generic-hdlc.rst (4498B)
1.. SPDX-License-Identifier: GPL-2.0 2 3================== 4Generic HDLC layer 5================== 6 7Krzysztof Halasa <khc@pm.waw.pl> 8 9 10Generic HDLC layer currently supports: 11 121. Frame Relay (ANSI, CCITT, Cisco and no LMI) 13 14 - Normal (routed) and Ethernet-bridged (Ethernet device emulation) 15 interfaces can share a single PVC. 16 - ARP support (no InARP support in the kernel - there is an 17 experimental InARP user-space daemon available on: 18 http://www.kernel.org/pub/linux/utils/net/hdlc/). 19 202. raw HDLC - either IP (IPv4) interface or Ethernet device emulation 213. Cisco HDLC 224. PPP 235. X.25 (uses X.25 routines). 24 25Generic HDLC is a protocol driver only - it needs a low-level driver 26for your particular hardware. 27 28Ethernet device emulation (using HDLC or Frame-Relay PVC) is compatible 29with IEEE 802.1Q (VLANs) and 802.1D (Ethernet bridging). 30 31 32Make sure the hdlc.o and the hardware driver are loaded. It should 33create a number of "hdlc" (hdlc0 etc) network devices, one for each 34WAN port. You'll need the "sethdlc" utility, get it from: 35 36 http://www.kernel.org/pub/linux/utils/net/hdlc/ 37 38Compile sethdlc.c utility:: 39 40 gcc -O2 -Wall -o sethdlc sethdlc.c 41 42Make sure you're using a correct version of sethdlc for your kernel. 43 44Use sethdlc to set physical interface, clock rate, HDLC mode used, 45and add any required PVCs if using Frame Relay. 46Usually you want something like:: 47 48 sethdlc hdlc0 clock int rate 128000 49 sethdlc hdlc0 cisco interval 10 timeout 25 50 51or:: 52 53 sethdlc hdlc0 rs232 clock ext 54 sethdlc hdlc0 fr lmi ansi 55 sethdlc hdlc0 create 99 56 ifconfig hdlc0 up 57 ifconfig pvc0 localIP pointopoint remoteIP 58 59In Frame Relay mode, ifconfig master hdlc device up (without assigning 60any IP address to it) before using pvc devices. 61 62 63Setting interface: 64 65* v35 | rs232 | x21 | t1 | e1 66 - sets physical interface for a given port 67 if the card has software-selectable interfaces 68 loopback 69 - activate hardware loopback (for testing only) 70* clock ext 71 - both RX clock and TX clock external 72* clock int 73 - both RX clock and TX clock internal 74* clock txint 75 - RX clock external, TX clock internal 76* clock txfromrx 77 - RX clock external, TX clock derived from RX clock 78* rate 79 - sets clock rate in bps (for "int" or "txint" clock only) 80 81 82Setting protocol: 83 84* hdlc - sets raw HDLC (IP-only) mode 85 86 nrz / nrzi / fm-mark / fm-space / manchester - sets transmission code 87 88 no-parity / crc16 / crc16-pr0 (CRC16 with preset zeros) / crc32-itu 89 90 crc16-itu (CRC16 with ITU-T polynomial) / crc16-itu-pr0 - sets parity 91 92* hdlc-eth - Ethernet device emulation using HDLC. Parity and encoding 93 as above. 94 95* cisco - sets Cisco HDLC mode (IP, IPv6 and IPX supported) 96 97 interval - time in seconds between keepalive packets 98 99 timeout - time in seconds after last received keepalive packet before 100 we assume the link is down 101 102* ppp - sets synchronous PPP mode 103 104* x25 - sets X.25 mode 105 106* fr - Frame Relay mode 107 108 lmi ansi / ccitt / cisco / none - LMI (link management) type 109 110 dce - Frame Relay DCE (network) side LMI instead of default DTE (user). 111 112 It has nothing to do with clocks! 113 114 - t391 - link integrity verification polling timer (in seconds) - user 115 - t392 - polling verification timer (in seconds) - network 116 - n391 - full status polling counter - user 117 - n392 - error threshold - both user and network 118 - n393 - monitored events count - both user and network 119 120Frame-Relay only: 121 122* create n | delete n - adds / deletes PVC interface with DLCI #n. 123 Newly created interface will be named pvc0, pvc1 etc. 124 125* create ether n | delete ether n - adds a device for Ethernet-bridged 126 frames. The device will be named pvceth0, pvceth1 etc. 127 128 129 130 131Board-specific issues 132--------------------- 133 134n2.o and c101.o need parameters to work:: 135 136 insmod n2 hw=io,irq,ram,ports[:io,irq,...] 137 138example:: 139 140 insmod n2 hw=0x300,10,0xD0000,01 141 142or:: 143 144 insmod c101 hw=irq,ram[:irq,...] 145 146example:: 147 148 insmod c101 hw=9,0xdc000 149 150If built into the kernel, these drivers need kernel (command line) parameters:: 151 152 n2.hw=io,irq,ram,ports:... 153 154or:: 155 156 c101.hw=irq,ram:... 157 158 159 160If you have a problem with N2, C101 or PLX200SYN card, you can issue the 161"private" command to see port's packet descriptor rings (in kernel logs):: 162 163 sethdlc hdlc0 private 164 165The hardware driver has to be build with #define DEBUG_RINGS. 166Attaching this info to bug reports would be helpful. Anyway, let me know 167if you have problems using this. 168 169For patches and other info look at: 170<http://www.kernel.org/pub/linux/utils/net/hdlc/>.