Google:
http://community.arubanetworks.com/t5/ArubaOS-and-Controllers/MAC-Address-Authentication-Server-Group/td-p/8808/page/2
http://www.google.com.hk/#q=aruba+guest+mac+address&hl=zh-CN&newwindow=1&safe=strict&prmd=imvns&ei=rk3DT7vDKKjeigeBwK2wCg&start=10&sa=N&fp=1&biw=916&bih=761&bav=on.2,or.r_gc.r_pw.,cf.osb&cad=b
Aruba
http://support.arubanetworks.com/Default.aspx?tabid=111&loc=https://kb.arubanetworks.com/app/answers/detail/a_id/124/kw/xml%20guest%20user
https://kb.arubanetworks.com/app/answers/detail/a_id/124/kw/xml%20guest%20user
https://kb.arubanetworks.com/app/answers/detail/a_id/1063/kw/xml%20api