Forgive me but you are not very descriptive as
"disconnection" means different things to different people
- If you are getting a true disconnect and being booted to login screen that is more often than not a local issue.
- If you are getting booted to character select then that is more likely an ESO issue.
- Complete client crashes are a different story all together but again, most likely local.
In all that, server overcrowding has been causing some issues, more than normal.
In the end it is best to open up a tech support ticket as they can help you figure out what is happening.