diff options
Diffstat (limited to 'Documentation/networking/eql.rst')
| -rw-r--r-- | Documentation/networking/eql.rst | 373 |
1 files changed, 373 insertions, 0 deletions
diff --git a/Documentation/networking/eql.rst b/Documentation/networking/eql.rst new file mode 100644 index 000000000000..a628c4c81166 --- /dev/null +++ b/Documentation/networking/eql.rst @@ -0,0 +1,373 @@ +.. SPDX-License-Identifier: GPL-2.0 + +========================================== +EQL Driver: Serial IP Load Balancing HOWTO +========================================== + + Simon "Guru Aleph-Null" Janes, simon@ncm.com + + v1.1, February 27, 1995 + + This is the manual for the EQL device driver. EQL is a software device + that lets you load-balance IP serial links (SLIP or uncompressed PPP) + to increase your bandwidth. It will not reduce your latency (i.e. ping + times) except in the case where you already have lots of traffic on + your link, in which it will help them out. This driver has been tested + with the 1.1.75 kernel, and is known to have patched cleanly with + 1.1.86. Some testing with 1.1.92 has been done with the v1.1 patch + which was only created to patch cleanly in the very latest kernel + source trees. (Yes, it worked fine.) + +1. Introduction +=============== + + Which is worse? A huge fee for a 56K leased line or two phone lines? + It's probably the former. If you find yourself craving more bandwidth, + and have a ISP that is flexible, it is now possible to bind modems + together to work as one point-to-point link to increase your + bandwidth. All without having to have a special black box on either + side. + + + The eql driver has only been tested with the Livingston PortMaster-2e + terminal server. I do not know if other terminal servers support load- + balancing, but I do know that the PortMaster does it, and does it + almost as well as the eql driver seems to do it (-- Unfortunately, in + my testing so far, the Livingston PortMaster 2e's load-balancing is a + good 1 to 2 KB/s slower than the test machine working with a 28.8 Kbps + and 14.4 Kbps connection. However, I am not sure that it really is + the PortMaster, or if it's Linux's TCP drivers. I'm told that Linux's + TCP implementation is pretty fast though.--) + + + I suggest to ISPs out there that it would probably be fair to charge + a load-balancing client 75% of the cost of the second line and 50% of + the cost of the third line etc... + + + Hey, we can all dream you know... + + +2. Kernel Configuration +======================= + + Here I describe the general steps of getting a kernel up and working + with the eql driver. From patching, building, to installing. + + +2.1. Patching The Kernel +------------------------ + + If you do not have or cannot get a copy of the kernel with the eql + driver folded into it, get your copy of the driver from + ftp://slaughter.ncm.com/pub/Linux/LOAD_BALANCING/eql-1.1.tar.gz. + Unpack this archive someplace obvious like /usr/local/src/. It will + create the following files:: + + -rw-r--r-- guru/ncm 198 Jan 19 18:53 1995 eql-1.1/NO-WARRANTY + -rw-r--r-- guru/ncm 30620 Feb 27 21:40 1995 eql-1.1/eql-1.1.patch + -rwxr-xr-x guru/ncm 16111 Jan 12 22:29 1995 eql-1.1/eql_enslave + -rw-r--r-- guru/ncm 2195 Jan 10 21:48 1995 eql-1.1/eql_enslave.c + + Unpack a recent kernel (something after 1.1.92) someplace convenient + like say /usr/src/linux-1.1.92.eql. Use symbolic links to point + /usr/src/linux to this development directory. + + + Apply the patch by running the commands:: + + cd /usr/src + patch </usr/local/src/eql-1.1/eql-1.1.patch + + +2.2. Building The Kernel +------------------------ + + After patching the kernel, run make config and configure the kernel + for your hardware. + + + After configuration, make and install according to your habit. + + +3. Network Configuration +======================== + + So far, I have only used the eql device with the DSLIP SLIP connection + manager by Matt Dillon (-- "The man who sold his soul to code so much + so quickly."