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Editing of new "Linux-Networking" guide. This copy is not to be distributed. Its just a draft to give people an idea as to the format of the new document and a backup just in case my laptop dies. 

Binh.
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binh 2004-11-19 13:31:14 +00:00
parent 7839c0b306
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2
LDP/guide/docbook/Linux-Networking/Foreward.xml
View File

@ -375,6 +375,6 @@ connection issue. The administrator can proceed in one of either two ways.
He can move upwards through the hierarchy or downwards, either way he is
eliminating possible issues at each point which therefore reduces the
possible number of problems at each point. The purpose of each layer will
be explained below.
be explained in the sections on the TCP/IP and OSI networking models.
</sect1>

1
LDP/guide/docbook/Linux-Networking/Glossary.xml
View File

@ -1,4 +1,5 @@
<glossary id="Glossary">
<title>Glossary</title>
ARPA

935
LDP/guide/docbook/Linux-Networking/Leased-Line.xml
View File

@ -2,491 +2,486 @@
<title>Leased-Line</title>
_______________________________________________________________________________
<sect>
<para>
Configuring your modem and pppd to use a 2 wire twisted pair leased
line.
</para>
1.2. What is a leased line
<para>
Any fixed, that is permanent, point to point data communications link,
which is leased from a telco or similar organisation. The leased line
involves cables, such as twisted pair, coax or fiber optic, and may
involve all sorts of other hardware such as (pupin) coils,
transformers, amplifiers and regenerators.
</para>
<para>
This document deals with:
Configuring your modem and pppd to use a 2 wire twisted pair
leased line.
</para>
<para>
This document does NOT deal with:
SLIP, getting or installing pppd, synchronous data
communication, baseband modems, xDSL.
</para>
1.3. Assumptions
<para>
You should already have a working pppd on your system. You also need
Minicom or a similar program to configure your modems.
</para>
2. Modem
<para>
A leased line is not connected to a telephone exchange and does not
provide DC power, dial tone, busy tone or ring signal. This means that
your modems are on their own and have to be able to deal with this
situation.
</para>
<para>
You should have 2 identical (including firmware version) external
modems supporting both leased line and dumb mode. Make sure your
modems can actually do this! Also make sure your modem is properly
documented. You also need:
</para>
· 2 fully wired shielded RS232 cables. The shield should be connected
to the connector shell (not pin 1) at both ends (not at one end).
· A RS232 test plug may be handy for test purposes.
· 2 RJ11 cords, one for each end of the leased line.
· A basic understanding of `AT' commands.
2.1. Modem Configuration
<para>
A note on modem configuration and init strings in general: Configure
your modem software such as minicom or (m)getty to use the highest
possible speed; 57600 bps for 14k4 and 115200 bps for 28k8 or faster
modems. Lots of people use very long and complicated init strings,
often starting with AT&F and containing lots of modem brand and -type
specific commands. This however is needlessly complicated. Most
programs feel happy with the same modem settings, so why not write
these settings in the non volatile memory of all your modems, and only
use `ATZ' as an init string in all your programs. This way you can
swap or upgrade your modems without ever having to reconfigure any of
your software.
</para>
<para>
Most programs require you to use the following settings;
</para>
· Fixed baud rate (no auto baud)
· Hardware bidirectional RTS-CTS flow control (no x-on/x-off)
· 8 Bits, no parity, 1 stopbit
· The modem should produce the TRUE DCD status (&C1)
· The modem should NOT ignore the DTR status (&D2 or &D3)
<para>
Check this with AT&V or AT&Ix (consult your modem documentation)
</para>
<para>
These settings are not necessarily the same as the default factory
profile (&F), so starting an init string with AT&F is probably not a
good idea in the first place. The smart thing to do is probably to use
AT&F only when you have reason to believe that the modem setup stored
in the non volatile memory is really screwed up. If you think you
have found the right setup for your modems, write it to non volatile
memory with AT&W and test it thoroughly with Z-modem file transfers of
both ASCII text and binary files. Only if all of this works perfectly
should you configure your modems for leased line.
</para>
<para>
Find out how to put your modem into dumb mode and, more importantly,
how to get it out of dumb mode; The modem can only be reconfigured
when it is not in dumb mode. Make sure you actually configure your
modems at the highest possible speed. Once in dumb mode it will
ignore all `AT' commands and consequently will not adjust its speed to
that of the COM port, but will use the speed at which it was
configured instead (this speed is stored in a S-register by the AT&W
command).
</para>
<para>
Now configure your modem as follows;
</para>
· Reset on DTR toggle (&D3, this is sometimes a S register). This
setting is required by some ISP's!
· Leased line mode (&L1 or &L2, consult your modem documentation)
· The remote modem auto answer (S0=1), the local originate (S0=0)
· Disable result codes (Q1, sometimes the dumb mode does this for
you)
· Dumb mode (\D1 or %D1, this is sometimes a jumper) In dumb mode the
modem will ignore all AT commands (sometimes you need to disable
the ESC char as well).
<para>
Write the configuration to non-volatile memory (&W).
</para>
2.2. Test
<para>
Now connect the modems to 2 computers using the RS232 cables and
connect the modems to each other using a RJ11 lead. Use a modem
program such as Minicom (Linux), procom or telix (DOS) on both
computers to test the modems. You should be able to type text from
one computer to the other and vice versa. If the screen produces
garbage check your COM port speed and other settings. Now disconnect
and reconnect the RJ11 cord. Wait for the connection to reestablish
itself. Disconnect and reconnect the RS232 cables, switch the modems
on and off, stop and restart Minicom. The modems should always
reconnect at the highest possible speed (some modems have speed
indicator leds). Check whether the modems actually ignores the ESC
(+++) character. If necessary disable the ESC character.
