scanner@pawl.rpi.edu (Eric "Scanner" Luce) (01/21/89)
Is it at all possible for a Mac Plus to change its appletalk node number WHILE the machine is turned on? (ie: no reset, no reboot, no power off?) Or, what would happen if a Mac was temporarily disconnected from the LocalTalk and then re-connected? Would it retain it's old node number? What if someone else claimed a node number when the mac was disconnected? Any comments would be appreciated. E-mail or otherwise, tnx in advance! --Scanner -- internet: scanner@itsgw.rpi.edu -- bitnet: userf0f3@rpitsmts.bitnet
RSILVERMAN@EAGLE.WESLEYAN.EDU (Richard Silverman) (01/21/89)
Scanner,
When the Mac boots, it attempts to open the ATP drivers. If it's
connected to an AppleTalk network, it will pick a node number and use a LAP
control packet to determine whether it is unique (other nodes will respond
if it is not). It then stores that node ID in parameter RAM, and uses it
as the first node ID to try the next time the drivers open. This way, node
IDs tend to remain stable. The only way it should change while it's still
on is if the ATP drivers are closed and then reopened, and in the mean time
someone else (presumable a device brand new to this network) has been connected
and claimed that ID -- unlikely situation. Of course, if you have a device
that's misbehaving by not reusing it's old node ID, or perhaps not obeying
the LAP control protocol, then you could have problems.
Richard Silverman
arpa: rsilverman@eagle.wesleyan.edu Wesleyan University
bitnet: rsilverman@wesleyan Middletown, CT
CIS: [72727,453] 06457jeff@drexel.UUCP (Jeff White) (01/22/89)
In article <245@rpi.edu>, scanner@pawl.rpi.edu (Eric "Scanner" Luce) writes: > Is it at all possible for a Mac Plus to change its appletalk node > number WHILE the machine is turned on? (ie: no reset, no reboot, > no power off?) > > Or, what would happen if a Mac was temporarily disconnected from > the LocalTalk and then re-connected? Would it retain it's old node > number? What if someone else claimed a node number when the mac > was disconnected? My impression was that each time the Mac was on Appletalk (either powered on to an already connected network, or when the AppleTalk was turned on in the Chooser), it sent out a broadcast message announcing it on the net with it's number. I assume the first time it connected, that number might be random. If there was another station with that number, this Mac would hear a response and be forced to choose another number. This would go on until a unique id was found. That number would then be saved in the PRAM. The next time the Mac was turned on, this number would be tried first. In most cases, the network doesn't change, so there shouldn't be any conflict, and the time wasted by trial and error is eliminated. If a new station is added, then the process is just gone through again. Jeff White Drexel University - ECE Dept. rutgers!bpa!drexel!jeff
urlichs@smurf.ira.uka.de (Matthias Urlichs) (01/24/89)
In comp.protocols.appletalk scanner@pawl.rpi.edu (Eric "Scanner" Luce) writes:
< Is it at all possible for a Mac Plus to change its appletalk node
< number WHILE the machine is turned on? (ie: no reset, no reboot,
< no power off?)
Yes it is.
Open the Chooser, turn off AppleTalk, turn it back on.
The Mac will then look for a free node number which of course isn't
necessarily the same as the old one.
<
< Or, what would happen if a Mac was temporarily disconnected from
< the LocalTalk and then re-connected? Would it retain it's old node
< number?
Yes it would. Pulling the AppleTalk plug is just like as if nothing
happened on the network for a while. (Assuming you don't try to print
to your LaserWriter right now :-) )
< What if someone else claimed a node number when the mac
< was disconnected?
You would run into serious problems. Don't do that.
Always turn AppleTalk off in the Chooser before plugging AppleTalk
into a Mac. (Since the LaserWriter has no Chooser, you should turn the
printer off before plugging in the AppleTalk connector.)
Disclaimer: I really don~t know anything, as should be obvious from this posting.
--
Matthias Urlichs -- Humboldtstrasse 7 -- 7500 Karlsruhe 1 -- FRG
urlichs@smurf.ira.uka.de -- ++49+721-621127@PTTshibumi@well.UUCP (Kenton A. Hoover) (02/02/89)
In article <872@drexel.UUCP> jeff@drexel.UUCP (Jeff White) writes: >In article <245@rpi.edu>, scanner@pawl.rpi.edu (Eric "Scanner" Luce) writes: >> Is it at all possible for a Mac Plus to change its appletalk node >> number WHILE the machine is turned on? (ie: no reset, no reboot, ... >> was disconnected? > My impression was that each time the Mac was on Appletalk (either powered ... >then the process is just gone through again. It does, when the machine boots and ALAP is opened, send out a packet saying "I'm here and does anyone object to this node number. However, on the Mac we are using as an appletalk test drone, the node number seems to change quite frequently -- on both an SE and a II. We have no explanation for this, but its an interesting effect. I think that you could change the net number while the machine is running by closing all of the appletalk drivers, and changing the last node number global stored in the pram. When you reopen the driver, it is supposed to use that number. If you choose a number in the server range and open the driver normally though, it wont let you have a server node number irregardless. -- ! Kenton A. Hoover {hplabs,apple,pacbell}!well!shibumi ! ! Phoenix Project Manager SNAIL: One Bush Street ! ! Hambrecht & Quist San Francisco, CA 94105 ! ! "Evil will always triumph over good because good is dumb!" !