performance with 20000 classes; release a lease manually

Frank Bulk frnkblk at
Thu May 28 03:43:46 UTC 2009

Don't forget that the cable modem will store in its bridge table all the MAC
addresses of the attached devices, and according to CableLabs standards,
that table does not age.  So if you set the MaxCPE=1 for a cable modem
configuration file and attach a device, and a customer later wants to
attached a different CPE to the cable modem, the only way to clear out the
bridge table is to reset the cable modem.


-----Original Message-----
From: dhcp-users-bounces at
[mailto:dhcp-users-bounces at] On Behalf Of stefan novak
Sent: Wednesday, May 27, 2009 11:00 AM
To: dhcp-users at
Subject: performance with 20000 classes; release a lease manually


My config is very simple and works as expected.
The client behind the cable modem always gets the fixed address. is
this config scaleable to 20000 classes, or is there another way to
configure such a scenario.

My secound question is about the file. is it possible to
release an already taken lease?
that if the client behind the cable modem changes, the ip is assigned
to the new client. is that possible? setting the lease time to 5min.
seams not the solution for many many clients.....

class "customer1" {
         match if binary-to-ascii(16, 8, ":",  option agent.remote-id
) = "0:1e:69:ef:8e:b5"; # <- Modem Mac
         lease limit 1;

shared-network test{

subnet netmask {
        option routers;
        option broadcast-address;
        option time-servers;

  host testmodem1 { hardware ethernet 00:1e:69:ef:8e:b5; fixed-address; filename "test1.cfg";}

subnet xx.62.31.0 netmask {
        option routers xx.62.31.1;
        option broadcast-address xx.62.31.255;

        pool {
                allow members of "customer1";
                range xx.62.31.15 xx.62.31.15;
        pool {
                deny members of "customer1";
                range xx.62.31.2 xx.62.31.10;

thx Stefan
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