</para>
<para>
If all of this works you may want to reconfigure your modems; Switch
off the sound at the remote modem (M0) and put the local modem at low
volume (L1).
</para>
2.3. Examples
2.3.1. Hi-Tech
<para>
This is a rather vague `no name clone modem'. Its config string is
however typical and should work on most modems.
</para>
<para>
Originate (local):
ATL1&C1&D3&L2%D1&W&W1
</para>
<para>
Answer (remote):
ATM0L1&C1&D3&L2%D1S0=1&W&W1
</para>
2.3.2. Tornado FM 228 E
<para>
This is what should work;
</para>
<para>
Originate (local):
ATB15L1Q1&C1&D3&L2&W&W1
</para>
<para>
Answer (remote):
ATM0B15M0Q1&C1&D3&L2S0=1&W&W1
</para>
<para>
Move the dumb jumper from position 2-3 to 1-2.
</para>
<para>
Due to a firmware bug, the modems will only connect after being hard
reset (power off and on) while DTR is high. I designed a circuit which
hard resets the modem on the low to high transition of DTR. The
FreeBSD pppd however, isn't very happy about this. By combining the
setting &D0 with a circuit which resets on the high to low transition
instead, this problem can be avoided.
</para>
2.3.3. Tron DF
<para>
The ESC char should be disabled by setting S2 > 127;
</para>
<para>
Originate:
ATL1&L1Q1&C1&D3S2=171\D1&W
</para>
<para>
Answer:
ATM0&L2Q1&C1&D3S0=1S2=171\D1&W
</para>
2.3.4. US Robotics Courier V-Everything
<para>
The USR Sportster and USR Courier-I do not support leased line. You
need the Courier V-everything version for this job. There is a
webpage on the USR site `explaining' how to set-up your Courier for
leased line. However, if you follow these instructions you will end up
with a completely brain dead modem, which can not be controlled or
monitored by your pppd.
</para>
<para>
The USR Courier can be configured with dip switches, however you need
to feed it the config string first. First make sure it uses the right
factory profile. Unlike most other modems it has three; &F0, &F1 and
&F2. The default, which is also the one you should use, is &F1. If you
send it an AT&F, however it will load the factory profile &F0! For
the reset on DTR toggle you set bit 0 of S register 13. This means you
have to set S13 to 1. Furthermore you need set it to leased line mode
with &L1; ATS13=1&L1&W The dip switches are all default except for the
following:
<para>
Leased line Mini HOWTO
Configuring your modem and pppd to use a 2 wire twisted pair leased
line.
______________________________________________________________________
Table of Contents
1. Introduction
1.1 Copyright and License
1.2 What is a leased line
1.3 Assumptions
2. Modem
2.1 Modem Configuration
2.2 Test
2.3 Examples
2.3.1 Hi-Tech
2.3.2 Tornado FM 228 E
2.3.3 Tron DF
2.3.4 US Robotics Courier V-Everything
3. PPPD
3.1 Configuration
3.2 Scripts
3.2.1 Starting the pppd and keeping it alive
3.2.2 Setting the routes
3.3 Test
______________________________________________________________________
The most recent (beta) version of this HOWTO can be found at:
http://www.sput.nl/software/leased-line/
1. Introduction
1.1. Copyright and License
This document is distributed under the terms of the GNU Free
Documentation License. You should have received a copy along with it.
If not, it is available from http://www.fsf.org/licenses/fdl.html.
1.2. What is a leased line
Any fixed, that is permanent, point to point data communications link,
which is leased from a telco or similar organisation. The leased line
involves cables, such as twisted pair, coax or fiber optic, and may
involve all sorts of other hardware such as (pupin) coils,
transformers, amplifiers and regenerators.
This document deals with:
Configuring your modem and pppd to use a 2 wire twisted pair
leased line.
This document does NOT deal with:
SLIP, getting or installing pppd, synchronous data
communication, baseband modems, xDSL.
1.3. Assumptions
You should already have a working pppd on your system. You also need
Minicom or a similar program to configure your modems.
2. Modem
A leased line is not connected to a telephone exchange and does not
provide DC power, dial tone, busy tone or ring signal. This means that
your modems are on their own and have to be able to deal with this
situation.
You should have 2 identical (including firmware version) external
modems supporting both leased line and dumb mode. Make sure your
modems can actually do this! Also make sure your modem is properly
documented. You also need:
· 2 fully wired shielded RS232 cables. The shield should be connected
to the connector shell (not pin 1) at both ends (not at one end).
· A RS232 test plug may be handy for test purposes.
· 2 RJ11 cords, one for each end of the leased line.
· A basic understanding of `AT' commands.
2.1. Modem Configuration
A note on modem configuration and init strings in general: Configure
your modem software such as minicom or (m)getty to use the highest
possible speed; 57600 bps for 14k4 and 115200 bps for 28k8 or faster
modems. Lots of people use very long and complicated init strings,
often starting with AT&F and containing lots of modem brand and -type
specific commands. This however is needlessly complicated. Most
programs feel happy with the same modem settings, so why not write
these settings in the non volatile memory of all your modems, and only
use `ATZ' as an init string in all your programs. This way you can
swap or upgrade your modems without ever having to reconfigure any of
your software.
