Blackberry mail service basics?

Can someone explain very briefly the way Blackberry's email functions. I'm not looking for nuts and bolts, just answers to some very basic questions:

• Does a Blackberry check with an Exchange server directly, or does it always/ever use an intermediate server?
• If it uses an intermediate server, is that server managed by RIM, or the customer's mobile network operator?
• To configure Exchange email on a Blackberry, do you enter the settings on the phone itself, or via a web interface?
• What other email protocols can Blackberry devices use, and do they (also?) use an intermediate server?

Solution 1:

You have a few non-exclusive options for email on Blackberries:

• BIS: This is the Blackberry Internet Service mail provider. It's what you are configuring when you go to http://bis.$REGION.blackberry.com/html?brand=$PROVIDER. The BIS servers (managed by RIM) act as an intermediary between the actual mail server and Blackberry devices. BIS is able to:
  • pick up mail from POP3 or IMAP mailstores and delivers them to your Blackberry device.
  • you can configure a username@$PROVIDER.blackberry.net email address that requires no external mail server to work
  • BIS only provides one-way mail sync (if you delete a message on your Blackberry, it can also be deleted from the server)
• BES: This is the Blackberry Enterprise Server option. You are using Domino, Exchange or Groupwise and have purchased the BES software from RIM. You run a server at your office that acts as a gateway between your mail server and devices. (Or, you have someone hosting your BES). It also provides:
  • Mailbox synchronization
  • Calendar synchronization
  • Access to the corporate network
  • Lots of other Enterprisey features
• 3rd party: Third parties (such as GMail) can provide applications that run on your Blackberry - you then interact with them through that application, not the native Blackberry functionality.

Notes:

• To use BES over your carrier's network, you must have a 'corporate' (Read: more expensive) plan from your carrier.
• It's possible to use BES over wifi with no carrier activation

Solution 2:

There are two ways of using a Blackberry. You can use BIS (Blackberry Internet Service) which will talk to your email system via POP or IMAP. Your handheld will talk to this service to grab email. This is done on a phone-by-phone basis and cannot be centrally managed.

The other way is by installing BES (Blackberry Enterprise Server). This is an intermediate service running on your network. It attaches to Exchange and monitors the email accounts of whatever users are configured in it. In the BES console, you key the PIN of the device you want to link, and the settings are sent down. From this console, you can adjust folders that are available to each handheld, brick phones, change security settings, etc. You do have to pay licensing on this software in addition to changes to your Blackberry plan. BES integrates almost all the features found in Outlook into the Blackberry; contacts, tasks, calendar, email, notes.

Personally, if you have more than a few Blackberry devices and run your own Exchange server, I would opt for the BES system. It's flexible and much easier to manage.