Avaya 4600 Series - Manual (Page 38)

4600 Series IP Telephone LAN Administrator’s Guide
DHCP
4-8
MCIPADD={list of DNS names},MCPORT=yyyy,TFTPSRVR={list of DNS
names},TFTPDIR=
Where xxx.xxx.xxx.xxx is one or more IP addresses for DEFINITY
®
/MultiVantage TM
CLAN IP boards, yyyy is the DEFINITY/MultiVantage CLAN port (1719),
zzz.zzz.zzz.zzz is one or more IP addresses for TFTP servers, and is the
location of the location of the upgrade script and application files on the TFTP server
as entered in Table 4-2, items 4, 5, 2, and 7, respectively. Each list may contain up to
127 total ASCII characters, with IP addresses separated by commas with no
intervening spaces, and with quotes on either end (see the example in the NOTES
below). If you use DNS, note that the system value DOMAIN will be appended to the
IP addresses you specify. If DOMAIN is null, the DNS names must be fully qualified.
See Administering Options for the 4600 Series IP Telephones on page 4-24.
In configurations where the upgrade script and application files are in the
default directory, the TFTPDIR= should not be used.
You do not have to use Option 176. For example, if the DNS server is
specified in Option 6, and the Domain Name is specified in Option 15, you
can use the configured names "AvayaTFTPServer" and "AvayaCallServer"
for TFTPSRVR and MCIPADD, respectively.
The Call Server Name, TFTP Server Name, and SMTP Server Name must
each be no more than 32 characters in length.
■ Examples of good DNS administration include the following:
- Option 6: "aaa.aaa.aaa.aaa"
- Option 15: "dnsexample.yourco.com"
- Option 66: "tftpserver.yourco.com,zzz.zzz.zzz.zzz"
- Option 176: "MCIPADD=xxxx.xxx.xxx.xxx"
■ Depending on the DHCP application you choose, you should be aware of
the fact that the application most likely will not immediately recycle expired
DHCP leases. An expired lease may remain reserved for the original client
for a day or more (for example, Windows NT DHCP reserves expired
leases for about one day). The intent of this reservation period is to protect
a client’s lease in case the client and the DHCP server are in two different
time zones, the computers’ clocks are not in synch, or the client is not on
the network when the lease expires.
■ The implication of this fact may be seen in the following example: Assume
2 IP addresses (hence 2 possible DHCP leases) and 3 IP telephones, two
of which are using the 2 available IP addresses. When the lease expires
for the first two telephones, the third will not be able to get a lease (even if
the other two telephones have been removed from the network), until the
reservation period expires.