Most programs require you to use the following settings;
· Fixed baud rate (no auto baud)
· Hardware bidirectional RTS-CTS flow control (no x-on/x-off)
· 8 Bits, no parity, 1 stopbit
· The modem should produce the TRUE DCD status (&C1)
· The modem should NOT ignore the DTR status (&D2 or &D3)
Check this with AT&V or AT&Ix (consult your modem documentation)
These settings are not necessarily the same as the default factory
profile (&F), so starting an init string with AT&F is probably not a
good idea in the first place. The smart thing to do is probably to use
AT&F only when you have reason to believe that the modem setup stored
in the non volatile memory is really screwed up. If you think you
have found the right setup for your modems, write it to non volatile
memory with AT&W and test it thoroughly with Z-modem file transfers of
both ASCII text and binary files. Only if all of this works perfectly
should you configure your modems for leased line.
Find out how to put your modem into dumb mode and, more importantly,
how to get it out of dumb mode; The modem can only be reconfigured
when it is not in dumb mode. Make sure you actually configure your
modems at the highest possible speed. Once in dumb mode it will
ignore all `AT' commands and consequently will not adjust its speed to
that of the COM port, but will use the speed at which it was
configured instead (this speed is stored in a S-register by the AT&W
command).
Now configure your modem as follows;
· Reset on DTR toggle (&D3, this is sometimes a S register). This
setting is required by some ISP's!
· Leased line mode (&L1 or &L2, consult your modem documentation)
· The remote modem auto answer (S0=1), the local originate (S0=0)
· Disable result codes (Q1, sometimes the dumb mode does this for
you)
· Dumb mode (\D1 or %D1, this is sometimes a jumper) In dumb mode the
modem will ignore all AT commands (sometimes you need to disable
the ESC char as well).
Write the configuration to non-volatile memory (&W).
2.2. Test
Now connect the modems to 2 computers using the RS232 cables and
connect the modems to each other using a RJ11 lead. Use a modem
program such as Minicom (Linux), procom or telix (DOS) on both
computers to test the modems. You should be able to type text from
one computer to the other and vice versa. If the screen produces
garbage check your COM port speed and other settings. Now disconnect
and reconnect the RJ11 cord. Wait for the connection to reestablish
itself. Disconnect and reconnect the RS232 cables, switch the modems
on and off, stop and restart Minicom. The modems should always
reconnect at the highest possible speed (some modems have speed
indicator leds). Check whether the modems actually ignores the ESC
(+++) character. If necessary disable the ESC character.
If all of this works you may want to reconfigure your modems; Switch
off the sound at the remote modem (M0) and put the local modem at low
volume (L1).
2.3. Examples
2.3.1. Hi-Tech
This is a rather vague `no name clone modem'. Its config string is
however typical and should work on most modems.
Originate (local):
ATL1&C1&D3&L2%D1&W&W1
Answer (remote):
ATM0L1&C1&D3&L2%D1S0=1&W&W1
2.3.2. Tornado FM 228 E
This is what should work;
Originate (local):
ATB15L1Q1&C1&D3&L2&W&W1
Answer (remote):
ATM0B15M0Q1&C1&D3&L2S0=1&W&W1
Move the dumb jumper from position 2-3 to 1-2.
Due to a firmware bug, the modems will only connect after being hard
reset (power off and on) while DTR is high. I designed a circuit which
hard resets the modem on the low to high transition of DTR. The
FreeBSD pppd however, isn't very happy about this. By combining the
setting &D0 with a circuit which resets on the high to low transition
instead, this problem can be avoided.
2.3.3. Tron DF
The ESC char should be disabled by setting S2 > 127;
Originate:
ATL1&L1Q1&C1&D3S2=171\D1&W
Answer:
ATM0&L2Q1&C1&D3S0=1S2=171\D1&W
2.3.4. US Robotics Courier V-Everything
The USR Sportster and USR Courier-I do not support leased line. You
need the Courier V-everything version for this job. There is a
webpage on the USR site `explaining' how to set-up your Courier for
leased line. However, if you follow these instructions you will end up
with a completely brain dead modem, which can not be controlled or
monitored by your pppd.
The USR Courier can be configured with dip switches, however you need
to feed it the config string first. First make sure it uses the right
factory profile. Unlike most other modems it has three; &F0, &F1 and
&F2. The default, which is also the one you should use, is &F1. If you
send it an AT&F, however it will load the factory profile &F0! For
the reset on DTR toggle you set bit 0 of S register 13. This means you
have to set S13 to 1. Furthermore you need set it to leased line mode
with &L1; ATS13=1&L1&W The dip switches are all default except for the
following:
3 OFF Disable result codes
4 ON Disable offline commands
5 ON For originate, OFF For answer
8 OFF Dumb mode
3. PPPD
You need a pppd (Point to Point Protocol Daemon) and a reasonable
knowledge of how it works. Consult the relevant RFC's or the Linux PPP
HOWTO if necessary. Since you are not going to use a login procedure,
you don't use (m)getty and you do not need a (fake) user associated
with the pppd controlling your link. You are not going to dial so you
don't need any chat scripts either. In fact, the modem circuit and
configuration you have just build, are rather like a fully wired null
modem cable. This means you have to configure your pppd the same way
as you would with a null modem cable.
For a reliable link, your setup should meet the following criteria;
· Shortly after booting your system, pppd should raise the DTR signal
in your RS232 port, wait for DCD to go up, and negotiate the link.
· If the remote system is down, pppd should wait until it is up
again.
· If the link is up and then goes down, pppd should reset the modem
(it does this by dropping and then raising DTR), and then try to
reconnect.
· If the quality of the link deteriorates too much, pppd should reset
the modem and then reestablish the link.
· If the process controlling the link, that is the pppd, dies, a
watchdog should restart the pppd.
