Hi It would appear we are saying the same thing. It looks like I got reasonably close and you are confiming that I'll also take it that my interpretation of the relative positions in the OSI model etc. are OK. You imply this anyway. Would you mind answering one or two DECnet questions? Regards Rod -----Original Message----- From: cctech-bounces at classiccmp.org [mailto:cctech-bounces at classiccmp.org] On Behalf Of dave at mitton.com Sent: 06 June 2007 00:30 To: cctech at classiccmp.org Subject: Re: DECnet and MOP org... >I probably failed to make my self clear. > > 1. Yes MOP is part of a whole heap of programs that go to make up > DECNET > 2. MOP stands for Maintenance Operations Protocol and that > what is was for. > 3 It pre dates DECnet (Well at lest internally in DEC) MOP is part of the DECnet architecture set, and like DECnet has gone through a number of versions, and releases. It actually underwent a boom in the later years, as Ethernet got cheap and diskless network devices became attractive. It is a simple lower level datagram protocol, and does not need the normal session stack to run. In smarter network devices, a MOP bootstrap can be in the device ROM. All that said; architecture, implementation, and deployment vary with platforms and time. For those that grew up on TCP/IP only (and thus doomed to repeat the past), it is best to think of MOP as the DECnet analog of BOOTP, with a little bit of DHCP and ARP sprinkled in. ... There's your problem. I was a software engineer for DECnet-RSX, DECnet-PRO, DECnet-DOS, and PATHWorks. I was also the architect of the DAP Protocol v6 and a DECnet Token Ring Datalink. The later included MOP specfications too. I still have copies of all the Phase IV era DNA specs. Dave.