Hi Sunil,

There is not particular bandwidth allocated to any single customer. There a load balancers which are deployed to take care of the performance and traffic for every instance.

For security purpose, since it is a public cloud so, it is somewhat less secure but you can use the webservices to get the data from your own database rather than storing your key data on cloud.

Moreover, Servicenow uses HTTPS protocol to make it furthur secure.

Thanks and Regards,

Vikas Malhotra