Server Administration
-Option 57 - Maximum DHCP message size.
-Option 58 - DHCP lease renew time.
If not received or if this value is greater than that for Option 51, the default value of T1 (renewal timer) is used as per IETF RFC 2131, Section 4.5, listed in Related Documentation.
-Option 59 - DHCP lease rebind time.
If not received or if this value is greater than that for Option 51, the default value of T2 (rebinding timer) is used as per RFC 2131, Section 4.5
The 9600 Series IP Telephones do not support Regular Expression Matching, and therefore, do not use wildcards. For more information, see Administering Options for the 9600 Series SIP IP Telephones on page 73.
In configurations where the upgrade script and binary files are in the default directory on the HTTP server, do not use the HTTPDIR=<path>.
Avaya recommends that you administer DHCP servers to deliver only the options specified in this document. Administering additional, unexpected options might have unexpected results, including causing the IP telephone to ignore the DHCP server.
The SIP Proxy server name and HTTP server name must each be no more than 32 characters in length.
Examples of good DNS administration include:
-Option 6: “aaa.aaa.aaa.aaa”
-Option 15: “dnsexample.yourco.com,zzz.zzz.zzz.zzz”
-Option 42: "aaa.aaa.aaa.aaa"
Depending on the DHCP application you choose, be aware that the application most likely does not immediately recycle expired DHCP leases. An expired lease might remain reserved for the original client a day or more. For example, Windows NT® DHCP reserves expired leases for about one day. This reservation period protects a lease for a short time. If the client and the DHCP server are in two different time zones, the clocks of the computers are not in sync, or the client is not on the network when the lease expires, there is time to correct the situation.
The following example shows the implication of having a reservation period: Assume two IP Addresses, therefore two possible DHCP leases. Assume three IP telephones, two of which are using the two available IP Addresses. When the lease for the first two telephones expires, the third telephone cannot get a lease until the reservation period expires. Even if the other two telephones are removed from the network, the third telephone remains without a lease until the reservation period expires.
58 9600 Series SIP IP Telephones Administrator Guide SIP Release 2.0
