I've done some more investigation. The protocol is an ICL (a brand now subsumed into Fujitsu) protocol called OSLAN (try a Google search on OSLAN protocol). OSLAN is, as Dave was describing, TP4 over 802.3; I don't know about the null CLNP stuff.
OSLAN is in widespread use in the UK - wherever there is an ICL mainframe. This tends to be government organisations or organisations with a government legacy, like ourselves. I've attached a capture of some sample activity. The capture starts with four connections disconnecting, then the four reconnecting, then a test message down the connection, then all four connections closing again. We'd love to have this working in Ethereal. Many thanks, Matthew -----Original Message----- From: Guy Harris [mailto:[EMAIL PROTECTED] Sent: 22 May 2003 23:11 To: Dave Piscitello Cc: CNS - Matthew Bradley; 'ethereal-usersetherealcom' Subject: Re: [Ethereal-users] ISO8073 OSI COTP over Ethernet On Thu, May 22, 2003 at 05:25:07PM -0400, Dave Piscitello wrote: > I worked on the IEEE and ISO committees that created the LLC/SNAP > headache/header, nearly 20 years ago, and no standard I know specifies this. > > I have this fuzzy recollection of a "version" of CLNP called "null", where > there's no CLNP header, only the single, initial protocol identifier with a > value of zero. Yes, there is - it's the "inactive subset" of CLNP. > If every host you ever wanted to have communicate is connected to an 802.3 > network, you could in theory use MAC addressing and framing(the network > layer in this situation doesn't provide any added function), then > encapsulate TP4 in a null CLNP (one octet of zero), and then indicate it's > CLNP in the LLC SAP value Guy mentions, in the 802.3 frame. We already handle the inactive subset of CLNP, and dissect the stuff after the inactive subset as COTP, so that's presumably not what he's seeing on his network. CNS 4 Brunel Way, Fareham, PO15 5TX Switchboard : +44 (0)1489 589922 Fax : +44 (0)1489 554100 Help Desk : +44 (0)1489 581234 http://www.cnsonline.net/ Reg. no. 2084279 England ************************************************************* All views or opinions expressed herein are solely those of the author and do not necessarily represent those of Community Network Services Ltd who do not accept liability for any action taken in reliance on the contents of this message (other than where the company has a legal or regulatory obligation to do so) or for the consequences of any computer viruses which may have been transmitted by this E-Mail The E-Mail and any files transmitted with it, are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this message in error please notify the sender and delete the message immediately or alternatively email [EMAIL PROTECTED] ***************************************************************
sample-oslan2.pcap
Description: Binary data
