Seamless Synchronization

For synchronization to occur, there is nothing you, the user, do to initiate it.  No buttons to push, no progress dialogs to wait for.  It just happens automatically; however, because of the power of synchronization, some user habits can have unintended consequences.  You may not want to synchronize that fifty megabyte attachment to a hundred other users, but that's exactly what you may unintentionally do if you're not careful!  It is important to read the Best Practices section so you know what to do and what not to do in synchronized folders.

There are also a few details to know about how synchronization works which will help it make sense when unexpected changes happen.  Please read the following sections to become familiar with the basic operation of Add2Exchange, what features are available and your options for how synchronization behavior may be configured.

Information Availability

Synchronization makes the information which you depend on available to you or others in ways not possible before.  For example, mobile device users frequently employ synchronization to make a company contact list or group calendar available on the go. Add2Exchange also enables groups to better collaborate, simplify the sharing of appointments, meetings and contacts among multiple users in the office.

The manner in which Add2Exchange accomplishes this is to synchronize items between public and private folders, in any combination and any direction.  Because Add2Exchange provides seamless synchronization, it runs behind-the-scenes on the organization's Exchange server, which provides Add2Exchange centralized access to users' folders and public folders.

By working directly with Microsoft Exchange, Add2Exchange provides information where other solutions can pick it up for further distribution.  This is the case with mobile devices, which perform their own synchronization with Outlook folders.  In this situation, Add2Exchange is an extension of the synchronization capabilities of these devices, providing them access to resources outside of their normal reach. Add2Exchange brings information from other folders to the user's folder, where it is within reach of the mobile device to synchronize through its usual synchronization capability.

Add2Exchange is known to work with most if not all mobile devices which have Outlook, BlackBerry or Microsoft ActiveSync synchronization capability.

Public Folder and Mailbox Synchronization

Add2Exchange synchronizes items between folders within the same organization.  Synchronization may be performed between any combination of public and mailbox folders (also referred to as Private  or Personal folders), provided the folders contain items of the same type (calendar appointments, contacts, tasks).

Because Add2Exchange distinguishes between the source (the folder new items are created in) and destination folders (the folder you want the items to sync/replace to), this means you may build relationships in any of four combinations:

Public folder to Private folder
Private folder to Public folder
Private folder to Private folder
Multiple Public to Multiple Personal folder
Public folder to Public folder

Relationships

Synchronization with Add2Exchange is founded on the concept of a relationship between a source and a destination folder.  A relationship brings the contents of one folder to another, the contents of the source to the destination.

Note: a relationship does not bring the contents of the destination folder to the source folder.  While you may define another corresponding relationship which does so, when you are looking at any particular relationship, that relationship is only responsible for synchronizing the contents of its source to its destination.

There are various kinds of relationships, with configurable options for behavior.  The most important thing to understand, however, is that there is one relationship for each pair of source and destination folders.  This means, for example, if you have a single public source folder which you want to synchronize to several users, you will need to create one relationship from the public folder (the source) to each of the user's folders (the destinations).

Relationships Between Pairs of Folders

There are three general synchronization behaviors for a pair of folders.  These are controlled by the specific settings employed by your administrator.  Consult your administrator for the details of your relationship type.

The three types are:

One-way Synchronization:

Items from the source folder are synchronized to the destination but changes to copies cannot affect originals in the source.

Two-way Synchronization:

Items from the source folder are synchronized to the destination and changes to copies can affect originals in the source.

Mutual Synchronization:

Items from each folder are synchronized to the other folder.  Both folders end up with an equivalent set of items.  Note this is actually two relationships.  Each relationship may be configured separately, but by convention usually have the same settings.  Mutual relationships may be either one-way or two-way.

For details on each of these types of relationship, refer to the section Synchronization_Models.

One-way Synchronization

One-way synchronization copies items from one folder to another and keeps the copies in sync with changes to the originals in the source folder.  In the illustration above, we use a red folder to represent the source folder items and a blue folder to represent the destination folder.

