1. IEEE 802.21 MEDIA INDEPENDENT HANDOVER DCN: 21-07-0xxx-00-0000
Title: Performance analysis of authentication signaling schemes for media independent handovers.
Date Submitted: November 1, 2007
Presented at IEEE session #23 in Atlanta
Authors or Source(s): Antonio Izquierdo, Katrin Hoeper, Nada Golmie, Lily Chen
Abstract: In this contribution different authentication signaling schemes including full authentication, re-authentication, and indirect pre-authentication are evaluated for media independent handovers. Simulation results are obtained with IEEE and IEEE handovers.
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2. IEEE 802.21 presentation release statements
This document has been prepared to assist the IEEE Working Group. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein.
This is a contribution by the National Institute of Standards and Technology and is not subject to copyright in the US. The contributors do not have the authority to override the NIST policy in favor of the IEEE policy.
The contributor is familiar with IEEE patent policy, as stated in Section 6 of the IEEE-SA Standards Board bylaws < and in Understanding Patent Issues During IEEE Standards Development
IEEE presentation release statements
This document has been prepared to assist the IEEE Working Group. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein.
The contributor grants a free, irrevocable license to the IEEE to incorporate material contained in this contribution, and any modifications thereof, in the creation of an IEEE Standards publication; to copyright in the IEEE’s name any IEEE Standards publication even though it may include portions of this contribution; and at the IEEE’s sole discretion to permit others to reproduce in whole or in part the resulting IEEE Standards publication. The contributor also acknowledges and accepts that this contribution may be made public by IEEE
The contributor is familiar with IEEE patent policy, as outlined in Section 6.3 of the IEEE-SA Standards Board Operations Manual < and in Understanding Patent Issues During IEEE Standards Development
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3. Outline Goals and motivation
Review of authentication signaling schemes
Simulation environment
Performance metrics
Simulation parameters
Performance results
Security signaling latency
Cryptographic processing time
Impact of network topology on indirect pre-authentication
Transmission delay
Handover latency
Summary
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4. Goals and motivation
The main goals of this contribution are to analyze the performance of different authentication signaling mechanisms in the context of heterogeneous handovers
Simulation models are developed to evaluate the performance of the following three authentication signaling schemes:
Full Authentication
Indirect pre-authentication
Re-authentication
Heterogeneous handovers are considered in the context of IEEE and IEEE networks.
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5. Full Authentication
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6. Indirect pre-authentication
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7. Re-authentication
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8. Simulation environment
Used NS-2 with IEEE and module extensions (available from
Developed extensions to model authentication in and networks using EAP:
Implemented EAP framework as defined in RFC 3748 including TTLS-MD5 and GPSK methods
Developed an authentication module to support full authentication, re-authentication and Handover Process Optimization as defined in IEEE e
Developed an authentication module to support full authentication in RSN and re-authentication in the mobility domain
Developed support for pre-authentication using the extensions
Developed a limited RADIUS implementation for Key and EAP message transfers
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9. Authentication
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10. Authentication
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11. Authentication
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12. Performance metrics (1)
EAP latency denotes the time elapsed between the sending of the EAP Start message until the receipt of either the EAP SUCCESS / EAP FAILURE message. It is included in the Full authentication signaling latency, but not in the pre-authentication signaling latency.
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13. Performance metrics (2)
Security signaling latency is defined as the time elapsed between the sending of the first authentication message until the reception of the ACK for the last message:
802.11
802.16
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14. Performance metrics (3)
Transmission delay is the time it takes a packet to reach its destination.
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15. Performance metrics (4)
Handover delay represents the time elapsed between when a decision to handover is executed until the traffic is redirected to the new interface.
The decision to perform a handover is made when a new link is detected and if the new link is better than the current link or if the current link is disconnected.
The cryptographic processing delay is the time spent by the mobile node to perform different cryptographic operations including encryption, decryption, hash, validation, and key derivation.
Note that the results obtained represent mean values averaged over 100 simulations.
