ralph lange: ca gateway update ca gateway update ralph lange – epics collaboration meeting march...
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Ralph Lange: CA Gateway Update What is a CA Gateway? An application that forwards connections between CA clients and servers.TRANSCRIPT
Ralph Lange: CA Gateway Update
CA Gateway Update
Ralph Lange – EPICS Collaboration Meeting March 2008 @ SSRF
Ralph Lange: CA Gateway Update
Credits: Main Authors and Contributors
Channel Access DevelopmentJeff Hill (LANL)
CA Gateway Development1996 Jim Kowalkowski (APS)
Janet Anderson (APS)1999 Ken Evans (APS)2000 Ralph Lange (BESSY)2002 Ken Evans (APS)
Jeff Hill (LANL)2007 Gasper Jansa (cosylab)
Dirk Zimoch (SLS)
Ralph Lange: CA Gateway Update
What is a CA Gateway?
An application that forwards connections between CA clients and servers.
Ralph Lange: CA Gateway Update
It's a Gateway.
Allows CA between networks – configurable through regular expression filters and CA access security.
Gateway
CA Clients
CA Servers (IOCs)
Ralph Lange: CA Gateway Update
It‘s a Proxy.
Clients point to one proxy that distributes the data with minimal impact on the IOCs.
CA Clients
CA Servers (IOCs)
Gateway
Ralph Lange: CA Gateway Update
Overview: Key Features
• 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. add prefixes)• May cache data (CA get is answered by the gateway)• Keeps IOC-side connections alive• Watchdog mode restarts on core dump• Provides statistics channels to allow monitoring
Ralph Lange: CA Gateway Update
CA Gateway Configuration: Symmetric
Each network sees the channels of all other networks.Gateways may run on a single host with multiple (virtual) interfaces.
Ralph Lange: CA Gateway Update
CA Gateway Configuration: Reverse Gateway
All networks see channels in network Z.The reverse Gateway forwards Gateway statistics.
Ralph Lange: CA Gateway Update
CA Gateway Configuration: Alias Gateway
The Gateway provides aliases for channel names.
Ralph Lange: CA Gateway Update
Recent CA Gateway Changes
• Option to disable cache (forward each CA get to the IOC)• Transparently works for Alarm Handler and Archiver connections• Option to use Perl regexp instead of GNU regexp (allows easy
negation of regexp)• Numerous bugfixes (beacons missing, Gateway hangs)
The CA Gateway is available from the EPICS extensions page.