HPE FlexNetwork MSR Series User Manual

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again. The subsequent procedure is the same as that for calling a called UA directly or for calling a
proxy server.
Location server
A location server is a device that provides UA information to proxy and redirect servers. It retains UA
information received by a registrar. The location server and registrar can locate on the same server
as two logical components or locate on different devices.
Registrar
A registrar receives UAs' registrations. The registration information (for example, the local telephone
number) is usually stored on the location server for future retrieval. The location server and the
registrar are both logical components and are usually co-located.
Functions and features of SIP
Functions
SIP supports five basic functions:
• Locating called SIP endpoints—The most powerful function of SIP. For this purpose, SIP can
use the registration information of SIP endpoints on the registrar. In addition, it can improve its
user location service by using other location services provided by the DNS and LDAP.
• Determining user availability—Makes sure whether a called endpoint can participate in a
session. SIP supports multiple address description and addressing styles, SIP-URI (for
example, SIP: 123456@172.18.24.11), Tel-URL (for example, Tel: +1312000), and SIPS-URI
(SIPS: 123456@172.18.24.11). Therefore, a SIP caller can identify whether a callee is attached
to a PSTN network by callee's address, and then initiate and set up the call to the callee through
the gateway connected to the PSTN.
• Determining user capabilities—Determines the media type and media parameters of a called
endpoint. In a message exchange process, each SIP endpoint sends such information in
messages so that all other participants can learn about its capabilities.
• Setting up a session, or session parameters, at both callee and caller sides—Two parties
can select the appropriate capabilities for session setup through negotiation about media type
and media parameters to be used.
• Managing sessions—Manages sessions by modifying session parameters or terminating
sessions.
Features
The following are the features delivered by SIP:
• Open standards. It can accommodate new functions, products, and services introduced by
different service providers.
• Flexible configuration. It accommodates a wide range of dialup, wire, and wireless devices,
allows highly flexible configurations, and can work with other systems.
• Scalable system. The system allows expansion as enterprises grow.
• Support to remote users. With SIP, an enterprise network can extend to all its users, wherever
they are.
• Consistent communication method. Management becomes easier as the result of consistency
in dialup mode and system access method used by branches, SOHOs, and traveling personnel.
• Quick launch. The system can be updated quickly to accommodate new branches and
personnel, and changes resulting from job rotation or relocation.
• Easy to install and maintain. Nonprofessional individuals can install and maintain SIP systems.

HPE FlexNetwork MSR Series Specifications

General

Brand	HPE
Model	FlexNetwork MSR Series
Category	Network Router
Language	English