The IBM Multiprotocol Switched Services (MSS) module here fits in the 8265 ATM chassis and provides LAN emulation services as well as IP routing between ELANS. 8210hs.pdf
It is a stand alone module configured independantly from the host switch and connects via an internal 155MB/s port to the switch backplane.
Initial config is via a 9 pin D serial port at 19200 baud.