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16. Network Topology 1
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17. Simulation Parameters (1)
The traffic flows from a corresponding node in the backbone network to the mobile node
networks configuration
Data rate: 11 Mb/s
Coverage area radius: 50 m
802.16
Coverage area radius: 500 m
Key lifetimes are longer than the simulation time, so the mobile node does not need to refresh them or re-authenticate with the current PoA
The mobile node does not use MIH triggers
The interface is preferred over the interface.
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18. Simulation Parameters (2)
The authentication lifetime is larger than the simulation time
The size of the DH authentication keys is 1024 bits
The size of the symmetric authentication keys is 128 bits
The size of the IDs is 64 bytes
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19. Simulation Results: Security Signaling Latency using EAP GPSK
In this case full authentication was performed
Note that the cryptographic processing (computed as an example on a Palm tungsten) is ms which is equivalent to 9.08 % of the EAP time in or 7.72 % of the EAP time in
Authentication time %
802.11
802.16
Open Authentication
1.98 ms
0.99 %
EAP Authentication ms
96.16 %
Association
1.62 ms
0.81 %
TEK Request
9.05 ms
5.84 % ms
96.28 %
4-Way Handshake
3.84 ms
1.92 %
Authentication time %
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20. Simulation Results: Security Signaling Latency using EAP TTLS-MD5
In this case full authentication was performed
Note that the cryptographic processing (computed as an example on a Palm tungsten) is ms which represents % of the EAP time in or % of the EAP process in
Note that DH Agreement takes ms measured on the same platform.
802.11
802.16
Open Authentication
1.98 ms
< 0.01 %
EAP Authentication ms
99.97 %
Association
1.62 ms
TEK Request
9.05 ms
0.03 % ms
99.98 %
4-Way Handshake
3.84 ms
0.01 %
Authentication
time %
Authentication
time %
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21. Simulation Results: Comparing different authentication signaling schemes (GPSK)
Full
Auth
Re-Auth
Improv. over Full Auth.
Indirect
Pre-Auth
Sign.
Laten.
235.42
[0.013]
70.42
[0.001]
70.09%
10.42
[0.171]
95.57%
EAP
laten.
226.37
61.37
72.89%
422.42
[0.136]
-86.61%
GPSK
Full Auth
Re-Auth
Improv. over Full Auth.
Indirect
Pre-Auth
Sign.
laten.
194.33
[0.672]
46.59
[0.510]
76.03%
3.01
[0.371]
98.45%
EAP
192.47
[0.608]
45.07
[0.417]
76.59%
422.42
[0.136] %
All times are expressed in milliseconds unless stated otherwise
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22. Simulation Results: Comparing different authentication signaling schemes – (TTLS-MD5)
Full Auth
Re-Auth
Improv. over Full Auth.
Indirect
Pre-Auth
Sign.
laten.
[0.001]
70.42
[0.014]
99.78 %
10.42
[0.171]
99.96 %
EAP
61.37
99.80 %
[0.366] %
– TTLS – MD5
Full Auth
Re-Auth
Improv. over Full Auth.
Indirect
Pre-Auth
Sign.
laten.
[0.751]
46.59
[0.450]
99.85 %
3.01
[0.371]
99.99 %
EAP
[0.705]
45.07
[0.395]
[0.366] %
All times are expressed in milliseconds unless stated otherwise
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23. Simulation Results: Transmission Delay (Network Topology 1)
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24. Simulation Results: Transmission Delay (Network Topology 1)
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25. Few observations on the security signaling latency
Both re-authentication and indirect pre-authentication schemes reduce the security signaling latency by more than 70%
EAP latency in indirect pre-authentication increases as a result of the longer path used by the EAP messages
This would force the mobile device to make the handover decision sooner than when performing a normal network entry
With re-authentication the EAP latency is reduced
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26. Simulation Results: Impact of cryptographic processing delay (GPSK)
802.16
Full Auth
Re-Auth
EAP latency
226.37
61.37
Cryptographic delay
17.48
1.02
7.72 %
1.66%
802.11
Full Auth
Re-Auth
EAP latency
192.47
45.07
Cryptographic delay
17.48
1.02
9.08%
2.26%
Note that an indirect pre-authentication requires the same cryptographic operations as a full authentication.