3.1. Configuration
Suppose the modem is connected to COM2, the local IP address is
`Loc_Ip' and the remote IP address is `Rem_Ip'. We want to use 576 as
our MTU. The /etc/ppp/options.ttyS1 would now be:
crtscts
mru 576
mtu 576
passive
Loc_Ip:Rem_Ip
-chap
modem
#noauth
-pap
persist
Stuff like `asyncmap 0', `lock', `modem' and `-detach' are probably
already in /etc/ppp/options. If not, add them to your
/etc/ppp/options.ttyS1. So, if the local system is 192.168.1.1 and
the remote system is 10.1.1.1, then /etc/ppp/options.ttyS1 on the
local system would be:
crtscts
mru 576
mtu 576
passive
192.168.1.1:10.1.1.1
-chap
modem
#noauth
-pap
persist
The options.ttyS1 on the remote system would be:
crtscts
mru 576
mtu 576
passive
10.1.1.1:192.168.1.1
-chap
modem
#noauth
-pap
persist
The passive option limits the number of (re)connection attempts. The
persist option will keep pppd alive in case of a disconnect or when it
can't connect in the first place. If you telnet a lot while doing
filetransfers (FTP or webbrowsing) at the same time, you might want to
use a smaller MTU and MRU such as 296. This will make the remote sys­
tem more responsive. If you don't care much about telnetting during
FTP, you could set the MTU and MRU to 1500. Keep in mind though, that
UDP cannot be fragmented. Speakfreely for instance uses 512 byte UDP
packets. So the minimum MTU for speakfreely is 552 bytes. The noauth
option may be necessary with some newer distributions.
3.2. Scripts
3.2.1. Starting the pppd and keeping it alive
You could start the pppd form a boot (rc) script. However, if you do
this, and the pppd dies, you are without a link. A more stable
solution, is to start the pppd from /etc/inittab;
s1:23:respawn:/usr/sbin/pppd /dev/ttyS1 115200
This way, the pppd will be restarted if it dies. Make sure you have a
`-detach' option (nodetach on newer systems) though, otherwise inittab
will start numerous instances of pppd, will complaining about
`respawning too fast'.
Note: Some older systems will not accept the speed `115200'. In this
case you will have to set the speed to 38400 en set the `spd_vhi' flag
with setserial. Some systems expect you to use a `cua' instead of
`ttyS' device.
3.2.2. Setting the routes
The default route can be set with the defaultroute option or with the
/etc/ppp/ip-up script;
#!/bin/bash
case $2 in
/dev/ttyS1)
/sbin/route add -net 0.0.0.0 gw Rem_Ip netmask 0.0.0.0
;;
esac
Ip-up can also be used to sync your clock using netdate.
Of course the route set in ip-up is not necessarily the default route.
Your ip-up sets the route to the remote network while the ip-up script
on the remote system sets the route to your network. If your network
is 192.168.1.0 and your ppp interface 192.168.1.1, the ip-up script on
the remote machine looks like this;
#!/bin/bash
case $2 in
<para>
3 OFF Disable result codes
4 ON Disable offline commands
5 ON For originate, OFF For answer
8 OFF Dumb mode
</para>
3. PPPD
<para>
You need a pppd (Point to Point Protocol Daemon) and a reasonable
knowledge of how it works. Consult the relevant RFC's or the Linux PPP
HOWTO if necessary. Since you are not going to use a login procedure,
you don't use (m)getty and you do not need a (fake) user associated
with the pppd controlling your link. You are not going to dial so you
don't need any chat scripts either. In fact, the modem circuit and
configuration you have just build, are rather like a fully wired null
modem cable. This means you have to configure your pppd the same way
as you would with a null modem cable.
</para>
<para>
For a reliable link, your setup should meet the following criteria;
</para>
· Shortly after booting your system, pppd should raise the DTR signal
in your RS232 port, wait for DCD to go up, and negotiate the link.
· If the remote system is down, pppd should wait until it is up
again.
· If the link is up and then goes down, pppd should reset the modem
(it does this by dropping and then raising DTR), and then try to
reconnect.
· If the quality of the link deteriorates too much, pppd should reset
the modem and then reestablish the link.
· If the process controlling the link, that is the pppd, dies, a
watchdog should restart the pppd.
3.1. Configuration
<para>
Suppose the modem is connected to COM2, the local IP address is
`Loc_Ip' and the remote IP address is `Rem_Ip'. We want to use 576 as
our MTU. The /etc/ppp/options.ttyS1 would now be:
</para>
<para>
<screen>
crtscts
mru 576
mtu 576
passive
Loc_Ip:Rem_Ip
-chap
modem
#noauth
-pap
persist
</screen>
</para>
<para>
Stuff like `asyncmap 0', `lock', `modem' and `-detach' are probably
already in /etc/ppp/options. If not, add them to your
/etc/ppp/options.ttyS1. So, if the local system is 192.168.1.1 and
the remote system is 10.1.1.1, then /etc/ppp/options.ttyS1 on the
local system would be:
</para>
<para>
<screen>
crtscts
mru 576
mtu 576
passive
192.168.1.1:10.1.1.1
-chap
modem
#noauth
-pap
persist
</screen>
</para>
<para>
The options.ttyS1 on the remote system would be:
</para>
<para>
<screen>
crtscts
mru 576
mtu 576
passive
10.1.1.1:192.168.1.1
-chap
modem
#noauth
-pap
persist
</screen>
</para>
<para>
The passive option limits the number of (re)connection attempts. The
persist option will keep pppd alive in case of a disconnect or when it
can't connect in the first place. If you telnet a lot while doing
filetransfers (FTP or webbrowsing) at the same time, you might want to
use a smaller MTU and MRU such as 296. This will make the remote sys­
tem more responsive. If you don't care much about telnetting during
FTP, you could set the MTU and MRU to 1500. Keep in mind though, that
UDP cannot be fragmented. Speakfreely for instance uses 512 byte UDP
packets. So the minimum MTU for speakfreely is 552 bytes. The noauth
option may be necessary with some newer distributions.
