Call Detail Records (CDRs)

• Each call within the PLMN creates a call record
• This record is generated by the MSC/GMSC originating
the call
• The record in known as a ‘Call Detail Record’ (CDR)
• CDRs contain the following information:
• Subscriber Identity
• Number called
• Call Length
• Route of call

Note that the MSC which originates the call keeps control of it throughout subsequent
handovers in order to maintain the CDRs.

Call Charge Outline Procedure

• Network supplies originating MS with CAI details
• MS calculates AOC record using CAI details
• This record acts as a ‘toll ticket’ which tracks the call on its route through
various networks
• Each call component can generate a separate CDR
• The record passes along the backbone to the home network
• Billing computer generates bills based on cumulative CDRs
• HPLMN collects the charges
• HPLM reimburses VPLMN using TAPs in accordance with roaming
agreement