116 Software Networks
We shall begin by discussing macromobility, which involves the
management of mobility of terminals between two different IP
domains, and micromobility, which relates to the change of
attachment point within the same IP domain. In the first case, the main
protocol is IP Mobile; in the second, various protocols are in
competition with one another. We shall then go on to examine
multihoming – i.e. the case where a terminal is simultaneously
connected to several networks.
5.5. Mobility control
Two main types of mobility control solutions in IP networks have
been put in place, depending on the mobile terminal’s movement:
support for macromobility and support for micromobility.
In the former case, the mobile changes the IP network, whereas in
the latter, it stays within the same network but changes its attachment
antenna. Macromobility is handled by the IP Mobile protocol. For
micromobility, numerous protocols have been defined. We shall
examine the main ones in this chapter.
5.5.1. IP Mobile
IP is increasingly being presented as a solution to the problems
posed by mobile users. The IP Mobile protocol can be used in IPv4,
but the potential lack of addresses complicates the management of
communication with the mobile. IPv6 is preferable, because of the
large number of available addresses, which means that temporary
addresses can be assigned to the stations as they move around.
The operation of IP Mobile is as follows:
– a station has a base address, with an agent attached to it, whose
role is to monitor the match between the base address and the
temporary address;
– when a call comes into the mobile station, the request is sent to
the database in which the base address is held;
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We shall begin by discussing macromobility, which involves the
management of mobility of terminals between two different IP
domains, and micromobility, which relates to the change of
attachment point within the same IP domain. In the first case, the main
protocol is IP Mobile; in the second, various protocols are in
competition with one another. We shall then go on to examine
multihoming – i.e. the case where a terminal is simultaneously
connected to several networks.
5.5. Mobility control
Two main types of mobility control solutions in IP networks have
been put in place, depending on the mobile terminal’s movement:
support for macromobility and support for micromobility.
In the former case, the mobile changes the IP network, whereas in
the latter, it stays within the same network but changes its attachment
antenna. Macromobility is handled by the IP Mobile protocol. For
micromobility, numerous protocols have been defined. We shall
examine the main ones in this chapter.
5.5.1. IP Mobile
IP is increasingly being presented as a solution to the problems
posed by mobile users. The IP Mobile protocol can be used in IPv4,
but the potential lack of addresses complicates the management of
communication with the mobile. IPv6 is preferable, because of the
large number of available addresses, which means that temporary
addresses can be assigned to the stations as they move around.
The operation of IP Mobile is as follows:
– a station has a base address, with an agent attached to it, whose
role is to monitor the match between the base address and the
temporary address;
– when a call comes into the mobile station, the request is sent to
the database in which the base address is held;
www.it-ebooks.info