lindberg@cs.chalmers.se (Gunnar Lindberg) (11/22/89)
At Chalmers University we run a campus Ethernet with address-
filtering bridges and several protocols (IP, DECnet, EtherTalk
etc). Now, some people want to connect a number of discless HP
systems to the network and before saying "yes" or "no" we need
to know a little more.
I think "HP discless" does not use IP, but instead something
proprietary (or possibly even something "standard") but our
local HP rep has not yet been able to tell. Therefore I'd
be very grateful if somebody (@hp.com ?) could supply some
info (or pointers to), e.g:
+ Brief overview of "HP discless" protocol: address formats,
Ethernet type fields, etc.
+ Expected behavior: expected amount of broadcasts and/or
multicasts and some indication of their usage.
+ Coordination needs: addresses, port numbers, names etc.
Thanks in advance,
Gunnar Lindberglaubach@hpiag0.IAG.HP.COM (Mark Laubach) (11/22/89)
Best as I can tell you at present is that the HP diskless protocol is a proprietary implmentation using link level access over an IEEE 802.3 network. It will work through bridges, it will not work through IP router gateways as the protocol is LLA. You probably want to cross post this in comp.sys.hp and see if you can get better answers to your queries. Regards, Mark Laubach HP
lindberg@cs.chalmers.se (Gunnar Lindberg) (11/30/89)
Many thanks to all of you who replied to my question - this net *is* an amazing source of information! A few days ago I got an answer from a HP employee who is responsible for the product and I'll make an attempt to summarize: >HP's discless protocol does not use IP. It uses a request/response >protocol at transport level. At link level, it is based on the >IEEE802.3 protocol. The design of this protocol was published in >1988 Oct Issue of HP Journal. Other people have also mentioned "Discless HP-UX Workstations" by Scott W. Wang, also from an HP journal - possibly it's the same piece of information. >The discless protocol will work on a single cable up to 500 feet or >cables connected by Lan bridge or Lan repeaters. It does not work >across IP gateways. > >HP's discless protocol is designed for kernel-to-kernel communication. >There is no user level interface. Conceptually, you can view it as >a bus protocol for multiple processors in which the bus is a IEEE802.3 >link. The layout seems to be: HP "extended SAP format", IEEE802.3 _______ ! ! ! ! 6 dst addr !_______! ! ! ! ! 6 src addr !_______! !_______! 2 length (instead of Ethernet2's "type") !___!___! 1+1 dstSAP, srcSAP (both = 0xfc = "ext SAP fmt") ! ! ! 1+3 control+padding !_______! !_______! 2 ext dstSAP (0x164f) !_______! 2 ext srcSAP (0x164f ?) ! ! . . . . 24 HP diskless protocol header . . !_______! . . . . data >Basically, there is a world-wide committee which controls the >protocol ID (SAP's). Every company is given a range of SAP's and >extended SAP's in which the company can develop its own protocol. >All IEEE802.3 Lan drivers are designed to recognize the protocol ID >and deliver the packets to the upper level service routine according >to protocol ID. If a system is not configured to serve a particular >type of protocol, then all packets for that packet are dumped. >Again, I would recommend you to put discless clusters in a subnet to >isolate lan traffic. In discless clusters, we use the network like a >I/O bus between the disk and processor. The traffic will be much >higher than the typical use of a network. The performance is pretty >good, the I/O rate through discless Lan is within 80% of local I/O. Once more: Many thanks for all replies, Gunnar Lindberg PS My question was explicitly about HP's implementation of "discless" but, as several people have pointed out, HP also has NFS, YP and the other TCP/IP stuff. DS