Avaya Media Gateway G700 사용자 설명서

A DHCP server assigns IP addresses to IP endpoints dynamically. Avaya IP phones perform a 
DHCP discover request to receive an IP address, as well as receive parameters necessary to 
function correctly. These parameters include the location of the call control server, the location 
of the TFTP server, as well as the directory on the TFTP server from which the phone receives 
its upgrades. 

When preparing a DHCP server to work with Avaya IP phones, there is an option that must be 
administered to allow the Avaya phone to receive the DHCP offer. This option is 
“site-specific-option-number” (sson) 176. Different DHCP servers allow for this administration in 
different ways, but the sson option must be mapped to 176. Then the option can be set up to 
send the information desired to the Avaya phones for the intended activity.

The sson option sends a string that includes the IP address of the Avaya Call Controller with 
which the phone will register (“MCIPADD=www.xxx.yyy.zzz”). In an S8400, S8500, or 
S8700-series system, this can be a CLAN address; in an S8400 or S8500, this can also be the 
IP address for the server’s port that is enabled for processor ethernet; in an S8300 system, this 
is the IP address of the S8300. Multiple addresses can be administered to allow for LSP 
failover. The second address in the MCIPADD list may be an IP address for a second CLAN 
board or an LSP. If a second CLAN board is used, then the third address must be the LSP, and 
any subsequent addresses should be alternate LSPs. Local LSPs should appear first in the list, 
with remote LSPs later in the list as possible back ups.

If an IP phone looses its connection to the primary controller, it will try to register with an LSP 
associated with its network region (as defined on page 3 of the IP Network Region form). 
However, if the phone resets, it looses this information and goes to the DHCP server for a 
controller. If the only controller in the MCIPADD list is the primary controller, and if the 
connection to the primary controller is down, the phone cannot register. Having an LSP in the 
MCIPADD list gives the IP phones an alternate controller in this situation.

Note:

It is strongly recommended that at least one LSP be administered in the 
MCIPADD list.

Also included in the sson option string is the “MCPORT=1719”. This is the port the phone will 
listen on for signalling traffic to the call controller. Next is the tftp server field. This field indicates 
to the phone where it is to receive firmware service packs, along with the tftp directory field.