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Setting JPIP Client Connection Properties

You can set the following client connection properties:

To set JPIP client connection properties:

  1. Open the Express Server Manager (see Accessing the Express Server Manager).
  2. Click Settings on the top navigation bar.
  3. Select JPIP on the left-hand navigation panel, then click Edit at the bottom of your screen.
  4. Enter or edit values for Disconnection Time, Maximum Client Connections, Maximum Open Sources, and other client connection properties, then click Save.
  5. If you have no further settings to edit, click Publish.

Remember that clicking Save in the workspace only temporarily saves your changes until you click Publish or Discard. Clicking Publish sends all edits on all the configuration pages to the live Express Server. Clicking Discard overwrites all pages of the workspace with the current live configuration.

Disconnection Time

The Disconnection Time property defines the number of seconds a client may be continuously connected before being automatically disconnected. By default this value is 6000 seconds or 100 minutes.

Maximum Client Connections

The Maximum Client Connections property defines the maximum number of client connections to be serviced at once. By default 1000 simultaneous client connections are permitted.

Maximum Open Sources

Express Server permits one open JPEG 2000 source file for each client connection. The Maximum Open Sources property can be used to reduce the number of source files allowed to be open simultaneously. Clients browsing the same image share a single open source file, which leads to a number of efficiencies. New client connections will be refused if the total number of open files would exceed the Maximum Open Sources limit, even if the total number of clients does not exceed the limit specified in the Maximum Client Connections property. If the Maximum Client Connections value is missing, the value specified by the Maximum Open Sources property also becomes the maximum number of connected clients.

By default, the total number of open source files permitted is 6000.

Initial Timeout

The Initial Timeout property specifies the amount of time in seconds to allow for the handshaking process used to establish persistent connection channels. Each time a TCP channel is accepted by Express Server, it allows this amount of time for the client to pass in the connection message. In the case of the initial HTTP connection, the client must send its HTTP GET request within the timeout period. In the case of persistent TCP session channels, the client must send its initial CONNECT message within the timeout period. The reason for timing these events is to guard against malicious behavior in denial of service attacks.

By default the Initial Timeout is 60 seconds, but this might not be enough when operating over very slow links.

Completion Timeout

The Completion Timeout property specifies the time within which the client must complete all persistent connections required by the relevant protocol, from the point at which it is sent the corresponding connection parameters. The server will not hold a session open indefinitely, since the client might terminate leaving the resources unclaimed.

By default the Completion Timeout is 60 seconds.

Connection Threads

The Connection Threads property specifies the maximum number of threads that can be dedicated to managing the establishment of new connections. The new connections are handed off to dedicated per-client threads as soon as possible, but connection threads are responsible for initially opening files and managing all tasks associated with delegating services to other servers. By allowing multiple connection requests to be processed simultaneously, the performance of the server need not be compromised by clients with slow channels.

By default the maximum number of connection management threads is 100.

Cache

The Cache property specifies the cache size per client attached to the same code-stream.

When serving a client, the JPEG 2000 source file is managed by a persistent Kakadu codestream object. This object loads compressed data on demand from the source file. Data which is not in use can also be temporarily unloaded from memory, so long as the JPEG 2000 code-stream contains appropriate PLT (packet length) marker segments and a packet order in which all packets of any given precinct appear contiguously. If you are unsure whether a particular image has an appropriate structure to permit dynamic unloading and reloading of the compressed data, try opening it with kdu_show and monitoring the compressed data memory using the appropriate status mode.

Under these conditions, the system employs a FIFO (first-in first-out) caching strategy to unload compressed data which is not in use once a cache size threshold is exceeded. The default cache size used by this application is 2 megabytes per client attached to the same code-stream. You may specify an alternate per-client cache size here, which may be as low as 0. Kakadu applications should work well even if the cache size is 0, but the server application may become disk bound if the cache size gets too small.