I am new to routing switching. Can some one guide me how to configure SSH on routers?
First you need a crypto image. Check to see that you have a k9 feature set (e.g. ipservicesk9). Then, make sure you have a hostname and domain name configured:
ip domain-name company.com
Then you need to generate you RSA certificate:
crypto key generate rsa
When it prompts you for a modulus, choose one that is at least 1024 for best compatibility.
Next, configure a local username. If you are already using AAA you can skip this step:
aaa authentication login default local
username sshuser password sshuser!@#
Finally, checkout the optional "ip ssh" commands to see if any of them are needed for your setup. However, at this point, you should be able to ssh to your router as sshuser (or whatever AAA users you have available).
See http://www.cisco.com/en/US/products/sw/iosswrel/ps1835/products_configuration_guide_chapter09186a00800ca7d5.html#wp1007881 for the complete list of instructions.