Cisco Cisco Unified SIP Proxy Guia De Resolução De Problemas
The network contains a logical collection of local interfaces that are treated the same for general
routing purposes.
routing purposes.
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SIP messages, upon arrival, are associated with the network on which the messages are received
(incoming network).
(incoming network).
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The outgoing network is set as a part of the routing logic of CUSP and the messages are
forwarded/sent to the set network.
forwarded/sent to the set network.
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Each SIP network has these properties:
Listen Points − can have multiple listen points per network
♦
Server Groups − elements in the Server Groups (SGs), such as Cisco Unified
Communications Manager (CUCM) clusters
Communications Manager (CUCM) clusters
♦
SIP Timers − retransmission counts
♦
Ping Options − monitors the health of each element in the SG and is configured per network
♦
Record Route − call states are not stored because there are routing tables
♦
Via Header Stripping − in order to hide the topology
♦
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Here is an example:
sip listen Net−PSTN udp 14.128.100.169 5060
!
sip network Net−PSTN standard
no non−invite−provisional
allow−connections
retransmit−count invite−client−transaction 3
retransmit−count invite−server−transaction 5
retransmit−count non−invite−client−transaction 3
retransmit−timer T1 500
retransmit−timer T2 4000
retransmit−timer T4 5000
retransmit−timer TU1 5000
retransmit−timer TU2 32000
retransmit−timer clientTn 64000
retransmit−timer serverTn 64000
tcp connection−setup−timeout 1000
udp max−datagram−size 1500
end network
!
Triggers
This section describes what triggers are and how they are used.
A trigger is a set of conditions used in order to determine which routing and normalization policy is
applied to an SIP request.
applied to an SIP request.
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A trigger condition defines matching rules against certain headers or fields within an SIP message,
network, and transport type (UDP, TCP, Transport Layer Security (TLS)).
network, and transport type (UDP, TCP, Transport Layer Security (TLS)).
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A trigger is evaluated as either true or false for each received request.
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If the condition is true, then preset behaviors are invoked.
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The AND operation is achieved by specifying headers or fields in a single trigger−condition
command.
command.
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The OR operation is achieved with several trigger−conditions, each identified by a sequence number.
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The conditions are evaluated in ascending order based on sequence number.
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The mid−dialog condition is the first one, so that the policy step is skipped for mid−dialog messages.
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Here is an example:
trigger condition TC−from−CUCM
sequence 1