Map

In file transfer, a “map” is usually short for “transformation map“, which provides a standardized way to transform one document format into another through the use of pre-defined document definitions.

See “transformation map” for more information.

Mapper

In file transfer, a “mapper” is a common name for a “transformation engine” that converts documents from one document definition to another through “transformation maps“.

See “transformation engine” for more information.

MD4

MD4 (“Message Digest [algorithm] #4″) is best known as the data integrity check standard (a.k.a. “hash”) that inspired modern hashes such as MD5, SHA-1 and SHA-2.  MD4 codes are 128-bit numbers and are usually represented in hexadecimal format (e.g., “9508bd6aab48eedec9845415bedfd3ce”).

Use of MD4 in modern file transfer applications is quite rare, but MD4 can be found in rsync applications.  A variant of MD4 is also used to tag files in eDonkey/eMule P2P applications.

Although MD4 is considered a “cryptographic quality” integrity check (as specified in RFC 1320), it is not considered a secure hash today because it is possible for an attacker to create bad data that bears the same MD4 code as a set of good data.  For this reason, NIST does not allow the use of MD4 in key U.S. Federal Government applications.

BEST PRACTICE: Modern file transfer deployments should use FIPS validated SHA-1 or SHA-2 implementations for integrity checks instead of MD4.

MD5

MD5 (“Message Digest [algorithm] #5″) is the most common data integrity check standard (a.k.a. “hash”) used throughout the world today.  MD5 codes are 128-bit numbers and are usually represented in hexadecimal format (e.g., “9508bd6aab48eedec9845415bedfd3ce”).

MD5 was created in 1991 as a replacement for MD4 and its popularity exploded at the same time use of the Internet did as well.  MD5′s use carried over into file transfer software and its use remains common today (e.g., FTP’s unofficial “XMD5″ command).

Although MD5 is considered a “cryptographic quality” integrity check (as specified in RFC 1321), it is not considered a secure hash today because it is possible for an attacker to create bad data that bears the same MD5 code as a set of good data.  For this reason, NIST has now banned the use of MD5 in key U.S. Federal Government applications.

BEST PRACTICE: Modern file transfer deployments should use FIPS validated SHA-1 or SHA-2 implementations for integrity checks instead of MD5.  However, FTP software that supports the XMD5 command can be useful to provide backwards compatibility during migration to stronger hashes.

MDN

An MDN (“Message Disposition Notification”) is the method used by the AS1, AS2 and AS3 protocols (the “AS protocols”) to return a strongly authenticated and signed success or failure message back to the senders of the original file.  Technically, MDNs are an optional piece of any AS protocol, but MDNs’ critical role as the provider of the “guaranteed delivery” capability in all of the AS protocols means that MDNs are usually used.

Depending on the protocol used and options selected, the MDN will be returned to the sender in one of the following ways:

Via the same HTTP/S stream used to post the original file: AS2 senders may request that MDNs are sent this way.  This type of transfer is popularly called “AS2 with synchronous MDNs” (or “AS2 sync” for short).  When small files are involved, this type of transfer is the fastest AS protocol transfer currently available.

Via a separate HTTP/S stream back to the sender’s server: AS2 senders may request that MDNs are sent this way.  This type of transfer is popularly called “AS2 with ansynchronous MDNs” (or “AS2 async” for short).  This type of transmission is slightly more resiliant to network hiccups and long processing turnaround times of large files than “AS2 sync” transmissions.

Via email: All AS1 MDNs are returned this way.  AS2 aysnc senders may also request that MDNs are sent this way.

Via FTP: All AS3 MDNs are returned this way.

Full MDNs (the signed responses) are sometimes retained by the sender and/or recipient as irrefutable proof of guaranteed delivery.  The use of X.509 certificates to authenticate and sign both the original file transmission and the MDN receipt often allows MDNs to rise to the level of legally binding nonrepudiation in many jurisdictions.

Message-Oriented Middleware

Message-Oriented Middleware (“MOM”) is software that delivers robust messaging capabilities across heterogeneous operation systems and application environments.   Up through the early 2000′s MOM was the backbone of most EAI (“Enterprise Application Integration”) inter-application connectivity.  Today, that role largely belongs to to ESB (“Enterprise Service Bus”) infrastructure instead.

 

 

Metadata

In file transfer, “metadata” usually refers to information about files moved through a file transfer system.  Examples of metadata include usernames of original submitter, content types, paths taken through the system so far and affirmations of antivirus or DLP checks.

Metadata such as suggested next steps is often submitted to file transfer applications in control files. However, most metadata is typically collected during a file’s flow through a file transfer system.  (All the metadata examples above are examples of passively collected metadata.)

File transfer applications often use metadata in their configured workflows to make runtime decisions.  (e.g., A workflow engine may be configured to send files from two different users to two different destinations.)

Metadata is often stored in the status, workflow and log databases used by file transfer applications.   When these data stores are proprietary or inaccessible integrating metadata from multiple applications can be challenging.

Explicit file attributes such as file size, file name, current location on disk and current permissions are not typically considered metadata.  The reason these attributes are not considered metadata is because they are required by almost every operating system; by definition metadata is extra data used to provide additional context for each file.

Microsoft Cluster Server

Microsoft Cluster Server (“MSCS”) is a Microsoft-specific high availability technology that provides a failover capability to pairs of its servers.

Like “web farm”, the term “clustering” is a vendor-neutral term, but every vendor that does clustering does it a little differently, and provides cluster services at different levels (typically at the hardware, OS or application levels).

Microsoft clusters using a specific combination of hardware (e.g,. quorum disk with fiber attachment) and operating system (e.g., Microsoft 2008 Enterprise), and it has decided to name those particular bundles – the only bundles that support clustering – as “Microsoft Cluster Server”.

See also “Web Farm“.

BEST PRACTICES: Explicit support for MSCS is no longer critical for file transfer technology.  Most managed file transfer applications already have application-level clustering support, use web farms or can be failed over in virtual environment using technology like VMware vMotion.

Middleware

Middleware is a software architecture concept that refers to integration of disparate applications to facilitate reliable communication.  Middleware frequently relies on encapsulating inter-application communications in the concept of an “message”, and often has the ability to queue or perform optimized delivery or copying of messages to various applications.

Common types of middleware include EAI (“Enterprise Application Integration”) middleware such as ESB (“Enterprise Service Bus”) or the older MOM (“Message-Oriented Middleware”).

File transfer applications are themselves often used as middleware, helping to facilitate bulk data transfers between applications using standards such as FTP.  Managed file transfers often include the ability to perform some intelligent routing of data and sensitivity to particular transmission windows set by the business.

MOM

In the context of file transfer, MOM stands for “Message-Oriented Middleware“, which is software that delivers robust messaging capabilities across heterogeneous operation systems and application environments.

 

MSCS

MSCS is an abbreviation for “Microsoft Cluster Server“, which is a Microsoft-specific high availability technology that provides a failover capability to pairs of its servers.

   
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