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Converged Communication Server
Converged Communication Server
The Avaya Converged Communications Server (CCS) is dedicated to performing proxy,
registrar, presence, and licensing functions associated with SIP applications, such as Instant
Messaging and SIP trunking. SIP-enabled endpoints need only register with the CCS; they can
be but do not need to be managed by Avaya media servers. In addition, the CCS supports the
SIP-enabled Instant Messaging application between users of IP Softphone R5.x client software;
the IM clients can be, but do not need to be managed by Avaya media servers.
A SIP proxy server serves as a routing server for SIP requests from clients or other proxy
servers. The proxy server receives signaling requests from endpoints or proxy servers, stays in
the signaling path for the duration of the transaction, and forwards requests to the destination
endpoint or to a server that is closer to the final destination.
A SIP registrar is a server to which SIP endpoints register, and which maintains the status of
such endpoints. The SIP registrar is also responsible for binding a user's "well-known" URI (e.g.
wcoyote@acme.com) with a URI "closer" to the endpoint (e.g.
wcoyote@roadrunner1.acme.com), and for making that information available to the SIP location
service.
As defined by the IETF, presence (or presence information) is the indication of whether a user is
capable or willing to take part in a communication session. Presence may also include contact
or address information for the means of joining the communication session, preferences about
which means to use and when, and state about availability at those means (for example, station
on-hook or off-hook).
A presence event occurs when users log in or out of a telephone, change their preferences
about reachability at some location, such as a phone or pager, or change their status at some
location. More generally, a presence event is any event which changes the current presence
information.
A presence server is a server that collects presence information from endpoints, and makes the
presence information available to other entities (endpoints or servers). Presence and presence
servers are useful when trying to send a message to a user, rather than an endpoint. Presence
information allows the message to be routed to the endpoint "closest" to the user, whether at his
desk, in a conference room, on a mobile phone, or at home.
By combining SIP proxy, registrar, presence, and licensing in a single CCS server, Avaya
makes it easy for customers to take advantage of SIP in a straightforward manner without
requiring a significant investment in additional hardware.
In release 2.2, CCS adds support for high availability features, direct IP-IP shuffling between
SIP devices, SNMP support, and several security enhancements. CCS now supports 1+1
(active/standby) redundancy by using a shared virtual IP address and replicating state updates
between servers. Security enhancements include TLS-protected administration web pages,
digital certificates signed by the Avaya Root CA, Linux PAM support, and per-call SIP digest
authentication.
Issue 3.4.1 June 2005
101
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