Nortel Networks 1000S - Manual (Page 44)

Page 44 of 44 Configuration options
553-3031-010 Standard 3.00 August 2005
The survivable MG 1000S (Alternate Call Server) IP address must be on the
same ELAN subnet as the Call Server. If the MG 1000S is on a physically
different subnet, such as in a different building, then you can use VLANs to
keep IP addresses on the same logical subnet. For further implementation
details, refer to Data Networking for Voice over IP (553-3001-160).
If there are different nodes in different MG 1000S, then the nodes can be
configured to register to different Alternate Call Servers. This concept is
desirable for optimizing system reliability to best deal with possible system
outages. Associate each IP telephony node with an appropriate (for example,
co-located) Alternate Call Server.
If the node IDs are configured using the guidelines for the ‘Enhanced
Redundancy for IP Line Nodes’ feature, then the IP Phones can register (if
needed) to an alternate node on an MG 1000S Expander. This further
improves the survivability of the IP Phones by allowing them to register to a
different node should a system outage occur on their primary node's
MG 1000S.
Refer to IP Line: Description, Installation, and Operation (553-3001-365)
for a description of the Enhanced Redundancy for IP Line Nodes feature.