Using sethdlc utility to configure Tahoe cards under FreeBSD
Sethdlc utility is used to configure Tahoe cards. Its main function is to select the protocol used on the WAN link:
Cisco®HDLC: sethdlc th0 cisco
Synchroniczne PPP: sethdlc th0 ppp
Frame Relay: sethdlc th0 fr [lmi type [parameter]]
where:
type is LMI ytpe: ansi, ccitt, cisco
parameter is a Frame Relay parameter: t391 value, n391 value, n392 value
Moreover in case of Frame Relay protocol you can create and delete PVCs (Permanent Virtual Circuits) with given DLCI values:
sethdlc th0 create 99
sethdlc th0 delete 99
After creating a PVC, a new 'pvc' interface is created with name derived from DLCI value - e.g. pvc99 in above example.
In case of Tahoe 971/972 cards you also have to specify, which timeslots are used for transmission. Timeslots can be given in two ways - as a list of numbers (from 1 to 32) and ranges separated by commas or as a string of zeros and ones (where '0' means an unused slot and '1' - an used one, with the first slot at the beginning of the string):
Use of the first timeslot automaticaly enables unframed mode, where whole 2048 kbps are used for data transfer. Otherwise the first timeslot is used for framing synchronization.
The command below enables and disables, respectively, transmission of the CRC4 checksum:
sethdlc th0 crc4 on
sethdlc th0 crc4 off
Another command switches betweed short haul (50m range) and long haul (2000m range) mode:
sethdlc th0 short
sethdlc th0 long
After configuring a card using the sethdlc utility you can proceed to regular interface configuration (using th0, th1 or pvc## interfaces), routing setup, etc.