A copy of the contents of the red folder is synchronized to the blue folder.  Note that the copy of the red folder in the illustration represents the contents of the red folder, as opposed to creating the red folder as a subfolder of the blue one.

Changes to the copies of the red folder's contents are not synchronized back to the red folder, as represented by the lock on the red folder copy in the illustration.

Two-way Synchronization

Two-way synchronization copies items from one folder to another and keeps the copies in sync with changes to the originals in the source folder.  As before, we use a red folder to represent the source folder items and a blue folder to represent the destination folder.

A copy of the contents of the red folder is synchronized to the blue folder.  Note that the copy of the red folder in the illustration represents the contents of the red folder, as opposed to creating the red folder as a subfolder of the blue one.

Changes to the copies of the red folder's contents are synchronized back to the red folder, as represented by the opened lock on the red folder copy in the illustration.

Mutual Synchronization

Mutual synchronization employs two relationships, usually two-way relationships, to make both folders contain an equivalent set of items.  This term describes the fact that there are two relationships between the pair of folders rather than whether changes to copies are synchronized back to the source, so it describes a different concept.  Each of the mutual relationships can therefore also be one-way or two-way.

In the illustration, a copy of the contents of the red folder is synchronized to the blue folder and vice-versa.  Note that the blue folder's copy of the red folder items are automatically excluded by Add2Exchange in the return relationship from the blue folder back to the red.  This prevents copies of copies from being made forever and filling up your server.

Changes to the copies of the red folder's contents are synchronized back to the red folder, as represented by the opened lock on the red folder copy in the illustration.

In practice, Add2Exchange synchronization does not always synchronize the entire contents of a folder to the destination.  This is by design because, for example, you are typically not concerned with appointments which occurred in the past.  Because of this, mutual relationships do not always make the folders contain strictly the same set of items.  But usually, you have an equivalent set of the items about which you care.

Relationship Arrangements

Now that you understand the behavior of relationships, there are four synchronization models which describe how relationships are arranged to achieve an overall synchronization goal.  They are:

Folder Publication:

Publishing (synchronizing) folder contents to others without the ability for the users to affect items in the published folder, just like the manuscript of a book cannot be modified by people with a published copy.

Folder Participation:

Synchronizing folder contents to others with the ability for users to participate in making changes to the source folder.  Others do this by changing their local copies of items, which Add2Exchange then synchronizes back to the source.

Folder Aggregation:

Synchronizing the contents of multiple folders to a single folder.  This gives an aggregate view of several other folders in a single folder.

Folder Grouping:

Synchronizing the contents of multiple folders to each and every other folder so they all contain an equivalent set of items.  The folders are a group containing one set of items.  This is also referred to as a "full mesh" sync scenario.

The following table summarizes their attributes:

Model

Relationship Type

Relationship Arrangement

Number of Relationships Required

Folder Publication

One-way

Single source to X destinations

X

Folder Participation

Two-way

Single source to X destinations

X

Folder Aggregation

One-way or Two-way

X sources to single destination

X

Folder Grouping

Mutual

X participants (public folders count), mutual relationships between every distinct pair of folders

X * (X - 1)

Example: 3 users and 1 public = 4 * (4 -1) = 12

These are discussed in more detail in the section Synchronization Models.

Terminology Change

Prior versions of this guide and the administration guide used different terms for the same concepts in some cases.  These terms have been changed to better communicate the nature of the concepts being discussed and clarify the distinctions between them.  The following table summarizes the changes:

Old Term

New Term

Meaning

Unidirectional

One-way

See "one-way" above.

Bidirectional

Two-way

See "two-way" above.

One-way

No new term.  This is implied by the term "relationship" itself.

The inclusion of items from one folder in another via a relationship.

Two-way

Mutual Relationship

Two relationships between a pair of folders so their contents are equivalent.

Reciprocal (or Inverse) Relationship

Mutual Relationship

Refers to the second relationship of such a pair.

