Most people I have spoken to are are absolutely convinced that the Extract process has to be running on the source database host. This thinking comes from all Oracle diagrams where the Extract process is located on the source database host. Till OGG version 11.1.1 this was indeed true. Some have heard that the Extract process can be removed from the source host but it can only done with the Integrated Extract process.
There is however the TRANLOGOPTIONS DBLOGREADER parameter which allows the Classic Extract can be run remotely without any need of accessing the redo/archive logs file system (or ASM).