Path: utzoo!attcan!uunet!seismo!sundc!pitstop!sun!decwrl!labrea!agate!saturn!eshop From: eshop@saturn.ucsc.edu (Jim Warner) Newsgroups: comp.protocols.appletalk Subject: Re: AppleTalk across Internet? Message-ID: <4986@saturn.ucsc.edu> Date: 2 Oct 88 07:38:17 GMT References: <8809290142.AA26741@columbia.edu> Reply-To: eshop@saturn.ucsc.edu (Jim Warner) Organization: University of California, Santa Cruz Lines: 21 In article morgan@JESSICA.STANFORD.EDU writes: > > >Hmm, I always thought the MTU of the ARPANet was 1008. I wonder what >the MTUs of the NSFNet and the various regionals are? > The MTU (Maximum Transmission Unit) of your regional network (BARRNet) and the NSFNet is the Ethernet maximum. I can't speak for the other regionals, but I would be very suprised if their MTU was any less. This is fairly easy to test; Berkeley unix ping has an option that allows you to specify the size of the ICMP echo request packet up to ~2000 bytes (guaranteed to fragment on an Ethernet). You need an Ether-scope or 'tcpdump' on a Sun to see if what comes back has been fragmented. You may want to contact your campus networking services office to verify which remote sites are accessed over NSFNet. It is not always easy to tell. --jim