diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /Documentation/networking/eql.txt |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
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1 | EQL Driver: Serial IP Load Balancing HOWTO | ||
2 | Simon "Guru Aleph-Null" Janes, simon@ncm.com | ||
3 | v1.1, February 27, 1995 | ||
4 | |||
5 | This is the manual for the EQL device driver. EQL is a software device | ||
6 | that lets you load-balance IP serial links (SLIP or uncompressed PPP) | ||
7 | to increase your bandwidth. It will not reduce your latency (i.e. ping | ||
8 | times) except in the case where you already have lots of traffic on | ||
9 | your link, in which it will help them out. This driver has been tested | ||
10 | with the 1.1.75 kernel, and is known to have patched cleanly with | ||
11 | 1.1.86. Some testing with 1.1.92 has been done with the v1.1 patch | ||
12 | which was only created to patch cleanly in the very latest kernel | ||
13 | source trees. (Yes, it worked fine.) | ||
14 | |||
15 | 1. Introduction | ||
16 | |||
17 | Which is worse? A huge fee for a 56K leased line or two phone lines? | ||
18 | It's probably the former. If you find yourself craving more bandwidth, | ||
19 | and have a ISP that is flexible, it is now possible to bind modems | ||
20 | together to work as one point-to-point link to increase your | ||
21 | bandwidth. All without having to have a special black box on either | ||
22 | side. | ||
23 | |||
24 | |||
25 | The eql driver has only been tested with the Livingston PortMaster-2e | ||
26 | terminal server. I do not know if other terminal servers support load- | ||
27 | balancing, but I do know that the PortMaster does it, and does it | ||
28 | almost as well as the eql driver seems to do it (-- Unfortunately, in | ||
29 | my testing so far, the Livingston PortMaster 2e's load-balancing is a | ||
30 | good 1 to 2 KB/s slower than the test machine working with a 28.8 Kbps | ||
31 | and 14.4 Kbps connection. However, I am not sure that it really is | ||
32 | the PortMaster, or if it's Linux's TCP drivers. I'm told that Linux's | ||
33 | TCP implementation is pretty fast though.--) | ||
34 | |||
35 | |||
36 | I suggest to ISPs out there that it would probably be fair to charge | ||
37 | a load-balancing client 75% of the cost of the second line and 50% of | ||
38 | the cost of the third line etc... | ||
39 | |||
40 | |||
41 | Hey, we can all dream you know... | ||
42 | |||
43 | |||
44 | 2. Kernel Configuration | ||
45 | |||
46 | Here I describe the general steps of getting a kernel up and working | ||
47 | with the eql driver. From patching, building, to installing. | ||
48 | |||
49 | |||
50 | 2.1. Patching The Kernel | ||
51 | |||
52 | If you do not have or cannot get a copy of the kernel with the eql | ||
53 | driver folded into it, get your copy of the driver from | ||
54 | ftp://slaughter.ncm.com/pub/Linux/LOAD_BALANCING/eql-1.1.tar.gz. | ||
55 | Unpack this archive someplace obvious like /usr/local/src/. It will | ||
56 | create the following files: | ||
57 | |||
58 | |||
59 | |||
60 | ______________________________________________________________________ | ||
61 | -rw-r--r-- guru/ncm 198 Jan 19 18:53 1995 eql-1.1/NO-WARRANTY | ||
62 | -rw-r--r-- guru/ncm 30620 Feb 27 21:40 1995 eql-1.1/eql-1.1.patch | ||
63 | -rwxr-xr-x guru/ncm 16111 Jan 12 22:29 1995 eql-1.1/eql_enslave | ||
64 | -rw-r--r-- guru/ncm 2195 Jan 10 21:48 1995 eql-1.1/eql_enslave.c | ||