</para>
3.2. Scripts
3.2.1. Starting the pppd and keeping it alive
<para>
You could start the pppd form a boot (rc) script. However, if you do
this, and the pppd dies, you are without a link. A more stable
solution, is to start the pppd from /etc/inittab;
</para>
<para>
<screen>
s1:23:respawn:/usr/sbin/pppd /dev/ttyS1 115200
</screen>
</para>
<para>
This way, the pppd will be restarted if it dies. Make sure you have a
`-detach' option (nodetach on newer systems) though, otherwise inittab
will start numerous instances of pppd, will complaining about
`respawning too fast'.
</para>
<para>
Note: Some older systems will not accept the speed `115200'. In this
case you will have to set the speed to 38400 en set the `spd_vhi' flag
with setserial. Some systems expect you to use a `cua' instead of
`ttyS' device.
</para>
3.2.2. Setting the routes
<para>
The default route can be set with the defaultroute option or with the
/etc/ppp/ip-up script;
</para>
<para>
<screen>
#!/bin/bash
case $2 in
/dev/ttyS1)
/sbin/route add -net 192.168.1.0 gw 192.168.1.1 netmask 255.255.255.0
;;
esac
/sbin/route add -net 0.0.0.0 gw Rem_Ip netmask 0.0.0.0
;;
esac
</screen>
</para>
<para>
Ip-up can also be used to sync your clock using netdate.
</para>
<para>
Of course the route set in ip-up is not necessarily the default route.
Your ip-up sets the route to the remote network while the ip-up script
on the remote system sets the route to your network. If your network
is 192.168.1.0 and your ppp interface 192.168.1.1, the ip-up script on
the remote machine looks like this;
</para>
The `case $2' and `/dev/ttyS1)' bits are there in case you use more
than one ppp link. Ip-up will run each time a link comes up, but only
the part between `/dev/ttySx)' and `;;' will be executed, setting the
right route for the right ttyS. You can find more about routing in
the Linux Networking HOWTO section on routing.
<para>
<screen>
#!/bin/bash
case $2 in
/dev/ttyS1)
/sbin/route add -net 192.168.1.0 gw 192.168.1.1 netmask 255.255.255.0
;;
esac
</screen>
</para>
3.3. Test
<para>
The `case $2' and `/dev/ttyS1)' bits are there in case you use more
than one ppp link. Ip-up will run each time a link comes up, but only
the part between `/dev/ttySx)' and `;;' will be executed, setting the
right route for the right ttyS. You can find more about routing in
the Linux Networking HOWTO section on routing.
</para>
Test the whole thing just like the modem test. If it works, get on
your bike and bring the remote modem to the remote side of your link.
If it doesn't work, one of the things you should check is the COM port
speed; Apparently, a common mistake is to configure the modems with
Minicom using one speed and then configure the pppd to use an other.
This will NOT work! You have to use the same speed all of the time!
3.3. Test
<para>
Test the whole thing just like the modem test. If it works, get on
your bike and bring the remote modem to the remote side of your link.
If it doesn't work, one of the things you should check is the COM port
speed; Apparently, a common mistake is to configure the modems with
Minicom using one speed and then configure the pppd to use an other.
This will NOT work! You have to use the same speed all of the time!
</para>
</sect>
<sect>
T1-T4
<para>
A T1 line is a high-speed, dedicated, point-to-point leased line that
includes 24 seperate 64 Kbps channles for voice and data. Other lines
of this type, called T-carrier lines, support larger numbers of channels.
T1 and T3 lines are the most commonly used.
</para>
A T1 line is a high-speed, dedicated, point-to-point leased line that includes 24 seperate
64 Kbps channles for voice and data. Other lines of this type, called T-carrier lines, support
larger numbers of channels. T1 and T3 lines are the most commonly used.
Carrier Channels Total Bandwidth
<para>
<screen>
Carrier Channels Total Bandwidth
T1 24 1.544 Mbps
T2 96 6.312 Mbps
T3 672 44.736 Mbps
T4 4032 274.176 Mbps
</screen>
</para>
While the specification for T-carrier lines does not mandate a particular media type, T1 and
T2 are typically carried on copper, and T3 and T4 typically use fiber optic media. DS1, DS2,
DS3, and DS4 are an alternate type of line equivalent to T1-T4, and typically use fiber optic
media.
<para>
While the specification for T-carrier lines does not mandate a particular
media type, T1 and T2 are typically carried on copper, and T3 and T4
typically use fiber optic media. DS1, DS2, DS3, and DS4 are an alternate
type of line equivalent to T1-T4, and typically use fiber optic media.
</para>
SONET (Synchronous Optical Network)
<para>
A leased-line system using fiber optic media to support data speeds up to
2.4 Gbps. SONET services are sold based on optical carier (OC) levels. OC
levels are calculated as multiples of the OC-1 speed, 51.840 Mbps. For
example, OC-3 level would correspond with a data speed of 155 Mbps and
OC-12 level would equate to a data transfer rate of 622 Mbps. OC-1 and
OC-3 are the most commonly used SONET lines.
