B.E 2007 Graduate(age 28) . working in BPO -technical support executive . but like to change career to networking or linux server

iam B.E 2007 Graduate(age 28) . working in BPO -technical support executive (4 years Exeprience ). but like to change career to networking or linux server.Please suggest me best reputed institutes with fee structure in south chennai . especially in tambaram , chromepet or sanatorium