Hi shehzaad,
welcome to the forums.
Sure, you can "import" the ASCII config file from old 2500 series into the 3500/3600 series, except any configuration related to QoS, if exists.
None of my clients are using the "internal" DHCP server, but in some cases it'd make sense.
I tried to define an host declaration:
ena
conf t
ip dhcp-server pool test host 10.10.10.10 aa.bb.cc.dd.ee.ff option-1 255.255.255.0 option-3 10.10.10.1
Possible values are:
host Static IP allocation
lease Pool's lease time
option-1 Configure client's subnetmask
option-120 Configure list of SIP servers
option-150 Configure list of TFTP servers
option-176 Configure Avaya IP phones' option-176 parameters
option-241 Configure Avaya IP phones' option-241 parameters
option-242 Configure Avaya IP phones' option-242 parameters
option-3 Configure list of routers
option-6 Configure DNS servers
option-60 Vendor class identifier option
range Dynamic IP address allocation
Good luck