Instruction manual

Internet Protocol (IP)
Issue 4 May 2003 141555-233-767
Alternate gatekeeper and registration
addresses
When an IP endpoint (including softphones, IP phones, and Avaya R300) registers
with the switch, the switch sends back an IP registration address. The switch sends
a different IP address for each registration according to a cyclic algorithm.
If registration with the original C-LAN circuit pack IP address is successful, the
switch sends back the IP addresses of all the C-LAN circuit packs in one network
region, not including interconnected regions. These C-LAN addresses are called
gatekeeper addresses. These addresses can also be used if the call signaling on the
original C-LAN circuit pack fails.
NOTE:
On switches using the LAN region based on IP Address feature, it’s likely
that the network region number assigned to an IP phone would be different
from the network region number of the TN799 that the phone is registering
through. That difference would mean the list of TN799 addresses in the
same network region as the IP phone would be empty. The alternate
gatekeeper feature would send a blank list to the IP phone.
To prevent that from happening, an IP terminal registers with
Communication Manager. Communication Manager then sends to the
endpoint the IP addresses of the CLANs in the same region as the terminal,
followed by network regions interconnected with the network region of the
terminal.
If the network connection to one C-LAN circuit pack fails, the IP endpoint
re-registers with a different C-LAN. Alternate gatekeeper and registration
addresses, and C-LAN circuit pack load sharing, spread IP endpoint registration
across more than one C-LAN circuit pack, increasing performance and reliability.
Classless Interdomain Routing (CIDR)
CIDR is a redefinition of the subnet mask, allowing for the aggregation of
contiguous classful networks under a single network definition. This allows for
more efficient routing table management when administering IP address on
Communication Manager.
Multiple network regions per C-LAN
See ‘‘Multiple network regions per C-LAN’’ on page 167.