65 | ______________________________________________________________________ | ||
66 | |||
67 | Unpack a recent kernel (something after 1.1.92) someplace convenient | ||
68 | like say /usr/src/linux-1.1.92.eql. Use symbolic links to point | ||
69 | /usr/src/linux to this development directory. | ||
70 | |||
71 | |||
72 | Apply the patch by running the commands: | ||
73 | |||
74 | |||
75 | ______________________________________________________________________ | ||
76 | cd /usr/src | ||
77 | patch </usr/local/src/eql-1.1/eql-1.1.patch | ||
78 | ______________________________________________________________________ | ||
79 | |||
80 | |||
81 | |||
82 | |||
83 | |||
84 | 2.2. Building The Kernel | ||
85 | |||
86 | After patching the kernel, run make config and configure the kernel | ||
87 | for your hardware. | ||
88 | |||
89 | |||
90 | After configuration, make and install according to your habit. | ||
91 | |||
92 | |||
93 | 3. Network Configuration | ||
94 | |||
95 | So far, I have only used the eql device with the DSLIP SLIP connection | ||
96 | manager by Matt Dillon (-- "The man who sold his soul to code so much | ||
97 | so quickly."--) . How you configure it for other "connection" | ||
98 | managers is up to you. Most other connection managers that I've seen | ||
99 | don't do a very good job when it comes to handling more than one | ||
100 | connection. | ||
101 | |||
102 | |||
103 | 3.1. /etc/rc.d/rc.inet1 | ||
104 | |||
105 | In rc.inet1, ifconfig the eql device to the IP address you usually use | ||
106 | for your machine, and the MTU you prefer for your SLIP lines. One | ||
107 | could argue that MTU should be roughly half the usual size for two | ||
108 | modems, one-third for three, one-fourth for four, etc... But going | ||
109 | too far below 296 is probably overkill. Here is an example ifconfig | ||
110 | command that sets up the eql device: | ||
111 | |||
112 | |||
113 | |||
114 | ______________________________________________________________________ | ||
115 | ifconfig eql 198.67.33.239 mtu 1006 | ||
116 | ______________________________________________________________________ | ||
117 | |||
118 | |||
119 | |||
120 | |||
121 | |||
122 | Once the eql device is up and running, add a static default route to | ||
123 | it in the routing table using the cool new route syntax that makes | ||
124 | life so much easier: | ||
125 | |||
126 | |||
127 | |||
128 | ______________________________________________________________________ | ||
129 | route add default eql | ||
130 | ______________________________________________________________________ | ||
131 | |||
132 | |||
133 | 3.2. Enslaving Devices By Hand | ||
134 | |||
135 | Enslaving devices by hand requires two utility programs: eql_enslave | ||
136 | and eql_emancipate (-- eql_emancipate hasn't been written because when | ||
137 | an enslaved device "dies", it is automatically taken out of the queue. | ||
138 | I haven't found a good reason to write it yet... other than for | ||
139 | completeness, but that isn't a good motivator is it?--) | ||
140 | |||
141 | |||
142 | The syntax for enslaving a device is "eql_enslave <master-name> | ||
143 | <slave-name> <estimated-bps>". Here are some example enslavings: | ||
144 | |||
145 | |||
146 | |||
147 | ______________________________________________________________________ | ||
148 | eql_enslave eql sl0 28800 | ||
149 | eql_enslave eql ppp0 14400 | ||
150 | eql_enslave eql sl1 57600 | ||
