132 lines
4.3 KiB
Text
132 lines
4.3 KiB
Text
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Generic HDLC layer
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Krzysztof Halasa <khc@pm.waw.pl>
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January, 2003
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Generic HDLC layer currently supports:
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- Frame Relay (ANSI, CCITT and no LMI), with ARP support (no InARP).
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Normal (routed) and Ethernet-bridged (Ethernet device emulation)
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interfaces can share a single PVC.
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- raw HDLC - either IP (IPv4) interface or Ethernet device emulation.
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- Cisco HDLC,
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- PPP (uses syncppp.c),
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- X.25 (uses X.25 routines).
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There are hardware drivers for the following cards:
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- C101 by Moxa Technologies Co., Ltd.
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- RISCom/N2 by SDL Communications Inc.
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- and others, some not in the official kernel.
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Ethernet device emulation (using HDLC or Frame-Relay PVC) is compatible
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with IEEE 802.1Q (VLANs) and 802.1D (Ethernet bridging).
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Make sure the hdlc.o and the hardware driver are loaded. It should
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create a number of "hdlc" (hdlc0 etc) network devices, one for each
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WAN port. You'll need the "sethdlc" utility, get it from:
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http://hq.pm.waw.pl/hdlc/
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Compile sethdlc.c utility:
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gcc -O2 -Wall -o sethdlc sethdlc.c
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Make sure you're using a correct version of sethdlc for your kernel.
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Use sethdlc to set physical interface, clock rate, HDLC mode used,
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and add any required PVCs if using Frame Relay.
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Usually you want something like:
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sethdlc hdlc0 clock int rate 128000
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sethdlc hdlc0 cisco interval 10 timeout 25
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or
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sethdlc hdlc0 rs232 clock ext
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sethdlc hdlc0 fr lmi ansi
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sethdlc hdlc0 create 99
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ifconfig hdlc0 up
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ifconfig pvc0 localIP pointopoint remoteIP
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In Frame Relay mode, ifconfig master hdlc device up (without assigning
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any IP address to it) before using pvc devices.
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Setting interface:
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* v35 | rs232 | x21 | t1 | e1 - sets physical interface for a given port
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if the card has software-selectable interfaces
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loopback - activate hardware loopback (for testing only)
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* clock ext - external clock (uses DTE RX and TX clock)
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* clock int - internal clock (provides clock signal on DCE clock output)
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* clock txint - TX internal, RX external (provides TX clock on DCE output)
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* clock txfromrx - TX clock derived from RX clock (TX clock on DCE output)
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* rate - sets clock rate in bps (not required for external clock or
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for txfromrx)
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Setting protocol:
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* hdlc - sets raw HDLC (IP-only) mode
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nrz / nrzi / fm-mark / fm-space / manchester - sets transmission code
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no-parity / crc16 / crc16-pr0 (CRC16 with preset zeros) / crc32-itu
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crc16-itu (CRC16 with ITU-T polynomial) / crc16-itu-pr0 - sets parity
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* hdlc-eth - Ethernet device emulation using HDLC. Parity and encoding
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as above.
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* cisco - sets Cisco HDLC mode (IP, IPv6 and IPX supported)
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interval - time in seconds between keepalive packets
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timeout - time in seconds after last received keepalive packet before
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we assume the link is down
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* ppp - sets synchronous PPP mode
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* x25 - sets X.25 mode
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* fr - Frame Relay mode
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lmi ansi / ccitt / none - LMI (link management) type
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dce - Frame Relay DCE (network) side LMI instead of default DTE (user).
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It has nothing to do with clocks!
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t391 - link integrity verification polling timer (in seconds) - user
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t392 - polling verification timer (in seconds) - network
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n391 - full status polling counter - user
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n392 - error threshold - both user and network
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n393 - monitored events count - both user and network
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Frame-Relay only:
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* create n | delete n - adds / deletes PVC interface with DLCI #n.
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Newly created interface will be named pvc0, pvc1 etc.
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* create ether n | delete ether n - adds a device for Ethernet-bridged
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frames. The device will be named pvceth0, pvceth1 etc.
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Board-specific issues
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---------------------
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n2.o and c101.o need parameters to work:
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insmod n2 hw=io,irq,ram,ports[:io,irq,...]
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example:
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insmod n2 hw=0x300,10,0xD0000,01
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or
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insmod c101 hw=irq,ram[:irq,...]
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example:
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insmod c101 hw=9,0xdc000
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If built into the kernel, these drivers need kernel (command line) parameters:
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n2.hw=io,irq,ram,ports:...
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or
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c101.hw=irq,ram:...
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If you have a problem with N2 or C101 card, you can issue the "private"
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command to see port's packet descriptor rings (in kernel logs):
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sethdlc hdlc0 private
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The hardware driver has to be build with CONFIG_HDLC_DEBUG_RINGS.
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Attaching this info to bug reports would be helpful. Anyway, let me know
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if you have problems using this.
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For patches and other info look at http://hq.pm.waw.pl/hdlc/
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