Today we received an email from Mike on the CrackBerry Podcast hotline (podcast @ crackberry.com) in New Jersey asking why there are different web browsers on his new BlackBerry Storm, and why he cannot download files larger than 5 Mb.

I thought that the answer to Mike's question would also benefit everyone else, so read on after the jump for an explanation of the BlackBerry Browser.

How Many Browsers?

Today a BlackBerry can have a number of web browsers. They all serve a purpose but can be confusing. Let's start with the different ways that your BlackBerry can be setup.

Corporate
In a corporate environment, your BlackBerry is assigned to a BlackBerry Enterprise Server (BES). The BES allows the administrators to fully control your BlackBerry, including how you browse the internet. Every BES has a service called the Mobile Data System Connection Service (MDS-CS). This service allows data to flow between your BlackBerry and the BES, and eventually onto your company's network.

Carrier
If you are a non-corporate BlackBerry user then your BlackBerry is assigned to a BlackBerry Internet Server (BIS) that is installed either on your carriers network or Research In Motion's (RIM) network. The BIS is a slightly different version of the BES that allows only email and web browsing.

Your Home (Unite)
If you want to have your own BES at home, or if you run a small business, you can download the free Unite software from RIM. Unite is essentially a stripped down BES that runs on a PC in your house. It supports up to five BlackBerrys.

So you are probably thinking that if your BlackBerry can be assigned to a BES, a BIS, or Unite that you would have three browsers. You would be correct, but your carrier can add another one, and if your BlackBerry has Wi-Fi, you will have another.

In total, five possible browsers. Here they are:

1. BlackBerry Browser

1. This browser is only used in a corporate environment. All web browsing goes via the BES using the MDS-CS service. The MDS-CS service acts as a proxy for the BlackBerry Browser and also strips out web page content that is not suitable for the BlackBerry.
2. MDS-CS also compresses the data before it is sent to minimize wireless data usage and resizes images based on the device they are going to (yes it keeps track of the screen resolution of each device registered with it and resizes images accordingly).
3. Because the BlackBerry Browser gets all of its content via the BES's MDS-CS service, the BlackBerry user can browse internal company web sites. If the network administrator wants to block certain web sites on a desktop and BlackBerry, they simply configure the BES to use the company's internet proxy serves and/or firewall.
4. The browsing speed is affected by how busy the BES is. The BES prioritizes email over web browsing and other tasks, so if your company's BES is too busy, your web browsing will suffer.
5. Data path: BlackBerry <-> Carrier <-> RIM NOC <-> BES <-> Internet

2. Internet Browser

1. This browser is on every BlackBerry unless your BlackBerry is on a BES, and the administrator has explicitly disabled it. All web browsing from this browser goes via the BIS using the MDS-CS service.
2. Since web browsing is going via MDS-CS, all of the same features that are listed above apply.
3. It is certainly conceivable that a busy BIS can affect web browsing.
4. Data path: BlackBerry <-> Carrier <-> RIM NOC <-> BIS <-> Internet

3. WAP Browser

1. WAP stands for Wireless Access Protocol and is an old wireless standard for web browsing (when mobile browsers were very, very limited). The carrier has a WAP Gateway that this browser connects to. The WAP Gateway is setup to get a very limited subset of web sites.
2. The WAP gateway translates regular web pages to a language that the WAP browser can understand.
3. Data path: BlackBerry <-> Carrier <-> WAP Gateway <-> Internet

4. Unite Browser

1. This browser is available if your BlackBerry is assigned to your Unite server. Since Unite is a stripped down BES, it too has an MDS-CS service and so all of the same MDS-CS features are available as listed above
2. Your PC running Unite must be running at all times otherwise this browser cannot function.
3. Data path: BlackBerry <-> Carrier <-> RIM NOC <-> Unite <-> Internet

5. Wi-Fi Browser (sometimes called the HotSpot Browser)

1. This browser is available if your BlackBerry has Wi-Fi (BlackBerry Bold, Curve 8320, etc.).
2. This browser does not use any servers but goes directly to the internet.
3. This is by far the fastest browsing experience since it is just you and the internet
4. Data path: BlackBerry <-> Wi-Fi HotSpot <-> Internet

Please note that if your BlackBerry is assigned to a BES, your administrator can remove all browsers, or leave you with just the BlackBerry Browser. This is normally done for compliance and/or security reasons.

Bonus Round from Kevin: Since this email came into the podcast hotline and in true CrackBerry Podcast fashion we tend to both chime in on responses (Craig is the Expert and I'm the Addict in case that isn't clear! LOL) I'm going to toss in a sentence here. It'll be back to Craig after the italics are done.

Just to make things more confusing, sometimes carriers toss in an extra browser for good measure... note the Rogers Mall browser below on my BlackBerry Bold:

One web browser with soo many "flavors"

Browser Content Size Restrictions

As Mike pointed out, there is a limit to the file size that can be downloaded. This is true for the BES, BIS, and probably Unite since all use the MDS-CS service. By default MDS-CS limits the size of the content that it will send a BlackBerry. On a BES, the administrator can override this limit by editing the MIME types in the MDS-CS configuration and making the Maximum KB/Connection setting higher. I am not sure if this can be done on BIS.

The Wi-Fi Browser does not have a limit since it connects to the internet directly. I am not sure about WAP, but I can only guess that its limit is very low.

I hope that helps clear things up a bit.

[ Craig Johnston is the author of Professional BlackBerry and is CrackBerry.com's Podcast co-host and resident enterprise guru and all-round BlackBerry expert. If you have an enterprise application or topic that you would like to have addressed by Craig, send him an email at crackberrycraig @ crackberry.com. ]