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ously.
8
4.2. CR based Scheme
before the handoff and the delay caused by DAD can be
avoided.
If the aircraft finds that it will switch to a new CN
(ground station), the MR can perform the CR discovery
before handoff.
The MR has to perform Return Routability Procedure
and update the binding for each CR after handoff, but the
process can be optimized to shorten the delay. The MR
can send out the HoTI message (with MR’s Home
Address as source address) and capture the 2 NPT
messages before handoff, then when the MR switches to
the new Access Router and finish configuring the new
Care-of Address, it can send out the CoT message (to the
CR, with the Care-of Address as the source address) and
the BU message (to the HA for Home Registration)
simultane
The whole handoff process is depicted in Figure 5
Compared with Equation (1), the handoff delay of the
optimized process is:
13
tep stepstep
TT TT (2)
4. Route Optimization for PIES Domain
The route optimization for the PIES domain is much
harder because the CNs in this domain are globally
located, and we cannot raise new requirement to the
infrastructure.
the routing to some extent.
throughput.
d.
Possible methods include multiple HAs scheme and
CR based scheme, but generally speaking, these methods
are effective only in some special scenarios.
4.1. Multiple HAs Scheme
As we have mentioned in Section 2.3, it’s impossible for
multiple HAs to cooperate for a single flow, and once the
MR switches from one HA to another, it has to change
the Home Address. However, in some special cases, we
can let the MR register to multiple HAs simultaneously
and let the passenger choose which HA to use.
For example, an aircraft is flying from China to France,
and it has two HAs―one in China and one in Europe.
The aircraft provides the passengers with two Wi-Fi
hotspots named “for Europe” and “for China”,
respectively. For a passenger who mainly access the
websites in China, he should connect to the “for China”
hotspot so as to get an IP address managed by the HA in
China, and for a passenger who mainly access the
websites in Europe, he should connect to the “for
Europe” hotspot so as to get an IP address managed by
the HA in Europe. In this way, the passenger can
manually select the HA that is closer to the CNs, and
thus optimize
Correspondent Routers can be deployed not only in the
aeronautical networks, but also in common Internet. If a
CR can be found, the route to/from the related CNs can
be optimized. However, the load for CR discovery and
route optimization can be very heavy considering the
unlimited number of CNs.
So there must be some mechanism to limit the
workload. For example, the MR can set an upper limit on
the total amount of MR-CR tunnels, and the MR
discovers CRs only for the sessions with the longest
packet delay or largest
5. Conclusions
In this paper, we treat the route optimization problem for
the ATS and AOS domains and for the PIES domain
separately. For the ATS and AOS domains, we raise
some new requirements to the Correspondent Routers
and Access Routers, so that the optimal routing is
realized while the handoff delay is reduced. Multihoming
is supported by the HA, but the CR’s support to multiple
Care-of Addresses registration will be left for future
research. For the PIES domain, the route optimization is
harder because we cannot raise new requirement to the
infrastructure, so only 2 possible methods for some
special scenario are discusse
6. Acknowledgements
This work was supported by a grant from the Major State
Basic Research Development Program of China (973
Program) (No. 2009CB320400).
7. References
[1] International Civil Aviation Organization, “Manual for the
ATN Using IPS Standards and Protocols (Doc 9896),” 1st
Edition, Unedited Advance Version, February 2009.
[2] W. Eddy, W. Ivancic and T. Davis, “Network Mobility
Route Optimization Requirements for Operational Use in
Aeronautics and Space Exploration Mobile Networks,”
RFC 5522, October 2009.
[3] Christian Bauer and Martina Zitterbart, “A Survey of
Protocols to Support IP Mobility in Aeronautical Com-
munications,” IEEE Communications Surveys & Tutori-
als, Vol. PP, No. 99, 2010, pp. 1-16.
doi:10.1109/SURV.2011.111510.00016
[4] D. Johnson, C. Perkins and J. Arkko, “Mobility Support
in IPv6,” RFC 3775, June 2004.
[5] V. Devarapalli, R. Wakikawa, A. Petrescu and P. Thubert,
“Network Mobility (NEMO) Basic Support Protocol,”
RFC 3963, January 2005.
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