In SR 8.0.4, you will only find Packets In & Packets Out for Ethernet port (if you need to get this data you have to go to older versions: 7.0.x as they are no more supported in 8.0.x and later). You can download the software "MG-SOFT MIB Browser Professional Edition with MIB Compiler" from http://www.mg-soft.si/download.html and compile Ascend MIBs and let the software browse the box with SNMP. You will get a tree of what oids are available and their name, then you can choose what you want and get the right oid corresponding to them. I don't know what is the right SNMP to disconnect a user from a modem but you can try with RFC1696.