CounterPath Bria 4 Configuration Guide - Enterprise Deployments - Manual (Page 16)

CounterPath Corporation
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2.21 Presence
Triggers for Presence Subscriptions
Presence subscriptions are started in the following cases:
• If the user creates or modifies a contact and adds an address in the Softphone field, then Bria subscribes to
that address for presence if:
• The domain of the address matches the domain of an existing, enabled SIP account.
• And that SIP account is set up for IM/Presence (“Account Usage” on page 3).
By default, the subscription is handled in peer-to-peer mode. You can change the mode to Presence Agent
mode by setting in the Presence topic in the Bria 4 Settings reference documentation.
• If the user creates or modifies a contact and adds an address in the Instant Message field, then Bria
subscribes to that address for presence if:
• The domain of the address matches the domain of an existing, enabled XMPP account.
• And the user clicks the Enable XMPP Presence button on the Contact Profile.
The subscription is handled by the XMPP server; no setup is required in Bria.
How SIP Presence Subscriptions are Handled
Bria supports IETF standard SIMPLE presence using a SIP subscription to the presence event package. Bria
supports the SIMPLE rich presence extensions (RPID - RFC 4480), which allows detailed presence information
to be conveyed in a standards-compliant manner.
Peer-to-Peer Presence Mode
In peer-to-peer presence modes, the clients in the network send SIP SUBSCRIBE and NOTIFY messages
directly to one another. The Bria that receives the request consults the local copy of the privacy rules to
determine whether a rule already exists. If no rule exists for the other party, then the request is deferred to the
user through a popup; the user’s action typically results in a privacy rule being created. The amount of SIP
message traffic on the network can be substantially larger than in presence agent mode.
Presence Agent Mode
In presence agent mode, when Bria is first started, it sends presence information to the network using the SIP
PUBLISH mechanism (RFC 3903). Bria still sends a SUBSCRIBE message per contact found in the contact list
when it is first started, but the presence agent will simply return a NOTIFY message with the current presence
document on behalf of the contact that was subscribed to. As well, Bria subscribes to the presence info (winfo -
RFC 3857, 3858) event package which will inform the user when they have to make a presence authorization
decision.