Handover mechanisms in next generation heterogeneous wireless ...
Handover mechanisms in next generation heterogeneous wireless ...
Handover mechanisms in next generation heterogeneous wireless ...
Create successful ePaper yourself
Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.
DYNAMIC NEIGHBOUR TRUST INFORMATION RETRIEVAL FOR GLOBAL ROAMING<br />
C mf : the cost of AAA signall<strong>in</strong>g <strong>in</strong>curred between the Mobile Host (MH) and the<br />
Foreign AAA (FAAA);<br />
C nb : the cost of AAA signall<strong>in</strong>g <strong>in</strong>curred between the nPOA FAAA and its<br />
associated AAA broker entry;<br />
C bh : the cost of AAA signall<strong>in</strong>g <strong>in</strong>curred between the Home AAA (HAAA) and its<br />
associated AAA broker entry;<br />
C ob : the cost of AAA signall<strong>in</strong>g <strong>in</strong>curred between the oPOA FAAA and its<br />
associated AAA broker entry;<br />
� : the average cost of signall<strong>in</strong>g <strong>in</strong>curred on each AAA hop across the AAA<br />
broker network;<br />
a m : the cost of the AAA related process<strong>in</strong>g at the MH’s term<strong>in</strong>al;<br />
a h : the cost of the AAA related process<strong>in</strong>g at the HAAA;<br />
Accord<strong>in</strong>g to the re-authentication procedure of Figure 4.2, the handover part signall<strong>in</strong>g<br />
cost C H of the NTC retrieval can be represented as:<br />
<strong>in</strong> which<br />
C H � 5 � C mf � 4 � C nb � 4 � Cbh<br />
� a m � 2 � ah<br />
� 4�<br />
� h (Equation 4.2)<br />
nb<br />
hnb �i� represents the trust association hops that the AAA message orig<strong>in</strong>ated<br />
from the nPOA traverses on the AAA broker network <strong>in</strong> handover. It is assumes that the<br />
signall<strong>in</strong>g overheads for the AAA message’s transmission between the nPOA FAAA<br />
and its associated broker, and its transmission between the HAAA and its associated<br />
broker, are the same as what is required for transmitt<strong>in</strong>g AAA message between two<br />
AAA brokers. Thus, when C C � � , the handover part signall<strong>in</strong>g cost C H can be<br />
simplified as:<br />
H<br />
mf<br />
fb<br />
� bh<br />
�2�hnb �i���amah C � 5 � C � 4�<br />
�<br />
� 2<br />
(Equation 4.3)<br />
- 65 -<br />
�i