220.127.116.11.7 Default IN Channel
During channel recycling, an inbound proxy MAY have two IN channels active. A default IN channel is a protocol variable that indicates which of the two channels is the default channel. Outside channel recycling, there is only one IN channel at a given point in time, and this channel is always considered the default channel. The default channel MUST be used for sending all RPC PDUs and all RTS PDUs not specifically defined to have different processing rules in section 18.104.22.168.