment in IPv6 Networks (DNAv6)
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Detecting Wireless Network Attachment DNAv6 Problems
– Link identification issues.– Delay Issues.– Issues with wireless network environments.
DNAv6 Goals– The DNA solution must detect whether the mobile host must configure the IPv6 information on a newly attached link.– The delay for identifying the link and possible IPv6 information configuration must be minimized.– The DNA solution must not falsely assume that the link change has occurred and initiate a re-configuration of the IPv6 information.– The DNA solution must keep the signaling needed for the detection process at minimum.– The DNA solution must reuse the existing signaling mechanisms.– The DNA solution must use the link-local signaling for the detection procedure and there must be no need for global IPv6 addresses for the detection process.– The DNA solution must also function on links where secure ND.– The security vulnerabilities in the IPv6 information configuration must not be increased by the DNA solution.– There must be appropriate backward compatibility with hosts and access routers using the DNA solution and with hosts and access routers not utilizing the DNA solutions.– The DNA solution must take into account the characteristics of the wireless network environments.
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Detecting Wireless Network Attachment Best Current Practices for Hosts and Routers
– Configuration instructions for hosts and routers.– Does not provide/demand any implementation add-ons to
existing protocols. Fast Router Discovery (FRD) with L2 Support
– Specifies a way to disscover access routers as fast as possible in the WLAN access networks.
– Uses a L2 support in the WLAN AP.– The ”link up” notifications sent to the access router or the
AP caches and proxies the RA messages to mobile hosts.
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Detecting Wireless Network Attachment DNAv6 specifies a optimal solutions for the link identification and fast
routter discovery. Satisfies all the goals specified in the RFC 4135. Defines three data structures.
– For router: ”DNARouterList” ”DNARouterPrefixList”
– For mobile host: ”DNAHostPrefixList”
Landmark prefix– The prefix which the mobile host is currently using.
Link identifier prefix– Access routers choose the numerically smallest prefix to be used as the
LinkID prefix.– At least this prefix must be added to every RA message.
Fast Router Advertisement– ”DNARouterList” has a router tokens (SHA-1 hash of the access router
address).– Source address in the RS message is hashed and compared to the router
tokens (XOR) to get the ”ranking” of the router.– Router with ranking zero will answer first.– RA delay is the ”rankin” multiplied by RASeparation (20) milliseconds.
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Detecting Wireless Network Attachment DNAv6 uses two flags in the RA message.
– D flag indicates DNAv6 compatibility.– C flag indicates that the RA message carries complete set of network prefixes.
DNAv6 specifies two new options to RS and RA messages.
Type=134 Code=0 ChecksumCHL M O Router Lifetime
Reachable TimeRetrans Timer
Options...
Router Advertisement
Landmark Prefix Option
Type Y NLength Prefix Len.Reserved
Landmark Prefix
Res.
D C R
Learned Prefix Option
Type Length Prefix L. 1
Prefix 1
Prefix L. 2... Prefix L. N Padding
Prefix 2
Prefix N
...
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Detecting Wireless Network Attachment DNAv6 operation for an access router.
Access Router Other AccessRouters on link Mobile Host
1. Bootstrap
Access RouterDNARouterList
Access RouterDNARouterPrefixList
1. Router Advertisement (D=0, C=0)2. Router Solicitation3. Router Advertisement (D=1, C=1)4. Store router
5. Store prefix
6. Router Advertisement (D=1, C=1)
8. Update prefix
7. Update router
9. Router Solicitation
10. Router Advertisement (D=1, C=1)
11. Router Solicitation (without LMPO)
17. Router Advertisement (D=1, C=1)
15. Get ranking
16. Ranking
13. Get learned prefixes
14. Learned prefix option
18. Router Solicitation (with LMPO)
27. Router Advertisement (D=1, C=1 &LMPO)
25. Get ranking
26. Ranking
19. Check landmark prefix
23. Get learned prefixes
24. Learned prefix option
Access RouterIPv6 ND
22. Result
21. Check landmark prefix
20. Result
RA delaytimer
RA delaytimer
RA delaytimer
RA delaytimer
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Detecting Wireless Network Attachment DNAv6 operation for a mobile host.
Mobile HostIPv6 ND Access RouterMobile Host Address
Autoconfiguration
5. Router Advertisement (D=1,C=1 & to unicast)
8. Select default router
1. Link Up (establish)
4. Router Solicitation (with TSLLAO)
Mobile HostMobility Protocol
RA delaytimer
3. Neighbour Solicitation (DAD)
12. Router Advertisement(D=1,C=1, with LMPO & to unicast)
14. Identify the link
9. Link Up(re-establish)
11. Router Solicitation (with TSLLAO & LMPO)RA delaytimer
10. Addresses to”optimistic” state
15. Identify the link
Mobile HostDNAHostPrefixList
16. Check LMPO
17. Check prefixes in the IPv6 ND prefix list
2. Link-layer addressein ”optimistic” state
7. Link-layer addressin ”preferred” state
DAD timer6. Add prefixes
13. Add prefixes
18. Check prefixes
19. Result
20a. Addresses to”preferred” state
20b. Purge all IPv6 informationand reconfigure it
21b. Select default router
22. Select defaultrouter
23. Signal movement
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Simulation Environment Simulation environment was implemented into NS2
(Network Simulator 2).– IEEE 802.11 Management frames.
Beacon Frame Probe Request and Response Association Request and Response
– Basic IPv6 ND implementation. RS,RA,NS and NA message exchange. IPv6 ND NC for mobile host. Parameter discovery, SAA, NUD, DAD.
– MIPv6 implementation without route optimization.– Three different MD types (Basic, LL Enhanced and DNAv6).– Two DNAv6 solutions for routers (DNAv6 and the FRD).
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Simulation Environment
MH
HA Router
CH
MH
MHMH
1.
2.
3.
4.
Simulation environment includes:– Mobile host (MH), Home Agent (HA), Correspondent Host (CH) and foreign access router.– Home and foreign WLAN access networks.
Four handover scenarios were simulated.
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Results Simulation results from 4 handover scenarios.
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Results Simulation results from 4 handover scenarios when FRD is used.
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Results Simulation results from 4 handover scenarios.
Simulation results from 4 handover scenarios when FRD is used.
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Conclusions
The DNAv6 solutions performes best in every handover scenario.
The DNAv6 offers good base for standardized MD mechanism (access routers and mobile hosts).
The FRD is a good solution for WLAN networks.– Does not require implementation changes to the mobile
hosts.– Only for WLAN. Should be generalized for other wireless
network technologies as well. Further work:
– DNAv4 and DNAv6 interoperability.– Work on the simulation environment.
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