Multiple Svp Servers; The Timing Function - NEC SVP SERVER - INSTALLATION SETUP AND Installation And Setup Manual

2-2 SVP Server Overview
NOTE

Multiple SVP Servers

The Timing Function

IP multicast addresses are used by the MH120 Wireless Telephone Push to Talk
(PTT) feature. This requires that multicasting be enabled on the subnet used for the
Mobile Handsets, SVP Server, and telephony gateways.
Routers are typically configured with filters to prevent multicast traffic from flowing
outside of specific domains. The wireless LAN can be placed on a separate VLAN or
subnet to reduce the effects of broadcast and multicast traffic from devices in other
network segments.
Multiple SVP Server environments are those which have more than one
SVP Server in the same subnet in order to accommodate larger
systems and higher call capacity.
In a system comprised of multiple SVP Servers using an IP protocol,
a master SVP Server must be identified. The master SVP Server
must have a static IP address. The Wireless Telephones and the other
SVP Servers locate the master by using a static IP address, DHCP, or
DNS. The loss of a non-master SVP Server does not significantly affect
the operation of the remaining SVP Servers. However, the loss of
the master SVP Server results in a loss of all communication between
all of the SVP Servers. This also means that the loss of the master
SVP Server results in the loss of all active calls and Wireless Telephones
cannot check-in until communication with the master is reestablished.
In a UNIVERGE WL System Telephony Gateway system using multiple
SVP Servers, there is no "master" server.
In the UNIVERGE WL System Telephony Gateway environment, SVP
Servers provide the "timing" function for active calls. In multiple
SVP Server environments, the active calls are distributed across the
SVP Servers. In the IP PBX environment, SVP Servers provide both the
connection or "gateway" to the IP PBX for the Wireless Telephones and
the "timing" function for active calls. This "gateway" function is
distributed across the SVP Servers.
In both environments, the number of active SVP Servers is determined
dynamically. Whenever SVP Servers are added to or removed from
the system, the distribution of "timing" function for active calls, as well
as the "gateway" function in the IP PBX environment, is affected.
SVP Server Installation, Setup, & Maintenance Manual - Revision 1