151 | ______________________________________________________________________ | ||
152 | |||
153 | |||
154 | |||
155 | |||
156 | |||
157 | When you want to free a device from its life of slavery, you can | ||
158 | either down the device with ifconfig (eql will automatically bury the | ||
159 | dead slave and remove it from its queue) or use eql_emancipate to free | ||
160 | it. (-- Or just ifconfig it down, and the eql driver will take it out | ||
161 | for you.--) | ||
162 | |||
163 | |||
164 | |||
165 | ______________________________________________________________________ | ||
166 | eql_emancipate eql sl0 | ||
167 | eql_emancipate eql ppp0 | ||
168 | eql_emancipate eql sl1 | ||
169 | ______________________________________________________________________ | ||
170 | |||
171 | |||
172 | |||
173 | |||
174 | |||
175 | 3.3. DSLIP Configuration for the eql Device | ||
176 | |||
177 | The general idea is to bring up and keep up as many SLIP connections | ||
178 | as you need, automatically. | ||
179 | |||
180 | |||
181 | 3.3.1. /etc/slip/runslip.conf | ||
182 | |||
183 | Here is an example runslip.conf: | ||
184 | |||
185 | |||
186 | |||
187 | |||
188 | |||
189 | |||
190 | |||
191 | |||
192 | |||
193 | |||
194 | |||
195 | |||
196 | |||
197 | |||
198 | |||
199 | ______________________________________________________________________ | ||
200 | name sl-line-1 | ||
201 | enabled | ||
202 | baud 38400 | ||
203 | mtu 576 | ||
204 | ducmd -e /etc/slip/dialout/cua2-288.xp -t 9 | ||
205 | command eql_enslave eql $interface 28800 | ||
206 | address 198.67.33.239 | ||
207 | line /dev/cua2 | ||
208 | |||
209 | name sl-line-2 | ||
210 | enabled | ||
211 | baud 38400 | ||
212 | mtu 576 | ||
213 | ducmd -e /etc/slip/dialout/cua3-288.xp -t 9 | ||
214 | command eql_enslave eql $interface 28800 | ||
215 | address 198.67.33.239 | ||
216 | line /dev/cua3 | ||
217 | ______________________________________________________________________ | ||
218 | |||
219 | |||
220 | |||
221 | |||
222 | |||
223 | 3.4. Using PPP and the eql Device | ||
224 | |||
225 | I have not yet done any load-balancing testing for PPP devices, mainly | ||
226 | because I don't have a PPP-connection manager like SLIP has with | ||
227 | DSLIP. I did find a good tip from LinuxNET:Billy for PPP performance: | ||
228 | make sure you have asyncmap set to something so that control | ||
229 | characters are not escaped. | ||
230 | |||
231 | |||
232 | I tried to fix up a PPP script/system for redialing lost PPP | ||
233 | connections for use with the eql driver the weekend of Feb 25-26 '95 | ||
234 | (Hereafter known as the 8-hour PPP Hate Festival). Perhaps later this | ||
235 | year. | ||
236 | |||
237 | |||
238 | 4. About the Slave Scheduler Algorithm | ||
239 | |||
240 | The slave scheduler probably could be replaced with a dozen other | ||
241 | things and push traffic much faster. The formula in the current set | ||
242 | up of the driver was tuned to handle slaves with wildly different | ||
243 | bits-per-second "priorities". | ||
244 | |||
245 | |||
246 | All testing I have done was with two 28.8 V.FC modems, one connecting | ||
247 | at 28800 bps or slower, and the other connecting at 14400 bps all the | ||
248 | time. | ||
249 | |||
250 | |||
251 | One version of the scheduler was able to push 5.3 K/s through the | ||
252 | 28800 and 14400 connections, but when the priorities on the links were | ||
