Cisco Cisco Expressway Maintenance Manual
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Iptablesacceptedrule
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Iptablesrule
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License
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Links
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Mediastatistics
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NetworkInterface
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NetworkLimits (experimental)
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Ntpcertificates
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Options
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PhonebookServer
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Pipes
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Policy
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PortUsage
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ResourceUsage
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Resourceusage
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SIP
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SipServiceDomains
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SipServiceZones
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SystemMetrics
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SystemUnit
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TURN
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Teststatus
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Time
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Traversalserverresourceusage
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Tunnels
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Warnings
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XMPP
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Xcps2s
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Zones
External Policy Overview
The Cisco Expressway (Expressway) supports CPL (Call Processing Language) for implementing complex policy
decisions. CPL is designed as a machine-generated language and is not immediately intuitive; while the Expressway
can be loaded with CPL to implement advanced call policy decisions, complex CPL is difficult to write and maintain.
decisions. CPL is designed as a machine-generated language and is not immediately intuitive; while the Expressway
can be loaded with CPL to implement advanced call policy decisions, complex CPL is difficult to write and maintain.
The Expressway’s external policy feature allows policy decisions to be taken by an external system which can then
instruct the Expressway on the course of action to take (such as whether to fork a call and so on). Call policy can now
be managed independently of the Expressway, and can implement features that are unavailable on the Expressway.
The external policy server can make routing decisions based on data available from any source that the policy server
has access to, allowing companies to make routing decisions based on their specific requirements.
instruct the Expressway on the course of action to take (such as whether to fork a call and so on). Call policy can now
be managed independently of the Expressway, and can implement features that are unavailable on the Expressway.
The external policy server can make routing decisions based on data available from any source that the policy server
has access to, allowing companies to make routing decisions based on their specific requirements.
When the Expressway is configured to use an external policy server the Expressway sends the external policy server a
service request (over HTTP or HTTPS), the service will send a response back containing a CPL snippet which the
Expressway will then execute.
service request (over HTTP or HTTPS), the service will send a response back containing a CPL snippet which the
Expressway will then execute.
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Cisco Expressway Administrator Guide
Reference Material