X-400 Message Handling Protocol X-500 Directory Access Protocol

Some one ask me that how we will remember the x-400(Message Handling Service Protocol) x-500(Directory Access Protocol (DAP)) in data communication so we ask this question to our teacher and he replied back to us in this manner.

X-400 Message Handling Protocol X-500 Directory Access Protocol

There are many application services such as electronic mail, file transfer access and management etc which are available on Application Layer as this layer directly interacts with the user. So, Message handling service and File directory service are also two services from bundle of those services, available on Application Layer. You may remember these as examples of services available on Application Layer.

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Read More About X400 Message Handling Service Protocol

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An X400 referred technically as recipient or originator or Address. Basically have 2 purposes.

• Identification of Mailbox – either the recipient or sender.
• Identification of Global Domain – where a given mailbox is located.

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Read More About X500 Directory Access Protocol

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X500 concept is basically single Directory Information Tree (DIT), a hierarchical organization of entries which are distributed across one or more servers, called Directory System Agents (DSA)
The protocols defined by X.500 include

• DAP (Directory Access Protocol)
• DSP (Directory System Protocol)
• DISP (Directory Information Shadowing Protocol)
• DOP (Directory Operational Bindings Management Protocol)