SIP is the protocol used over these interfaces.
The DIAMETER protocol is used over interfaces Sh, ISC, Dh, Cx, and Dx. Diameter
can also be found in the charging architecture as described in Chapter 6. Remember
that DIAMETER does not carry session control. It is used for sharing subscriber and
charging data in the IMS domain.
The reference points defined in this chapter provide an outline of all of the major
reference points within the IMS domain. There are others defined by 3GPP2, which
is focusing on the CDMA implementation of the IMS. The model is very similar to the
model and reference points described in this chapter, with additional functions specific
to CDMA networks.
As one can see throughout this chapter, the IMS represents a new architecture for all
networks, but not a network so different than what was implemented to support the IN
and SS7. There are many very similar concepts.
Also remember that this architecture was developed as an evolution of the GSM
network architecture. One of the drivers of redefining networks was to ensure that
security and reliability were preserved when implementing IP in the wireless domain.
Conventional VoIP implementations were inadequate in providing security and did not
interoperate well between various vendor nodes.
This led to many different problems with VoIP implementations within wireless networks
that were already complex.
Pages:
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82