CAP/man/UAB.8

.TH uab 8
.SH NAME
uab
\- Unix AppleTalk Bridge
.SH SYNTAX
.I uab
-D <level>
-f <bridge_description>
-l <log file>
-d
tdump debug nodebug statistics (stat) exit
.SH DESCRIPTION
The Unix AppleTalk
Bridge (
.I uab)
program allows certain unix systems to act as AppleTalk
Bridges.  
.I uab
can be functionally divided into two parts.  The
first is the actual AppleTalk Bridge implementation and the second are
the routines that define particular "Link Access Protocols" (aka
"hardware" delivery methods e.g. EtherTalk).  
.I uab
also supports an
internal demultiplexing that allows
packets delivered to the 
.I uab
node to be delivered to other processes
within that system.  
.PP
Currently, 
.I uab
runs on Ultrix 1.2 (and beyond) and SunOS 4.0 and
supports EtherTalk (Phase 1). Unfortunately, with the current definition of
KIP's UDP encapsulation and delivery rules, it is not feasible to
implement KIP.
The only internal packet
delivery mechanism defined is a modified version of KIP's UDP
encapsulation (modified-KIP) that uses a different UDP port range over
the internal
loopback; thus CAP programs must be relinked with a different low
level delivery mechanism to work with 
.I uab.
Note that all packets for
these programs are sent and received through the 
.I uab process.
.PP
Since 
.I uab
does not understand KIP, 
it is necessary to have an AppleTalk Bridge that
understands both KIP encapsulation and EtherTalk before KIP based
"systems" (e.g. programs compiled with CAP, bridges that only speak
KIP on the ethernet interface--revisions of KIP before 2/88, etc) can
work with 
.I uab's
modified-KIP based programs.
.PP
uab is configured by use of a "bridge description" file described in
detail later.
.PP
The flags are: D to set the debugging level to a particular value, d
to increment the debug level by one, f to specify a bridge description
file (default bridge_desc), and l to specify a logging file (default none).
.I uab
acts in response to certain signals.
.I uab
invoked as:
.nf
	uab <name>
.fi
where name is one of tdump (SIGUSR1), debug (SIGIOT), nodebug
(SIGEMT), statistics (SIGUSR2), or exit (SIGTERM) will
send these signals.
tdump causes the running uab to dump its internal tables (rtmp, etc.) to
/usr/tmp/uab.dump.  (dump is
reserved for nbp if uab ever support nbp).  debug tells the running
uab to increment the debug level: if not log file was currently
active, the log will go to /usr/tmp/uab.run.
nodebug turns off all debugging.
stat or statisitics dumps statistics to /usr/tmp/uab.stats.  exit
causes the running uab to stop.
.PP
The bridge description file is a list of the valid ports for a
particular Unix AppleTalk Bridge (UAB).
In order to minimize the maintaince headache, one may use the host
name as a selector.
Each port description is entered on a single line.
.PP
The first item in a line is the host selector field.  It can be the
host name (as returned by gethostname).  In addition, you can use % to
match any character.  "*" can be used to match any host.  Finally, you
can use "*" at the end of a string to complete a match.  (Allowing "*"
at both the beginning and end or at an arbritrary location is a pain
because it is an unanchored search -- would have to use a regular
expression matcher to do this -- ugh).
.PP
The second field contains a tuple that specifies the interface's
link access protocol (LAP) and any device specific data required.
Valid LAP method specifications:
.nf
    ELAP - EtherTalk Link Access Protocol 
    EtherTalk - same as above
    ASYNC - Asynchronous AppleTalk
    ASYNCATALK - same as above
.fi
The device specific data consists of a "device name" followed by an
colon and a "device number".  If the colon is omitted, the device
number is assumed to be zero.
For Ethertalk, this should be interpreted as a ethernet "tap" device
(SunOS, Ultrix).  For example, "ie:1" for ethertalk on interface ie1.
For Asynchronous AppleTalk, this is just a label. Suggested use as:0
.PP
The third field specifies the local demultiplexing delivery
mechanism for delivery of DDP packets not destined for the bridge
process.  Currently defined mechanisms are: "none" which says there
will be no other client processes; "mkip" - modified version of kip
style udp encapsulation using a different udp port range.
Specify 'none' for Asynchronous AppleTalk.
(Hopefully, there will be a way to do direct kip etc. in the future)
.PP
The fourth and last field specifies two items paired in a
[<item1>,<item2>] format.  The first is the DDP network that should
be associated with this port.  If you specify zero, the ddp network
number will be acquired via RTMP if there are other bridges that
know the network number.  Note that only a single network is allowed
at this point.  The network number may be specified as <number> or
<high byte>.<low byte>.  In both cases, the number may be decimal
(no leading zero), octal (leading zero), or hexadecimal (leading 0x
or 0X).  If this field is not specified,
.I uab
will assume that this port is for multiplexing only.  It will not send
out any rtmp data packets or respond to rtmp network request packets, etc.
.PP
The second item specifies the zone name associated with
the ddp network associated with this port.  If it is not specified,
it will be acquired via ZIP if there are other bridges on the
network that know the zone name.  Note: you may omit the comma if
you do not wish to specify a zone.
Note, \ can be used to quote a character (like a space in the zone
name :-)  A "\" at the end of a line continues the line.  Carriage
return and line feed both terminate a line.
.PP
You MUST SPECIFY a network number and Zone for Asynchronous AppleTalk.
.PP
You should order the file from more specific to less specific (in
terms of host name matches.  Once a match has been found, then only
matches with the exactly same pattern will succeed!
.SH BUGS
None known.
.SH NOTES
Better method for internal demuxing is needed.
.SH AUTHOR
Charlie C. Kim, Academic Computing and Communications Group, Center
for Computing Activities, Columbia University
.SH FILES
.nf
/usr/tmp/uab.stats
/usr/tmp/uab.run
/usr/tmp/uab.dump
.fi