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27. Simulation Results: Impact of cryptographic processing time (TTLS-MD5)
802.16
Full Auth
Re-Auth
EAP latency
61.37
Cryptographic delay
1.02
98.24 %
1.66 %
802.11
Full Auth
Re-Auth
EAP latency
45.07
Cryptographic delay
1.02
98.51%
2.26 %
Note that an indirect pre-authentication requires the same cryptographic operations as a full authentication.
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28. Observations on the cryptographic processing delay
Pre-authentication does not reduce the amount of cryptographic processing delay of a full authentication
The cryptographic processing delay may in fact increase due to secure tunnel negotiations
Re-authentication reduces the time spent in cryptographic processing since the number of messages exchanged is reduced
Re-authentication may be alternative to a full authentication when the time to do a full authentication is a cause of concern (other concern considerations include battery life and power consumption)
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29. Simulation Results: Handover delay
802.16
Full Authentication
Re-Authentication
Indirect
Pre-Authentication
GPSK
990.84
930.84
TTLS-MD5
802.11
Full Authentication
Re-Authentication
Indirect
Pre-Authentication
GPSK
921.93
717.84
677.87
TTLS-MD5
Values are in milliseconds
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30. Observations on the handover delay
Re-authentication reduces the total handover delay, independently of the EAP used
Indirect pre-authentication reduces the handover delay as long as it is possible to fully run the authentication method before the network entry takes place
If the pre-authentication is not completed at the time of the network entry, a new full authentication starts. In this case the situation is the same as in a full authentication
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31. Network Topology 2
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32. Indirect Pre-Authentication Indirect Pre-Authentication
Simulation Results: Indirect Pre-Authentication (Network Topology 2)
GPSK
GPSK
Full Auth
Indirect Pre-Authentication
Improv. over Full Auth.
Security Signaling
Latency
275.42
[0.013]
10.42
[0.171]
95.57%
EAP Latency
266.37
[0.001]
621.32
[0.156] %
Full Auth
Indirect Pre-Authentication
Improv. over Full Auth.
Security Signaling
Latency
234.33
[0.672]
3.01
[0.371]
98.45%
EAP Latency
232.47
[0.608]
621.32
[0.156] %
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33. Indirect Pre-Authentication Indirect Pre-Authentication
Simulation Results: Indirect Pre-Authentication (Network Topology 2)
– TTLS-MD5
– TTLS-MD5
Full Auth
Indirect Pre-Authentication
Improv. over Full Auth.
Security Signaling
Latency
[0.127]
10.42
[0.171]
99.97 %
EAP Latency
[0.126]
[0.277] %
Full Auth
Indirect Pre-Authentication
Improv. over Full Auth.
Security Signaling
Latency
[0.241]
3.01
[0.371]
99.99 %
EAP Latency
[0.237]
[0.305]
-2.16 %
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34. Observations on indirect pre-authentication for network topology 2
EAP latency in indirect pre-authentication depends heavily on the network topology considered
The impact is greater for fast authentication methods.
Topology information must be available beforehand in order to perform the pre-authentication on time
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35. Summary
Re-authentication and indirect pre-authentication reduce the time required for authentication during a handover
Indirect pre-authentication allows for a shorter security signaling latency during the network entry, at the expense of requiring more time in advance for handover preparation
Re-authentication reduces the cryptographic processing time and its performance does not depend so much on the network topology considered
Either the indirect pre-authentication or re-authentication technique can be used. Deciding which technique to use depends on the scenario considered
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36. Backup
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37. Cryptographic processing delay assumptions
Examples for cryptographic processing time used are real values in milliseconds obtained from a Palm Tungsten T3:
* Value under the precision of the device timer
These values are dependent on the platform used and therefore should not be used as absolute values. The intention here is to compare between the different cryptographic methods available on a given platform.
Size of the encrypted data
16 bytes
128 bytes
512 bytes
AES 128 (encrypt)
3.04
7.39
32.61
AES 128 (decrypt)
3.11
7.67
33.18
MD5 0*
2.17
SHA1
1.3
Key size
512 bits
768 bits
1024 bits
DH Agreement
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38. EAP: Generalized Pre-Shared Key
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39. EAP: TTLS-MD5
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