Full Mesh Relationship

Folder Grouping

A set of mutual relationships between all pairs of folders so their collective contents are equivalent.

 

Definitions

Term

Definition

Relationship

A relationship is an association between a single source folder and a single destination folder where the items in the source folder are to be included in the destination folder.  Original items in the source folder are said to be subject to the relationship.

Source

A folder defined by the relationship as having items to be copied to a destination folder.  The folder may be in the Outlook public folder list or a folder in a user's private mailbox.  It may be a calendar, contacts or tasks folder; for Enterprise edition users it may also be a posts/mail folder.

Destination

The destination folder is the recipient of the items from the source folder of the relationship.  It may be any of the kinds of folder described above, but it must be of the same item type (calendar, contacts, tasks) as the source folder.

Original

Items in the folders which were not created by Add2Exchange, namely items either created by a user or imported into Outlook.

Copy

Items created by Add2Exchange.  These are marked with a special tag visible only to Add2Exchange.  They are never subject to being copied to another folder by Add2Exchange.  Because of this difference between copies and originals, you want to take care to not move these items into the source folder of another relationship.  They look like items that can be copied by Add2Exchange but they are not.

Replica

Another term for copy.

Side-copy

A copy which has been modified by a user and, because of such, is no longer synchronized with the source.  This is called a side-copy because a new copy of the original is generated alongside this copy.

Synchronization

The process of copying entire items or just changes to items from a source to a destination, or if configured in a two-way model, copying changes in either direction.

Replication

The process of copying items or changes to items, also another term for synchronization.  Sometimes applied to just the initial copying of an item.

Rule

A configuration option in the relationship that defines how the relationship behaves.  The rule defines the behavior in response to a significant event, such as a user editing or deleting an item subject to the relationship.

Public

Term applied to items or folders that exist in Outlook's public folder list.

Private

Term applied to items or folders that exist in a user's mailbox.

One-way

Synchronization where the original (source) item is not changed when a copy is modified or deleted.

Two-way

Synchronization where the original (source) item is kept in sync with modifications to a copy.  Two-way synchronization may or may not allow a source item to be deleted when a copy is deleted, depending on the relationship configuration.

Mutual

Synchronization where two relationships between a pair of folders give them an equivalent set of items.

Module

The part of Add2Exchange which processes folders of a particular item type.  There are separate calendar, contacts and task modules in Add2Exchange.  Synchronization of different modules may be run on different schedules.

Publication

A model of synchronization that performs a one-way push of items from a single source to one or more destinations.  Changes to the copies in destination(s) are not synced to the source.  The original contents of the destination(s) are also not synced to the source.

Participation

A model of synchronization that performs a two-way synchronization of items from a single source to one or more destinations.  Changes to either the original items in the source or the copies in destination(s) are synced both ways.  The original contents of the destination(s) are not synced to the source.

Grouping

A model of synchronization between a set of folders where the contents of each folder are replicated to every other folder.  This makes the contents of the folders equivalent.

Aggregation

A model of synchronization that performs a one-way push of items from multiple sources to a single destination.  Changes to the copies in the destination are not synced to the sources.

Processing Interval or Cycle

The time period between two synchronization processes of the same module (calendars, contacts or tasks) taking place.  Calendars, contacts and tasks are run on separate processing intervals.

Synchronization Window

In a calendar or task relationship, the set of dates where items are actively synchronized, usually based from today moving forward.  Appointments and meetings in the distant past are usually not synchronized.

Recurrence Cutoff

A date in the past which defined a cutoff for synchronization of recurring appointments or tasks.  Recurrences which begin prior to the cutoff date are not synchronized.  To synchronize a recurring item which began prior to this date, either the date needs to be changed through Global Options to be earlier than the start of the recurrence, or the recurrence needs to be changed to start after the cutoff date.

Event

The occurrence of something significant to synchronization, such as the editing or deletion of an item subject to a relationship.

Trigger

Another term for event.  Also sometimes used as a term for the rule triggered by an event, such as the editing or deletion of an item subject to a relationship.

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