</para>
A leased-line system using fiber optic media to support data speeds up to 2.4 Gbps. SONET
services are sold based on optical carier (OC) levels. OC levels are calculated as multiples
of the OC-1 speed, 51.840 Mbps. For example, OC-3 level would correspond with a data speed of
155 Mbps and OC-12 level would equate to a data transfer rate of 622 Mbps. OC-1 and OC-3
are the most commonly used SONET lines.
</sect1>
</sect>

320
LDP/guide/docbook/Linux-Networking/PLIP.xml
View File

@ -3,147 +3,183 @@
<title>PLIP</title>
<para>
7.2. PLIP for Linux-2.0
PLIP device names are `plip0', `plip1 and plip2.
Kernel Compile Options:
Network device support --->
<*> PLIP (parallel port) support
plip (Parallel Line IP), is like SLIP, in that it is used for
providing a point to point network connection between two machines,
except that it is designed to use the parallel printer ports on your
machine instead of the serial ports (a cabling diagram in included in
the cabling diagram section later in this document). Because it is
possible to transfer more than one bit at a time with a parallel port,
it is possible to attain higher speeds with the plip interface than
with a standard serial device. In addition, even the simplest of
parallel ports, printer ports, can be used in lieu of you having to
purchase comparatively expensive 16550AFN UART's for your serial
ports. PLIP uses a lot of CPU compared to a serial link and is most
certainly not a good option if you can obtain some cheap ethernet
cards, but it will work when nothing else is available and will work
quite well. You should expect a data transfer rate of about 20
kilobytes per second when a link is running well.
The PLIP device drivers competes with the parallel device driver for
the parallel port hardware. If you wish to use both drivers then you
should compile them both as modules to ensure that you are able to
select which port you want to use for PLIP and which ports you want
for the printer driver. Refer to the ``Mudules mini-HOWTO'' for more
information on kernel module configuration.
Please note that some laptops use chipsets that will not work with
PLIP because they do not allow some combinations of signals that PLIP
relies on, that printers don't use.
The Linux plip interface is compatible with the Crynwyr Packet Driver
PLIP and this will mean that you can connect your Linux machine to a
DOS machine running any other sort of tcp/ip software via plip.
In the 2.0.* series kernel the plip devices are mapped to i/o port and
IRQ as follows:
device i/o IRQ
------ ----- ---
plip0 0x3bc 5
plip1 0x378 7
plip2 0x278 2
If your parallel ports don't match any of the above combinations then
you can change the IRQ of a port using the ifconfig command using the
`irq' parameter (be sure to enable IRQ's on your printer ports in your
ROM BIOS if it supports this option). As an alternative, you can
specify ``io='' annd ``irq='' options on the insmod command line, if
you use modules. For example:
root# insmod plip.o io=0x288 irq=5
PLIP operation is controlled by two timeouts, whose default values are
probably ok in most cases. You will probably need to increase them if
you have an especially slow computer, in which case the timers to
increase are actually on the other computer. A program called
plipconfig exists that allows you to change these timer settings
without recompiling your kernel. It is supplied with many Linux
distributions.
To configure a plip interface, you will need to invoke the following
commands (or add them to your initialization scripts):
root# /sbin/ifconfig plip1 localplip pointopoint remoteplip
root# /sbin/route add remoteplip plip1
Here, the port being used is the one at I/O address 0x378; localplip
amd remoteplip are the names or IP addresses used over the PLIP cable.
I personally keep them in my /etc/hosts database:
# plip entries
192.168.3.1 localplip
192.168.3.2 remoteplip
The pointopoint parameter has the same meaning as for SLIP, in that it
specifies the address of the machine at the other end of the link.
In almost all respects you can treat a plip interface as though it
were a SLIP interface, except that neither dip nor slattach need be,
nor can be, used.
Further information on PLIP may be obtained from the ``PLIP mini-
HOWTO''.
7.3. PLIP for Linux-2.2
During development of the 2.1 kernel versions, support for the
parallel port was changed to a better setup.
Kernel Compile Options:
General setup --->
[*] Parallel port support
Network device support --->
<*> PLIP (parallel port) support
The new code for PLIP behaves like the old one (use the same ifconfig
and route commands as in the previous section, but initialization of
the device is different due to the advanced parallel port support.
The ``first'' PLIP device is always called ``plip0'', where first is
the first device detected by the system, similarly to what happens for
Ethernet devices. The actual parallel port being used is one of the
available ports, as shown in /proc/parport. For example, if you have
only one parallel port, you'll only have a directory called
/proc/parport/0.
If your kernel didn't detect the IRQ number used by your port,
``insmod plip'' will fail; in this case just write the right number to
/proc/parport/0/irq and reinvoke insmod.
Complete information about parallel port management is available in
the file Documentation/parport.txt, part of your kernel sources.
plip (Parallel Line IP), is like SLIP, in that it is used for
providing a point to point network connection between two machines,
except that it is designed to use the parallel printer ports on your
machine instead of the serial ports (a cabling diagram in included in
the cabling diagram section later in this document). Because it is
possible to transfer more than one bit at a time with a parallel port,
it is possible to attain higher speeds with the plip interface than
with a standard serial device. In addition, even the simplest of
parallel ports, printer ports, can be used in lieu of you having to
purchase comparatively expensive 16550AFN UART's for your serial
ports. PLIP uses a lot of CPU compared to a serial link and is most
certainly not a good option if you can obtain some cheap ethernet
cards, but it will work when nothing else is available and will work
quite well. You should expect a data transfer rate of about 20
kilobytes per second when a link is running well.