253 | very wide apart (57600 vs. 14400) the "faster" modem received all | ||
254 | traffic and the "slower" modem starved. | ||
255 | |||
256 | |||
257 | 5. Testers' Reports | ||
258 | |||
259 | Some people have experimented with the eql device with newer | ||
260 | kernels (than 1.1.75). I have since updated the driver to patch | ||
261 | cleanly in newer kernels because of the removal of the old "slave- | ||
262 | balancing" driver config option. | ||
263 | |||
264 | |||
265 | o icee from LinuxNET patched 1.1.86 without any rejects and was able | ||
266 | to boot the kernel and enslave a couple of ISDN PPP links. | ||
267 | |||
268 | 5.1. Randolph Bentson's Test Report | ||
269 | |||
270 | |||
271 | |||
272 | |||
273 | |||
274 | |||
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328 | |||
329 | |||
330 | |||
331 | From bentson@grieg.seaslug.org Wed Feb 8 19:08:09 1995 | ||
332 | Date: Tue, 7 Feb 95 22:57 PST | ||
333 | From: Randolph Bentson <bentson@grieg.seaslug.org> | ||
334 | To: guru@ncm.com | ||
335 | Subject: EQL driver tests | ||
336 | |||
337 | |||
338 | I have been checking out your eql driver. (Nice work, that!) | ||
339 | Although you may already done this performance testing, here | ||
340 | are some data I've discovered. | ||
341 | |||
342 | Randolph Bentson | ||
343 | bentson@grieg.seaslug.org | ||
344 | |||
345 | --------------------------------------------------------- | ||
346 | |||
347 | |||
348 | A pseudo-device driver, EQL, written by Simon Janes, can be used | ||
349 | to bundle multiple SLIP connections into what appears to be a | ||
350 | single connection. This allows one to improve dial-up network | ||
351 | connectivity gradually, without having to buy expensive DSU/CSU | ||
352 | hardware and services. | ||
353 | |||
354 | I have done some testing of this software, with two goals in | ||
355 | mind: first, to ensure it actually works as described and | ||
356 | second, as a method of exercising my device driver. | ||
357 | |||
358 | The following performance measurements were derived from a set | ||
359 | of SLIP connections run between two Linux systems (1.1.84) using | ||
360 | a 486DX2/66 with a Cyclom-8Ys and a 486SLC/40 with a Cyclom-16Y. | ||
361 | (Ports 0,1,2,3 were used. A later configuration will distribute | ||
362 | port selection across the different Cirrus chips on the boards.) | ||
363 | Once a link was established, I timed a binary ftp transfer of | ||
364 | 289284 bytes of data. If there were no overhead (packet headers, | ||
365 | inter-character and inter-packet delays, etc.) the transfers | ||
366 | would take the following times: | ||
367 | |||
368 | bits/sec seconds | ||
369 | 345600 8.3 | ||
370 | 234600 12.3 | ||
371 | 172800 16.7 | ||
372 | 153600 18.8 | ||
373 | 76800 37.6 | ||
374 | 57600 50.2 | ||
375 | 38400 75.3 | ||
376 | 28800 100.4 | ||
377 | 19200 150.6 | ||
378 | 9600 301.3 | ||
379 | |||
380 | A single line running at the lower speeds and with large packets | ||
381 | comes to within 2% of this. Performance is limited for the higher | ||
382 | speeds (as predicted by the Cirrus databook) to an aggregate of | ||
383 | about 160 kbits/sec. The next round of testing will distribute | ||
384 | the load across two or more Cirrus chips. | ||
385 | |||
386 | The good news is that one gets nearly the full advantage of the | ||
387 | second, third, and fourth line's bandwidth. (The bad news is | ||
388 | that the connection establishment seemed fragile for the higher | ||
