Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!uwm.edu!zaphod.mps.ohio-state.edu!usc!ucsd!ucsdhub!hp-sdd!hplabs!hp-ses!hpbbn!hpbbi4!markl
From: markl@hpbbi4.HP.COM (#Mark Lufkin)
Newsgroups: comp.sys.hp
Subject: Re: Booting discless over multiple LANs
Message-ID: <1720001@hpbbi4.HP.COM>
Date: 1 Feb 90 17:39:33 GMT
References: <3249@plains.UUCP>
Organization: Hewlett-Packard GmbH
Lines: 35

> I had everything correctly connected, and then tried to add the discless
> machine using reconfig.  I entered the proper Link Level Address, gave it
> an Internet address corresponding to the proper LAN card and waited.  
> Unfortunately it didn't boot.  Here's the reason:  In the system admin
> manual, while following the flowcharts in the trouble shooting section,
> it said that *** the remote boot daemon can only run on one LAN ***.
> I then confirmed this with Response Center.  This means I can't boot
> the machine in the other building as a discless cnode.
> 
> My question:  Has anyone managed to get around this?  Is there patches
> to the rbootd code to allow more than one LAN?  My present solution is
> to take a 55 Meg Tape/Disk drive with barebones HP-UX 6.21 up to the 
> remote machine and make it standalone.  This causes me to sysadmin two
> machines instead of one along with some possible software licensing
> problems.  My other alternatives all involve even uglier situations
> (extending lan0 to other building, remote boot off other depts. hp's on
> the lan, making it a full system{$$}).

	This is a well known feature of the HPUX diskless. The point is that
	when your system boots, it does a broadcast. If there happens to be
	a gateway or router or whatever between your two LANs then the
	message will not be passed across. The reason for implementing
	the boot procedure in this way is to make the system be able to 
	recover from network errors -  a diskless system is able to check the
	LAN if it has a failure. If it detects that the LAN is broken then
	the client will wait indefinitely for the LAN to be fixed and the
	server to respond. Another point is that it is not a ggod idea to
	boot across the backbone LAN as this will cause performance problems -
	swapping on the LAN, filesystem transfers and broadcasts (well, 
	multicasts really).

Mark Lufkin
EMC/CPS OS Technical Support
HP/Apollo Boeblingen
West Germany.