Connected vs Connected Headers vs OST file.

[BretAB]

Note: The original 3/23/18 thread (with no replies) for this thread was posted at Connected vs Connected Headers vs OST file. . Today I made this new thread here in the Exchange forum thinking the (old) subject matter may be familiar to Exchange admins. Here's the re-post:

Hi Exchange Forum,

This is an academic question and a bit of a blast from the past, but I'll ask it anyway if it's ok. Also - If this thread should be in the Exchange forum, please advise and I'll move it there.

Test Environment: I tested this on a non-production SBS 2003 VM with a non-production XP client VM, but can't get a definitive result. XP was running an Outlook 2003 client.

Scenario: Outlook is running in Cached Exchange Mode. Outlook presents several receive options via a dropdown control on the lower left hand corner of Outlook. Two of those options are "Connected" and "Connected (Headers)". If I understand correctly, when set to Connected, Outlook will download both headers and content at the same time. Additionally, and if I understand correctly, when set to "Connected (Headers), Outlook will initially download just headers, and then download the content as bandwidth allows.

Here's my test:
1) I exited Outlook on the XP client.
2) On the server, I created an email with a 1MB pdf attachment via the Outlook Web Access interface.
3) I opened Outlook on XP and attempted to notice if there was any difference in the time it took to receive the email and completely open the 1MB pdf attachment using the Headers option, and then the Connected Headers option. There didn't seem to be any noticeable difference in the time. I realize there was only one email and a relatively small attachment by today's standards.

My guess here is that since Cached Exchange Mode is enabled on the XP client, Outlook is always going to download both the header and content, and ignores the "Connected" and "Connected (Header)" options. my thinking being that the purpose of Cached Exchange Mode is to have the header and content in event of the Exchange Server going offline, or likewise having the XP client being a laptop where it would useless to have just the header and no content at 35,000 feet.

Anyone remember if Cached Exchange Mode made the "Connected" and "Connected (Header)" options irrelevant?

Like I said, this is just academic, there's nothing broke to fix here.

Thanks for considering this elongated post. I appreciate any thoughts and comments you care to share.

Regards . . .

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[Diane Poremsky]

Scenario: Outlook is running in Cached Exchange Mode. Outlook presents several receive options via a dropdown control on the lower left hand corner of Outlook. Two of those options are "Connected" and "Connected (Headers)". If I understand correctly, when set to Connected, Outlook will download both headers and content at the same time. Additionally, and if I understand correctly, when set to "Connected (Headers), Outlook will initially download just headers, and then download the content as bandwidth allows.

I believe that is correct. It's been so long that i used outlook 2003 though...
There is also an option, at least in older versions, to only get the headers when working offline - users would need to mark the message to download and outlook would download it on the next mail check. I don't recall if 2003 used connected headers for that or just for the slow sync option.

My guess here is that since Cached Exchange Mode is enabled on the XP client, Outlook is always going to download both the header and content, and ignores the "Connected" and "Connected (Header)" options. my thinking being that the purpose of Cached Exchange Mode is to have the header and content in event of the Exchange Server going offline, or likewise having the XP client being a laptop where it would useless to have just the header and no content at 35,000 feet.

More or less, correct. The header option is/was used when working offline (which is technically different than cached mode, even tho both use an ost) or with slow/expensive connections so users could avoid downloading a lot of messages - headers was fast and the user could then tell outlook which messages to fully download.

Anyone remember if Cached Exchange Mode made the "Connected" and "Connected (Header)" options irrelevant?

Yes, it did. Newer versions of outlook use a different sync method and that option was removed from a later version - i don't recall if 2003 was the last with that option or 2007. The "classic offline" mode is gone as is the control it gave for downloading message.

The same applies to IMAP accounts - you used to be able to get headers only and never get bodies unless you marked them.

 

[BretAB]

I believe that is correct. It's been so long that i used outlook 2003 though...
There is also an option, at least in older versions, to only get the headers when working offline - users would need to mark the message to download and outlook would download it on the next mail check. I don't recall if 2003 used connected headers for that or just for the slow sync option.


More or less, correct. The header option is/was used when working offline (which is technically different than cached mode, even tho both use an ost) or with slow/expensive connections so users could avoid downloading a lot of messages - headers was fast and the user could then tell outlook which messages to fully download.


Yes, it did. Newer versions of outlook use a different sync method and that option was removed from a later version - i don't recall if 2003 was the last with that option or 2007. The "classic offline" mode is gone as is the control it gave for downloading message.

The same applies to IMAP accounts - you used to be able to get headers only and never get bodies unless you marked them.

Hi Diane,

So sorry for the late reply (1040 tax time for the family). I greatly appreciate you taking significant time to revisit this blast from the past. I think this topic is now as well documented as it's ever going to be.

Thank you for sharing your wealth of knowledge here for an academic query. I hope others will find this thread interesting from both a historical and functional perspective.

Regards,
Bret