Section: 4.5.2 Online mapping
Content: The CTF is a mandatory integrated component of all network elements that are involved in online charging as depicted in figure 4.2.1, with the exception of the S-CSCF (see clause 4.3.2.2.2). If CDR generation by the OCS is required, as described in clause 4.3.2.3, then a CDF is integrated in each OCF that is required to produce the CDRs. All other possibilities for physical mapping, including e.g.: - integrated versus distributed CGF in the OCS, - use of another CGF by the OCS, - IMS GWF integrated in S-CSCF or OCS, or a stand-alone entity, are not specified within the 3GPP standards and are therefore implementation specific. The same is true for the composition of the OCS and its logical functions.