389 | speeds. Once established, the connection seemed robust enough.) | ||
390 | |||
391 | #lines speed mtu seconds theory actual %of | ||
392 | kbit/sec duration speed speed max | ||
393 | 3 115200 900 _ 345600 | ||
394 | 3 115200 400 18.1 345600 159825 46 | ||
395 | 2 115200 900 _ 230400 | ||
396 | 2 115200 600 18.1 230400 159825 69 | ||
397 | 2 115200 400 19.3 230400 149888 65 | ||
398 | 4 57600 900 _ 234600 | ||
399 | 4 57600 600 _ 234600 | ||
400 | 4 57600 400 _ 234600 | ||
401 | 3 57600 600 20.9 172800 138413 80 | ||
402 | 3 57600 900 21.2 172800 136455 78 | ||
403 | 3 115200 600 21.7 345600 133311 38 | ||
404 | 3 57600 400 22.5 172800 128571 74 | ||
405 | 4 38400 900 25.2 153600 114795 74 | ||
406 | 4 38400 600 26.4 153600 109577 71 | ||
407 | 4 38400 400 27.3 153600 105965 68 | ||
408 | 2 57600 900 29.1 115200 99410.3 86 | ||
409 | 1 115200 900 30.7 115200 94229.3 81 | ||
410 | 2 57600 600 30.2 115200 95789.4 83 | ||
411 | 3 38400 900 30.3 115200 95473.3 82 | ||
412 | 3 38400 600 31.2 115200 92719.2 80 | ||
413 | 1 115200 600 31.3 115200 92423 80 | ||
414 | 2 57600 400 32.3 115200 89561.6 77 | ||
415 | 1 115200 400 32.8 115200 88196.3 76 | ||
416 | 3 38400 400 33.5 115200 86353.4 74 | ||
417 | 2 38400 900 43.7 76800 66197.7 86 | ||
418 | 2 38400 600 44 76800 65746.4 85 | ||
419 | 2 38400 400 47.2 76800 61289 79 | ||
420 | 4 19200 900 50.8 76800 56945.7 74 | ||
421 | 4 19200 400 53.2 76800 54376.7 70 | ||
422 | 4 19200 600 53.7 76800 53870.4 70 | ||
423 | 1 57600 900 54.6 57600 52982.4 91 | ||
424 | 1 57600 600 56.2 57600 51474 89 | ||
425 | 3 19200 900 60.5 57600 47815.5 83 | ||
426 | 1 57600 400 60.2 57600 48053.8 83 | ||
427 | 3 19200 600 62 57600 46658.7 81 | ||
428 | 3 19200 400 64.7 57600 44711.6 77 | ||
429 | 1 38400 900 79.4 38400 36433.8 94 | ||
430 | 1 38400 600 82.4 38400 35107.3 91 | ||
431 | 2 19200 900 84.4 38400 34275.4 89 | ||
432 | 1 38400 400 86.8 38400 33327.6 86 | ||
433 | 2 19200 600 87.6 38400 33023.3 85 | ||
434 | 2 19200 400 91.2 38400 31719.7 82 | ||
435 | 4 9600 900 94.7 38400 30547.4 79 | ||
436 | 4 9600 400 106 38400 27290.9 71 | ||
437 | 4 9600 600 110 38400 26298.5 68 | ||
438 | 3 9600 900 118 28800 24515.6 85 | ||
439 | 3 9600 600 120 28800 24107 83 | ||
440 | 3 9600 400 131 28800 22082.7 76 | ||
441 | 1 19200 900 155 19200 18663.5 97 | ||
442 | 1 19200 600 161 19200 17968 93 | ||
443 | 1 19200 400 170 19200 17016.7 88 | ||
444 | 2 9600 600 176 19200 16436.6 85 | ||
445 | 2 9600 900 180 19200 16071.3 83 | ||
446 | 2 9600 400 181 19200 15982.5 83 | ||
447 | 1 9600 900 305 9600 9484.72 98 | ||
448 | 1 9600 600 314 9600 9212.87 95 | ||
449 | 1 9600 400 332 9600 8713.37 90 | ||
450 | |||
451 | |||
452 | |||
453 | |||
454 | |||
455 | 5.2. Anthony Healy's Report | ||
456 | |||
457 | |||
458 | |||
459 | |||
460 | |||
461 | |||
462 | |||
463 | Date: Mon, 13 Feb 1995 16:17:29 +1100 (EST) | ||
464 | From: Antony Healey <ahealey@st.nepean.uws.edu.au> | ||
465 | To: Simon Janes <guru@ncm.com> | ||
466 | Subject: Re: Load Balancing | ||
467 | |||
468 | Hi Simon, | ||
469 | I've installed your patch and it works great. I have trialed | ||
470 | it over twin SL/IP lines, just over null modems, but I was | ||
471 | able to data at over 48Kb/s [ISDN link -Simon]. I managed a | ||
472 | transfer of up to 7.5 Kbyte/s on one go, but averaged around | ||
473 | 6.4 Kbyte/s, which I think is pretty cool. :) | ||
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