By default, for a call between users in different Office Communications Server pools, a Call Detail Record (CDR) is written in only one of the pools. If you would prefer for each pool to collect the complete CDR record for every conversation that one of its users is involved in (that is, create duplicate records for cross-pool calls), you can configure the following WMI setting. For details about changing WMI settings, see your Windows Server documentation.
Use WMI to configure the following property of the MSFT_SIPLogOptionsclass on each Front End Server in the pool: CDRBEToken. Set this token to a different value from the default (and a different value from in any other Office Communications Server pool) to cause the cross-pool calls to be archived separately in each pool. The default value is backend_token.