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Documentation / networking / generic-hdlc.txt




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Based on kernel version 3.9. Page generated on 2013-05-02 23:11 EST.

1	Generic HDLC layer
2	Krzysztof Halasa <khc@pm.waw.pl>
3	
4	
5	Generic HDLC layer currently supports:
6	1. Frame Relay (ANSI, CCITT, Cisco and no LMI)
7	   - Normal (routed) and Ethernet-bridged (Ethernet device emulation)
8	     interfaces can share a single PVC.
9	   - ARP support (no InARP support in the kernel - there is an
10	     experimental InARP user-space daemon available on:
11	     http://www.kernel.org/pub/linux/utils/net/hdlc/).
12	2. raw HDLC - either IP (IPv4) interface or Ethernet device emulation
13	3. Cisco HDLC
14	4. PPP
15	5. X.25 (uses X.25 routines).
16	
17	Generic HDLC is a protocol driver only - it needs a low-level driver
18	for your particular hardware.
19	
20	Ethernet device emulation (using HDLC or Frame-Relay PVC) is compatible
21	with IEEE 802.1Q (VLANs) and 802.1D (Ethernet bridging).
22	
23	
24	Make sure the hdlc.o and the hardware driver are loaded. It should
25	create a number of "hdlc" (hdlc0 etc) network devices, one for each
26	WAN port. You'll need the "sethdlc" utility, get it from:
27		http://www.kernel.org/pub/linux/utils/net/hdlc/
28	
29	Compile sethdlc.c utility:
30		gcc -O2 -Wall -o sethdlc sethdlc.c
31	Make sure you're using a correct version of sethdlc for your kernel.
32	
33	Use sethdlc to set physical interface, clock rate, HDLC mode used,
34	and add any required PVCs if using Frame Relay.
35	Usually you want something like:
36	
37		sethdlc hdlc0 clock int rate 128000
38		sethdlc hdlc0 cisco interval 10 timeout 25
39	or
40		sethdlc hdlc0 rs232 clock ext
41		sethdlc hdlc0 fr lmi ansi
42		sethdlc hdlc0 create 99
43		ifconfig hdlc0 up
44		ifconfig pvc0 localIP pointopoint remoteIP
45	
46	In Frame Relay mode, ifconfig master hdlc device up (without assigning
47	any IP address to it) before using pvc devices.
48	
49	
50	Setting interface:
51	
52	* v35 | rs232 | x21 | t1 | e1 - sets physical interface for a given port
53	                                if the card has software-selectable interfaces
54	  loopback - activate hardware loopback (for testing only)
55	* clock ext - both RX clock and TX clock external
56	* clock int - both RX clock and TX clock internal
57	* clock txint - RX clock external, TX clock internal
58	* clock txfromrx - RX clock external, TX clock derived from RX clock
59	* rate - sets clock rate in bps (for "int" or "txint" clock only)
60	
61	
62	Setting protocol:
63	
64	* hdlc - sets raw HDLC (IP-only) mode
65	  nrz / nrzi / fm-mark / fm-space / manchester - sets transmission code
66	  no-parity / crc16 / crc16-pr0 (CRC16 with preset zeros) / crc32-itu
67	  crc16-itu (CRC16 with ITU-T polynomial) / crc16-itu-pr0 - sets parity
68	
69	* hdlc-eth - Ethernet device emulation using HDLC. Parity and encoding
70	  as above.
71	
72	* cisco - sets Cisco HDLC mode (IP, IPv6 and IPX supported)
73	  interval - time in seconds between keepalive packets
74	  timeout - time in seconds after last received keepalive packet before
75	            we assume the link is down
76	
77	* ppp - sets synchronous PPP mode
78	
79	* x25 - sets X.25 mode
80	
81	* fr - Frame Relay mode
82	  lmi ansi / ccitt / cisco / none - LMI (link management) type
83	  dce - Frame Relay DCE (network) side LMI instead of default DTE (user).
84	  It has nothing to do with clocks!
85	  t391 - link integrity verification polling timer (in seconds) - user
86	  t392 - polling verification timer (in seconds) - network
87	  n391 - full status polling counter - user
88	  n392 - error threshold - both user and network
89	  n393 - monitored events count - both user and network
90	
91	Frame-Relay only:
92	* create n | delete n - adds / deletes PVC interface with DLCI #n.
93	  Newly created interface will be named pvc0, pvc1 etc.
94	
95	* create ether n | delete ether n - adds a device for Ethernet-bridged
96	  frames. The device will be named pvceth0, pvceth1 etc.
97	
98	
99	
100	
101	Board-specific issues
102	---------------------
103	
104	n2.o and c101.o need parameters to work:
105	
106		insmod n2 hw=io,irq,ram,ports[:io,irq,...]
107	example:
108		insmod n2 hw=0x300,10,0xD0000,01
109	
110	or
111		insmod c101 hw=irq,ram[:irq,...]
112	example:
113		insmod c101 hw=9,0xdc000
114	
115	If built into the kernel, these drivers need kernel (command line) parameters:
116		n2.hw=io,irq,ram,ports:...
117	or
118		c101.hw=irq,ram:...
119	
120	
121	
122	If you have a problem with N2, C101 or PLX200SYN card, you can issue the
123	"private" command to see port's packet descriptor rings (in kernel logs):
124	
125		sethdlc hdlc0 private
126	
127	The hardware driver has to be build with #define DEBUG_RINGS.
128	Attaching this info to bug reports would be helpful. Anyway, let me know
129	if you have problems using this.
130	
131	For patches and other info look at:
132	<http://www.kernel.org/pub/linux/utils/net/hdlc/>.
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