Handshaking Protocol Modules

Home Project Closed Site Index News Recent Old Download Documents User Docs Development Introduction to ANet High-Level Design Run-Time Wrapper Client Connection Modules Data Transformation Modules Client SDK Cluster Group Modules Cluster Filter Modules Core Modules Handshaking Protocol Modules Packet Protocol Modules Connection Protocol Modules Bandwidth Manager Module Document Type Definition (DTD) Low-Level Design Protocol Specifications Task List Development Roadmap Other Docs Development Mailing Lists Contacting Us

PROJECT CLOSED

by Benad

The goal of the Handshaking Protocol Modules is to provide and maintain network connections to the Core Modules[1].

Table of Contents

• Design
  • Role of the Handshaking Protocol Modules
  • Input/Output for the Handshaking Protocol Modules
  • Connections
• Implementation Notes
• DTD

Design

Role of the Handshaking Protocol Modules

The Handshaking Protocol Modules are there to provide an abstraction of network connections. From the point of view of the Core Modules, connections are identified by an ID, and Input/Output is done through buffers that will be given to the Handshaking Protocol Modules. So, it is up to the Handshaking Protocol Module to provide the IDs and to figure out to what actual protocol they point to.

Thus, it is up to the Handshaking Module to initaite and close the actual connections. This includes the need to exchange information about the distribution protocol itself, including the information taken from the Filter Modules[2], hence the name "Handshaking Protocol".

It is important to note that it is not the role of the Handshaking Protocol to define how the connections are identified, both internally and in the configuration file. This is required, as many modules require to "know" what the connections are, without forcing them to "know" how the Hanshaking Protocol works.

Input/Output for the Handshaking Protocol Modules

Basically, the entire Input and Output is in the parsed configuration file[3]. The goal of the Hanshaking Protocol is to try to make connections as in the current configuration, and update the configuration to the current state of the connections (Open, Closed and On Hold[1]).

The current configuration also contains Memory Tags[3] for both Input and Output buffers for each connection. This might be needed for some Handshaking Protocols, though it is not the goal of the Handshaking Protocol to produce or filter data in those buffers.

Connections

So, what the connections consist of? To be able to properly identify and use a connection in ANet, here's what is needed.

• Connection ID: The unique ID that identifies this connection. Read only for all modules except the Handshaking Modules.
• Connection State: The current state of the connection. It can be "Open", "Closed" or "On Hold"[1].
• Input Buffer: A buffer of AEPs that came from the network on that connection.
• Output Buffer: A buffer of AEPs that will go to the network on that connection.
• Packet Protocol Name: The name of the Packet Protocol Module for that connection.
• Connection Protocol Name: The name of the Connection Protocol Module for that connection.
• Network ID: A unique identifier for the Connection Protocol that identifies the other end of the connection. For example, using TCP/IP[4], this is the IP address and port of the other computer.
• Subnet: This is the "network subnet" of the connection. Usually, this has a value representing "the internet". This is useful only when the Connection Protocol can handle routers and "knows" the difference between an internet and an intranet connection.

All of these values will be inside the current configuration settings.

Implementation Notes

• Use the "On Hold" status value when you are in the process of starting or resuming a connection. Otherwise, the rest of the deamon and the clients will keep sending data to the connection.
• You're not forced to send the security rules to establish a connection, though not doing so might result in unexpected disconnections, instead of initially deciding to not connect because the current security rules cannot be followed.
• You can write the Handshaking Protocol to ask, before the beginning of the connection, a list of the Network IDs that are connected to the other side of the connection to do some "network discovery", though it is not required. If you do that, you can implement a connection system similar to Gnutella[5] or Freenet[6].

DTD

See the complete DTD for more information.

<!-- Handshaking Protocol. Contains a list of inital connections
(live connections once opened) -->
<!ELEMENT HandshakingProtocol (Connection)*>
<!ATTLIST HandshakingProtocol %moduleName; %args; %security;
          minConnections CDATA "0"
          maxConnections CDATA "-1">

References

About the references...

Last update for this document: September 30, 2001, at 18:42:46 PST