</para>
</sect1>
7.2. PLIP for Linux-2.0
<para>
PLIP device names are `plip0', `plip1 and plip2.
</para>
<para>
<screen>
Kernel Compile Options:
Network device support --->
<*> PLIP (parallel port) support
</screen>
</para>
<para>
The PLIP device drivers competes with the parallel device driver for
the parallel port hardware. If you wish to use both drivers then you
should compile them both as modules to ensure that you are able to
select which port you want to use for PLIP and which ports you want
for the printer driver. Refer to the ``Modules mini-HOWTO'' for more
information on kernel module configuration.
</para>
<para>
Please note that some laptops use chipsets that will not work with
PLIP because they do not allow some combinations of signals that PLIP
relies on, that printers don't use.
</para>
<para>
The Linux plip interface is compatible with the Crynwyr Packet Driver
PLIP and this will mean that you can connect your Linux machine to a
DOS machine running any other sort of tcp/ip software via plip.
</para>
<para>
In the 2.0.* series kernel the plip devices are mapped to i/o port and
IRQ as follows:
</para>
<para>
<screen>
device i/o IRQ
------ ----- ---
plip0 0x3bc 5
plip1 0x378 7
plip2 0x278 2
</screen>
</para>
<para>
If your parallel ports don't match any of the above combinations then
you can change the IRQ of a port using the ifconfig command using the
`irq' parameter (be sure to enable IRQ's on your printer ports in your
ROM BIOS if it supports this option). As an alternative, you can
specify ``io='' annd ``irq='' options on the insmod command line, if
you use modules. For example:
</para>
<para>
<screen>
root# insmod plip.o io=0x288 irq=5
</screen>
</para>
<para>
PLIP operation is controlled by two timeouts, whose default values are
probably ok in most cases. You will probably need to increase them if
you have an especially slow computer, in which case the timers to
increase are actually on the other computer. A program called
plipconfig exists that allows you to change these timer settings
without recompiling your kernel. It is supplied with many Linux
distributions.
</para>
<para>
To configure a plip interface, you will need to invoke the following
commands (or add them to your initialization scripts):
</para>
<para>
<screen>
root# /sbin/ifconfig plip1 localplip pointopoint remoteplip
root# /sbin/route add remoteplip plip1
</screen>
</para>
<para>
Here, the port being used is the one at I/O address 0x378; localplip
amd remoteplip are the names or IP addresses used over the PLIP cable.
I personally keep them in my /etc/hosts database:
</para>
<para>
<screen>
# plip entries
192.168.3.1 localplip
192.168.3.2 remoteplip
</screen>
</para>
<para>
The pointopoint parameter has the same meaning as for SLIP, in that it
specifies the address of the machine at the other end of the link.
</para>
<para>
In almost all respects you can treat a plip interface as though it
were a SLIP interface, except that neither dip nor slattach need be,
nor can be, used.
</para>
<para>
Further information on PLIP may be obtained from the ``PLIP mini-
HOWTO''.
</para>
7.3. PLIP for Linux-2.2
<para>
During development of the 2.1 kernel versions, support for the
parallel port was changed to a better setup.
</para>
<para>
<screen>
Kernel Compile Options:
General setup --->
[*] Parallel port support
Network device support --->
<*> PLIP (parallel port) support
</screen>
</para>
<para>
The new code for PLIP behaves like the old one (use the same ifconfig
and route commands as in the previous section, but initialization of
the device is different due to the advanced parallel port support.
</para>
<para>
The ``first'' PLIP device is always called ``plip0'', where first is
the first device detected by the system, similarly to what happens for
Ethernet devices. The actual parallel port being used is one of the
available ports, as shown in /proc/parport. For example, if you have
only one parallel port, you'll only have a directory called
/proc/parport/0.
</para>
<para>
If your kernel didn't detect the IRQ number used by your port,
``insmod plip'' will fail; in this case just write the right number to
/proc/parport/0/irq and reinvoke insmod.
</para>
<para>
Complete information about parallel port management is available in
the file Documentation/parport.txt, part of your kernel sources.
</para>
</sect1>

1736
LDP/guide/docbook/Linux-Networking/PPP-SLIP.xml
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File diff suppressed because it is too large Load Diff

33
LDP/guide/docbook/Linux-Networking/Sources.xml
View File

@ -1151,5 +1151,38 @@ who we should thank for writing the first versions of this document.
they wrote with questions but ended up giving me as much information
as I gave them. Unfortunately I haven't compiled a list of names
(maybe next time). You know who you are :-).
X Window System Architecture Overview HOWTO
Daniel Manrique
roadmr@entropia.com.mx 
Revision History
Revision 1.0.1 2001-05-22 Revised by: dm
Some grammatical corrections, pointed out by Bill Staehle
Revision 1.0 2001-05-20 Revised by: dm
Initial LDP release.
12. Copyright and License
Copyright (c) 2001 by Daniel Manrique
Permission is granted to copy, distribute and/or modify this document under
the terms of the GNU Free Documentation License, Version 1.1 or any later
version published by the Free Software Foundation with no Invariant Sections,
no Front-Cover Texts, and no Back-Cover Texts. A copy of the license can be
found [http://www.gnu.org/copyleft/fdl.html] here.
The LBX Mini-HOWTO
Paul D. Smith, psmith@baynetworks.com
v1.04, 11 December 1997
Leased line Mini HOWTO
The most recent (beta) version of this HOWTO can be found at:
http://www.sput.nl/software/leased-line/
1. Introduction
1.1. Copyright and License
This document is distributed under the terms of the GNU Free
Documentation License. You should have received a copy along with it.
