0001 .. SPDX-License-Identifier: GPL-2.0
0002
0003 ==================
0004 Generic HDLC layer
0005 ==================
0006
0007 Krzysztof Halasa <khc@pm.waw.pl>
0008
0009
0010 Generic HDLC layer currently supports:
0011
0012 1. Frame Relay (ANSI, CCITT, Cisco and no LMI)
0013
0014 - Normal (routed) and Ethernet-bridged (Ethernet device emulation)
0015 interfaces can share a single PVC.
0016 - ARP support (no InARP support in the kernel - there is an
0017 experimental InARP user-space daemon available on:
0018 http://www.kernel.org/pub/linux/utils/net/hdlc/).
0019
0020 2. raw HDLC - either IP (IPv4) interface or Ethernet device emulation
0021 3. Cisco HDLC
0022 4. PPP
0023 5. X.25 (uses X.25 routines).
0024
0025 Generic HDLC is a protocol driver only - it needs a low-level driver
0026 for your particular hardware.
0027
0028 Ethernet device emulation (using HDLC or Frame-Relay PVC) is compatible
0029 with IEEE 802.1Q (VLANs) and 802.1D (Ethernet bridging).
0030
0031
0032 Make sure the hdlc.o and the hardware driver are loaded. It should
0033 create a number of "hdlc" (hdlc0 etc) network devices, one for each
0034 WAN port. You'll need the "sethdlc" utility, get it from:
0035
0036 http://www.kernel.org/pub/linux/utils/net/hdlc/
0037
0038 Compile sethdlc.c utility::
0039
0040 gcc -O2 -Wall -o sethdlc sethdlc.c
0041
0042 Make sure you're using a correct version of sethdlc for your kernel.
0043
0044 Use sethdlc to set physical interface, clock rate, HDLC mode used,
0045 and add any required PVCs if using Frame Relay.
0046 Usually you want something like::
0047
0048 sethdlc hdlc0 clock int rate 128000
0049 sethdlc hdlc0 cisco interval 10 timeout 25
0050
0051 or::
0052
0053 sethdlc hdlc0 rs232 clock ext
0054 sethdlc hdlc0 fr lmi ansi
0055 sethdlc hdlc0 create 99
0056 ifconfig hdlc0 up
0057 ifconfig pvc0 localIP pointopoint remoteIP
0058
0059 In Frame Relay mode, ifconfig master hdlc device up (without assigning
0060 any IP address to it) before using pvc devices.
0061
0062
0063 Setting interface:
0064
0065 * v35 | rs232 | x21 | t1 | e1
0066 - sets physical interface for a given port
0067 if the card has software-selectable interfaces
0068 loopback
0069 - activate hardware loopback (for testing only)
0070 * clock ext
0071 - both RX clock and TX clock external
0072 * clock int
0073 - both RX clock and TX clock internal
0074 * clock txint
0075 - RX clock external, TX clock internal
0076 * clock txfromrx
0077 - RX clock external, TX clock derived from RX clock
0078 * rate
0079 - sets clock rate in bps (for "int" or "txint" clock only)
0080
0081
0082 Setting protocol:
0083
0084 * hdlc - sets raw HDLC (IP-only) mode
0085
0086 nrz / nrzi / fm-mark / fm-space / manchester - sets transmission code
0087
0088 no-parity / crc16 / crc16-pr0 (CRC16 with preset zeros) / crc32-itu
0089
0090 crc16-itu (CRC16 with ITU-T polynomial) / crc16-itu-pr0 - sets parity
0091
0092 * hdlc-eth - Ethernet device emulation using HDLC. Parity and encoding
0093 as above.
0094
0095 * cisco - sets Cisco HDLC mode (IP, IPv6 and IPX supported)
0096
0097 interval - time in seconds between keepalive packets
0098
0099 timeout - time in seconds after last received keepalive packet before
0100 we assume the link is down
0101
0102 * ppp - sets synchronous PPP mode
0103
0104 * x25 - sets X.25 mode
0105
0106 * fr - Frame Relay mode
0107
0108 lmi ansi / ccitt / cisco / none - LMI (link management) type
0109
0110 dce - Frame Relay DCE (network) side LMI instead of default DTE (user).
0111
0112 It has nothing to do with clocks!
0113
0114 - t391 - link integrity verification polling timer (in seconds) - user
0115 - t392 - polling verification timer (in seconds) - network
0116 - n391 - full status polling counter - user
0117 - n392 - error threshold - both user and network
0118 - n393 - monitored events count - both user and network
0119
0120 Frame-Relay only:
0121
0122 * create n | delete n - adds / deletes PVC interface with DLCI #n.
0123 Newly created interface will be named pvc0, pvc1 etc.
0124
0125 * create ether n | delete ether n - adds a device for Ethernet-bridged
0126 frames. The device will be named pvceth0, pvceth1 etc.
0127
0128
0129
0130
0131 Board-specific issues
0132 ---------------------
0133
0134 n2.o and c101.o need parameters to work::
0135
0136 insmod n2 hw=io,irq,ram,ports[:io,irq,...]
0137
0138 example::
0139
0140 insmod n2 hw=0x300,10,0xD0000,01
0141
0142 or::
0143
0144 insmod c101 hw=irq,ram[:irq,...]
0145
0146 example::
0147
0148 insmod c101 hw=9,0xdc000
0149
0150 If built into the kernel, these drivers need kernel (command line) parameters::
0151
0152 n2.hw=io,irq,ram,ports:...
0153
0154 or::
0155
0156 c101.hw=irq,ram:...
0157
0158
0159
0160 If you have a problem with N2, C101 or PLX200SYN card, you can issue the
0161 "private" command to see port's packet descriptor rings (in kernel logs)::
0162
0163 sethdlc hdlc0 private
0164
0165 The hardware driver has to be build with #define DEBUG_RINGS.
0166 Attaching this info to bug reports would be helpful. Anyway, let me know
0167 if you have problems using this.
0168
0169 For patches and other info look at:
0170 <http://www.kernel.org/pub/linux/utils/net/hdlc/>.
