CA Gateway Update

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CA Gateway Update

• Ralph Lange, BESSYKen Evans Jr., APSJeff Hill,
  LANL

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Overview

• As well CA server as CA client
• Usually runs on workstation with multiple network
  interfaces
• Connects and separates networks in terms of CA
  connections
• May use channel aliases (e.g. prefixes)
• Caches data
• Keeps connections alive
• Watchdog mode restarts on core dump

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CA Proxy Gateway

• Allows CA between networks configurable through
  regular expression filters and CA access security.

CA Clients
CA Gateway
CA Servers
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CA Proxy Gateway

• Clients point to one proxy that distributes the
  data with minimal impact on the private parts.

CA Clients
CA Gateway
CA Servers
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Caveats

• The Gateway always introduces a non-scalable
  bottleneck.
• A heavily loaded Gateway is a CPU and memory
  consuming application that usually will add
  overhead to the system.
• Bad configuration (too loose) may put more load
  on the precious side instead of shielding the
  IOCs.

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Recent Developments

• Gateway 2.0 (built against EPICS base 3.14.2) is
  complete and working.
• More bugfixes in the Gateway, GDD, CAS / CAC,
  important performance improvements.
• CAput logging feature (same as on IOC).
• Work on documentation (user manual) started.
• BUT...
• Still some crashes (bad) and brain-dead hang
  situations (much much worse).
• Not yet officially released.

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Next Steps

• Mid-July Jeff and Ken will try to fix the hang
  problems.
• After that Independent of their results a
  release of the Gateway will be published.
• Either a beta releasebad but still better than
  the old 3.13.2 based Gateway.
• Or a stable 2.0quite good, but still bad, with
  lots of room for improvements

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Ideas

• All the nice ideas for improvements
• will be postponed until stable operation of the
  Gateway is achieved.

• New hierarchical configuration file format to
  improve performance (XML format?)
• New configurable watchdog (steal from Channel
  Archiver)
• Better code documentation (using Doxygen?)
• CMLOG interface
• Provide some tabular usage and statistics info as
  web page
• Use Data Access (new data object) instead of GDD