Figure 15.11 Network selection scenario: two credentials and three linksBesides the complexity caused by L2 and L5 signaling, authentication, and
payments, there is also additional complexity attributable to several standards
bodies (such as the IETF, IEEE, and others), as well as commercial consortia
(such as 3GPP and 3GPP2), are all involved in mobility services because of the
huge market potential. The penalty to users will be the very long time until
mobile services across networks will be invisible when changing networks.
The authors believe for these reasons that users will prefer locations where
they enjoy perceived “free” network access, such as is already the case in some
hotels, airline lounges, public places, or in some municipalities.Summary
This chapter has discussed various aspects of mobility, at all levels of the pro-
tocol stack. We have shown some of the key advantages of application layer
mobility using SIP.References
[1] See the web site for OMA at http://www.openmobilealliance.org.
[2] “W* Effect Considered Harmful” by R. Khare. IEEE Internet Computing,
Vol. 3, No. 4, July–August 1999, pp. 89–92.
[3] The 3GPP web site is http://www.3gpp.org.User
“[email protected]” also
known as
“[email protected]”Different credentials
are required for eachAccess Network
1? Access Network 2Access Network
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