Installation and Operation Manual

Table Of Contents
TD 92579EN
10 April 2015 / Ver. N
Installation and Operation Manual
IP-DECT Base Station & IP-DECT Gateway (software version 7.2.X)
166
supplied by the DHCP server are ignored. This is especially useful if in a given setup, some
devices are to be configured differently but the majority is still configured by DHCP.
This can be achieved using the following config file options:
H.5 Known Problems with Lengthy Options
The minimum space available for options in a BOOTP/DHCP record is 312 byte. There are
some extension mechanisms but only a few DHCP servers support it. The Windows 2000
DHCP server for example does not, but silently truncates options not fitting in this 312
byte space.
H.6 Known Problems with VLAN Configurations
The handling of the 802.1q VLAN ID is a bit tricky. If not hard configured otherwise, the
device will request a DHCP lease using the Ethernet switch ports default VLAN ID (that is,
it will not send any VLAN header). It will thus receive a DHCP offer dedicated to devices on
that VLAN. If this offer includes a VLAN ID option, the device will not accept the offered
lease, set the VLAN ID to the value received in the otherwise disregarded offer and start
the DHCP process all over again. Now, the DHCP request will be issued on a new VLAN ID.
Therefore, the DHCP server will now send an offer dedicated for devices on that new
VLAN. This will most probably be a different DHCP scope.
As a consequence, DHCP options on a non-default VLAN must be configured twice. The
VLAN ID option itself must be configured in the default VLANs DHCP scope. All other
options must be configured in the new VLANs DHCP scope.
Be sure to configure the VLAN in both scopes identically. If not, the DHCP client process
will never terminate, since it will always detect a changed VLAN ID, set the VLAN ID and
restart the DHCP process.
Here is how DHCP leases are handled in detail:
First boot
The client will broadcast a DHCP DISCOVER, expecting an OFFER from the server including
all requested parameters. If the client intends to use the offered lease, it will issue a
request for the offered lease. Once it receives an ACK for the lease requested, it will
configure itself accordingly. All lease information is stored in the devices config file using
the /laddr option (unless suppressed using /no-keep).
Re-boot
If there is lease information (in the /laddr config file option), the client will broadcast
requests for the same lease again. If there is no answer within 30 seconds, the device will
configure itself using the parameters in /laddr. It will nevertheless continue to request this
lease from the DHCP server again (every 30 seconds, a broadcast will be sent).
config change UP1 /no-dhcp The update server uses the config files configuration
even though there is a configuration supplied from
DHCP (innovaphone vendor options "Update URL
[215]" and "Update Poll Interval [216]" are
ignored).
config change DHCPn /no-vlan The VLAN settings use the config files configuration
even though there is a configuration supplied from
DHCP (innovaphone vendor options "VLAN ID
[206]" and "VLAN Priority [207]" are ignored).
config change DHCPn /no-vendor All vendor options are ignored.