Using Option 82 for static ip assignment

[Eric Helm]

Hello,
We have a FTTP deployment where the fiber switch adds the
agent.circuit-id information to the DHCP packets. I am using this
information to assign a static IP for each subscriber.
When the subscriber equipment is changed, I see a log message that says
'no free leases' and the device does not get an IP assigned. Once the
lease for the old equipment expires, everything is good to go.

In this scenario, is my only course of action to reduce the lease times?

Here is part of my config:

authoritative;
lease-file-name "/etc/dhcp/dhcpd.leases";
pid-file-name "/var/run/dhcp/dhcpd.pid";
log-facility local1;
option domain-name "ruraltel.net";
option domain-name-servers 24.225.0.1, 24.225.5.2;
option classless-routes code 121 = array of unsigned integer 8;
default-lease-time 1800;
max-lease-time 43200;
option time-offset -21600;
option ip-forwarding off;
ping-check on;

class "Occam_Lab_ONT"
{
        match if option agent.circuit-id = "occam-9/Ethernet1:vlan2";
}

subnet 192.168.121.0 netmask 255.255.255.128 #Occam FTTH Lab
{
        pool
        {
                allow members of "Occam_Lab_ONT";
                range 192.168.121.5;
                failover peer "failover";
                deny dynamic bootp clients;
        }
        option routers 192.168.121.1;
        option broadcast-address 192.168.121.127;
        option tftp-server-name "24.225.0.131";
        filename "OccamONT2342.cfg";
        next-server 24.225.0.131;

Thanks,
Eric