--) . How you configure it for other "connection" + managers is up to you. Most other connection managers that I've seen + don't do a very good job when it comes to handling more than one + connection. + + +3.1. /etc/rc.d/rc.inet1 +----------------------- + + In rc.inet1, ifconfig the eql device to the IP address you usually use + for your machine, and the MTU you prefer for your SLIP lines. One + could argue that MTU should be roughly half the usual size for two + modems, one-third for three, one-fourth for four, etc... But going + too far below 296 is probably overkill. Here is an example ifconfig + command that sets up the eql device:: + + ifconfig eql 198.67.33.239 mtu 1006 + + Once the eql device is up and running, add a static default route to + it in the routing table using the cool new route syntax that makes + life so much easier:: + + route add default eql + + +3.2. Enslaving Devices By Hand +------------------------------ + + Enslaving devices by hand requires two utility programs: eql_enslave + and eql_emancipate (-- eql_emancipate hasn't been written because when + an enslaved device "dies", it is automatically taken out of the queue. + I haven't found a good reason to write it yet... other than for + completeness, but that isn't a good motivator is it?--) + + + The syntax for enslaving a device is "eql_enslave <master-name> + <slave-name> <estimated-bps>". Here are some example enslavings:: + + eql_enslave eql sl0 28800 + eql_enslave eql ppp0 14400 + eql_enslave eql sl1 57600 + + When you want to free a device from its life of slavery, you can + either down the device with ifconfig (eql will automatically bury the + dead slave and remove it from its queue) or use eql_emancipate to free + it. (-- Or just ifconfig it down, and the eql driver will take it out + for you.--):: + + eql_emancipate eql sl0 + eql_emancipate eql ppp0 + eql_emancipate eql sl1 + + +3.3. DSLIP Configuration for the eql Device +------------------------------------------- + + The general idea is to bring up and keep up as many SLIP connections + as you need, automatically. + + +3.3.1. /etc/slip/runslip.conf +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + + Here is an example runslip.conf:: + + name sl-line-1 + enabled + baud 38400 + mtu 576 + ducmd -e /etc/slip/dialout/cua2-288.xp -t 9 + command eql_enslave eql $interface 28800 + address 198.67.33.239 + line /dev/cua2 + + name sl-line-2 + enabled + baud 38400 + mtu 576 + ducmd -e /etc/slip/dialout/cua3-288.xp -t 9 + command eql_enslave eql $interface 28800 + address 198.67.33.239 + line /dev/cua3 + + +3.4. Using PPP and the eql Device +--------------------------------- + + I have not yet done any load-balancing testing for PPP devices, mainly + because I don't have a PPP-connection manager like SLIP has with + DSLIP. I did find a good tip from LinuxNET:Billy for PPP performance: + make sure you have asyncmap set to something so that control + characters are not escaped. + + + I tried to fix up a PPP script/system for redialing lost PPP + connections for use with the eql driver the weekend of Feb 25-26 '95 + (Hereafter known as the 8-hour PPP Hate Festival). Perhaps later this + year. + + +4. About the Slave Scheduler Algorithm +====================================== + + The slave scheduler probably could be replaced with a dozen other + things and push traffic much faster. The formula in the current set + up of the driver was tuned to handle slaves with wildly different + bits-per-second "priorities". + + + All testing I have done was with two 28.8 V.FC modems, one connecting + at 28800 bps or slower, and the other connecting at 14400 bps all the + time. + + + One version of the scheduler was able to push 5.3 K/s through the + 28800 and 14400 connections, but when the priorities on the links were + very wide apart (57600 vs. 14400) the "faster" modem received all + traffic and the "slower" modem starved. + + +5. Testers' Reports +=================== + + Some people have experimented with the eql device with newer + kernels (than 1.1.75). I have since updated the driver to patch + cleanly in newer kernels because of the removal of the old "slave- + balancing" driver config option. + + + - icee from LinuxNET patched 1.1.86 without any rejects and was able + to boot the kernel and enslave a couple of ISDN PPP links. + +5.1. Randolph Bentson's Test Report +----------------------------------- + + :: + + From bentson@grieg.seaslug.org Wed Feb 8 19:08:09 1995 + Date: Tue, 7 Feb 95 22:57 PST + From: Randolph Bentson <bentson@grieg.seaslug.org> + To: guru@ncm.com + Subject: EQL driver tests + + + I have been checking out your eql driver. (Nice work, that!) + Although you may already done this performance testing, here + are some data I've discovered. + + Randolph Bentson + bentson@grieg.seaslug.org + +------------------------------------------------------------------ + + + A pseudo-device driver, EQL, written