If not, it is available from http://www.fsf.org/licenses/fdl.html.
</appendix>

358
LDP/guide/docbook/Linux-Networking/VNC.xml
View File

@ -258,364 +258,6 @@ my fault. Remember, what you do here could make very large holes in the
security model of your network. You've been warned.
-----------------------------------------------------------------------------
1.4.3. GNU Free Documentation License
Version 1.1, March 2000
Copyright (C) 2000 Free Software Foundation, Inc. 59 Temple Place, Suite
330, Boston, MA 02111-1307 USA Everyone is permitted to copy and
distribute verbatim copies of this license document, but changing it is
not allowed.
-----------------------------------------------------------------------------
1.4.4. PREAMBLE
The purpose of this License is to make a manual, textbook, or other written
document "free" in the sense of freedom: to assure everyone the effective
freedom to copy and redistribute it, with or without modifying it, either
commercially or noncommercially. Secondarily, this License preserves for the
author and publisher a way to get credit for their work, while not being
considered responsible for modifications made by others.
This License is a kind of "copyleft", which means that derivative works of
the document must themselves be free in the same sense. It complements the
GNU General Public License, which is a copyleft license designed for free
software.
We have designed this License in order to use it for manuals for free
software, because free software needs free documentation: a free program
should come with manuals providing the same freedoms that the software does.
But this License is not limited to software manuals; it can be used for any
textual work, regardless of subject matter or whether it is published as a
printed book. We recommend this License principally for works whose purpose
is instruction or reference.
-----------------------------------------------------------------------------
1.4.5. APPLICABILITY AND DEFINITIONS
This License applies to any manual or other work that contains a notice
placed by the copyright holder saying it can be distributed under the terms
of this License. The "Document", below, refers to any such manual or work.
Any member of the public is a licensee, and is addressed as "you".
A "Modified Version" of the Document means any work containing the Document
or a portion of it, either copied verbatim, or with modifications and/or
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A "Secondary Section" is a named appendix or a front-matter section of the
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The "Invariant Sections" are certain Secondary Sections whose titles are
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The "Cover Texts" are certain short passages of text that are listed, as
Front-Cover Texts or Back-Cover Texts, in the notice that says that the
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A "Transparent" copy of the Document means a machine-readable copy,
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Examples of suitable formats for Transparent copies include plain ASCII
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The "Title Page" means, for a printed book, the title page itself, plus such
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You may copy and distribute the Document in any medium, either commercially
or noncommercially, provided that this License, the copyright notices, and
the license notice saying this License applies to the Document are reproduced
in all copies, and that you add no other conditions whatsoever to those of
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If the required texts for either cover are too voluminous to fit legibly, you
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If you publish or distribute Opaque copies of the Document numbering more
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It is requested, but not required, that you contact the authors of the
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You may copy and distribute a Modified Version of the Document under the
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If the Modified Version includes new front-matter sections or appendices that
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You may extract a single document from such a collection, and distribute it
individually under this License, provided you insert a copy of this License
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1.4.11. AGGREGATION WITH INDEPENDENT WORKS
A compilation of the Document or its derivatives with other separate and
independent documents or works, in or on a volume of a storage or
distribution medium, does not as a whole count as a Modified Version of the
Document, provided no compilation copyright is claimed for the compilation.
Such a compilation is called an "aggregate", and this License does not apply
to the other self-contained works thus compiled with the Document, on account
of their being thus compiled, if they are not themselves derivative works of
the Document.
If the Cover Text requirement of section 3 is applicable to these copies of
the Document, then if the Document is less than one quarter of the entire
aggregate, the Document's Cover Texts may be placed on covers that surround
only the Document within the aggregate. Otherwise they must appear on covers
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1.4.12. TRANSLATION
Translation is considered a kind of modification, so you may distribute
translations of the Document under the terms of section 4. Replacing
Invariant Sections with translations requires special permission from their
copyright holders, but you may include translations of some or all Invariant
Sections in addition to the original versions of these Invariant Sections.
You may include a translation of this License provided that you also include
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between the translation and the original English version of this License, the
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1.4.13. TERMINATION
You may not copy, modify, sublicense, or distribute the Document except as
expressly provided for under this License. Any other attempt to copy, modify,
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1.4.14. FUTURE REVISIONS OF THIS LICENSE
The Free Software Foundation may publish new, revised versions of the GNU
Free Documentation License from time to time. Such new versions will be
similar in spirit to the present version, but may differ in detail to address
new problems or concerns. See [http://www.gnu.org/copyleft/] http://
www.gnu.org/copyleft/.
Each version of the License is given a distinguishing version number. If the
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1.4.15. How to use this License for your documents
To use this License in a document you have written, include a copy of the
License in the document and put the following copyright and license notices
just after the title page:
Copyright (c) YEAR YOUR NAME. Permission is granted to copy, distribute
and/or modify this document under the terms of the GNU Free Documentation
License, Version 1.1 or any later version published by the Free Software
Foundation; with the Invariant Sections being LIST THEIR TITLES, with the
Front-Cover Texts being LIST, and with the Back-Cover Texts being LIST. A
copy of the license is included in the section entitled "GNU Free
Documentation License".
If you have no Invariant Sections, write "with no Invariant Sections" instead
of saying which ones are invariant. If you have no Front-Cover Texts, write
"no Front-Cover Texts" instead of "Front-Cover Texts being LIST"; likewise
for Back-Cover Texts.
If your document contains nontrivial examples of program code, we recommend
releasing these examples in parallel under your choice of free software
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1.5. Document History
The original "VPN mini-HOWTO" was written by Arpad Magosanyi, <

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