by Simon Janes, can be used + to bundle multiple SLIP connections into what appears to be a + single connection. This allows one to improve dial-up network + connectivity gradually, without having to buy expensive DSU/CSU + hardware and services. + + I have done some testing of this software, with two goals in + mind: first, to ensure it actually works as described and + second, as a method of exercising my device driver. + + The following performance measurements were derived from a set + of SLIP connections run between two Linux systems (1.1.84) using + a 486DX2/66 with a Cyclom-8Ys and a 486SLC/40 with a Cyclom-16Y. + (Ports 0,1,2,3 were used. A later configuration will distribute + port selection across the different Cirrus chips on the boards.) + Once a link was established, I timed a binary ftp transfer of + 289284 bytes of data. If there were no overhead (packet headers, + inter-character and inter-packet delays, etc.) the transfers + would take the following times:: + + bits/sec seconds + 345600 8.3 + 234600 12.3 + 172800 16.7 + 153600 18.8 + 76800 37.6 + 57600 50.2 + 38400 75.3 + 28800 100.4 + 19200 150.6 + 9600 301.3 + + A single line running at the lower speeds and with large packets + comes to within 2% of this. Performance is limited for the higher + speeds (as predicted by the Cirrus databook) to an aggregate of + about 160 kbits/sec. The next round of testing will distribute + the load across two or more Cirrus chips. + + The good news is that one gets nearly the full advantage of the + second, third, and fourth line's bandwidth. (The bad news is + that the connection establishment seemed fragile for the higher + speeds. Once established, the connection seemed robust enough.) + + ====== ======== === ======== ======= ======= === + #lines speed mtu seconds theory actual %of + kbit/sec duration speed speed max + ====== ======== === ======== ======= ======= === + 3 115200 900 _ 345600 + 3 115200 400 18.1 345600 159825 46 + 2 115200 900 _ 230400 + 2 115200 600 18.1 230400 159825 69 + 2 115200 400 19.3 230400 149888 65 + 4 57600 900 _ 234600 + 4 57600 600 _ 234600 + 4 57600 400 _ 234600 + 3 57600 600 20.9 172800 138413 80 + 3 57600 900 21.2 172800 136455 78 + 3 115200 600 21.7 345600 133311 38 + 3 57600 400 22.5 172800 128571 74 + 4 38400 900 25.2 153600 114795 74 + 4 38400 600 26.4 153600 109577 71 + 4 38400 400 27.3 153600 105965 68 + 2 57600 900 29.1 115200 99410.3 86 + 1 115200 900 30.7 115200 94229.3 81 + 2 57600 600 30.2 115200 95789.4 83 + 3 38400 900 30.3 115200 95473.3 82 + 3 38400 600 31.2 115200 92719.2 80 + 1 115200 600 31.3 115200 92423 80 + 2 57600 400 32.3 115200 89561.6 77 + 1 115200 400 32.8 115200 88196.3 76 + 3 38400 400 33.5 115200 86353.4 74 + 2 38400 900 43.7 76800 66197.7 86 + 2 38400 600 44 76800 65746.4 85 + 2 38400 400 47.2 76800 61289 79 + 4 19200 900 50.8 76800 56945.7 74 + 4 19200 400 53.2 76800 54376.7 70 + 4 19200 600 53.7 76800 53870.4 70 + 1 57600 900 54.6 57600 52982.4 91 + 1 57600 600 56.2 57600 51474 89 + 3 19200 900 60.5 57600 47815.5 83 + 1 57600 400 60.2 57600 48053.8 83 + 3 19200 600 62 57600 46658.7 81 + 3 19200 400 64.7 57600 44711.6 77 + 1 38400 900 79.4 38400 36433.8 94 + 1 38400 600 82.4 38400 35107.3 91 + 2 19200 900 84.4 38400 34275.4 89 + 1 38400 400 86.8 38400 33327.6 86 + 2 19200 600 87.6 38400 33023.3 85 + 2 19200 400 91.2 38400 31719.7 82 + 4 9600 900 94.7 38400 30547.4 79 + 4 9600 400 106 38400 27290.9 71 + 4 9600 600 110 38400 26298.5 68 + 3 9600 900 118 28800 24515.6 85 + 3 9600 600 120 28800 24107 83 + 3 9600 400 131 28800 22082.7 76 + 1 19200 900 155 19200 18663.5 97 + 1 19200 600 161 19200 17968 93 + 1 19200 400 170 19200 17016.7 88 + 2 9600 600 176 19200 16436.6 85 + 2 9600 900 180 19200 16071.3 83 + 2 9600 400 181 19200 15982.5 83 + 1 9600 900 305 9600 9484.72 98 + 1 9600 600 314 9600 9212.87 95 + 1 9600 400 332 9600 8713.37 90 + ====== ======== === ======== ======= ======= === + +5.2. Anthony Healy's Report +--------------------------- + + :: + + Date: Mon, 13 Feb 1995 16:17:29 +1100 (EST) + From: Antony Healey <ahealey@st.nepean.uws.edu.au> + To: Simon Janes <guru@ncm.com> + Subject: Re: Load Balancing + + Hi Simon, + I've installed your patch and it works great. I have trialed + it over twin SL/IP lines, just over null modems, but I was + able to data at over 48Kb/s [ISDN link -Simon]. I managed a + transfer of up to 7.5 Kbyte/s on one go, but averaged around + 6.4 Kbyte/s, which I think is pretty cool. :) |