Is NetBIOS a protocol in the sense of ISO's OSI definition?? I never really checked it. Originally it was a programming interface on IBM PCs. I did some network programming with NetBIOS back in 1989... yes, old man...
When I started reading commercial Cisco certification books, the authors sometimes tried to convince me that it is a protocol....Whatever, I'm not going to give a formal answer, but for those interested maybe give the following a try. It's from IBM's TCP/IP Tutorial and Technical Overview, October 1998, one of their famous redbooks (http://www.redbooks.ibm.com): "... NetBIOS is a vendor-independant software interface (API), not a protocol. There is no official NetBIOS specification, although in practice, the NetBIOS version described in the IBM publication SC30-3587 LAN Technical Reference: 802.2 and NetBIOS APIs is used as reference. .." Have fun! :-) Eric Brouwers ----- Original Message ----- From: "Priscilla Oppenheimer" To: Sent: Tuesday, June 24, 2003 3:50 AM Subject: Re: netbios [7:71084] > - jvd wrote: > > > > OT: > > hi, i just have to say that i will never try to answer anything > > on this forum again. :-) > > Well, would that be Grumpy, Bashful, Sleepy, or Dopey to do that? :-) > Seriously, you should keep answering. You have sent some great answers, but > you don't want to keep insisting something when replying to my messages. It > makes me very Grumpy and I'm not Bashful when wielding a keyboard (just in > person). I know lots of books claim that NetBIOS isn't routable, but I bet > those exact same books also classify it as a session-layer protocol. And it > does make a good example of a session-layer protocol. One of the few that we > have! And if it runs at that layer, then it is routable. I think even IBM > said it was a session-layer protocol in some of their early documents, which > unfortunately, I recently tossed. > > Directed broadcasts came from out of the blue. I really don't think Windows > networking uses them, although maybe it does. Was the comment maybe in > reference to the helper address suggestion that I made? You can tell a > router to send the packets when "it helps" as a broadcast. That's not a > directed broadcast, though, and will work even if router forwarding of > directed broadcasts is disabled, which is the default these days. Instead, > it's a broadcast sent by the router (it has the router's IP address as > source, on behalf of some other station, to a local LAN, because the router > is acting as a proxy, for example, a DHCP Relay Agent.) Was that a run-on > sentence, or what? :-) > > A directed broadcast is directed from afar into a subnet. The sender usually > makes classful assumptions, since it can't actually know the local > definition of a broadcast. It's used by ping scan to send a ping to > 172.16.255.255, for example, in an attempt to ping everyone on network > 172.16.0.0. Routers don't forward those these days because of the security > risks. > > Back to NetBIOS. It does send a lot of broadcast traffic for naming > purposes. In an IP environment, however, a host can be configured to send > unicast naming queries and name registrations to a WINS server. There are > probably lots of other issues, though. It really can be quite a pain to get > it to work correctly when you migrate from a small LAN to a larger > internetwork with WANs, subnetting, VLANs, etc. > > > I wonder what the original poster is really trying to do and where he can > get a good Windows networking (internetworking) design guide. Cisco used to > have one, but it's probably way dated now.... > > > Well, it's late and my writing is deteriorating. Howard covers directed > broadcasts, by the way, (and a much better description of the OSI model, > without reference to the dwarves, as I recall, although possibly with > reference to the deadly sins) in his CertificationZone papers. I recommend > them. > > Priscilla > > > > > > once i tried to answer a question with regards to bgp and a > > 1720 router and only after howard helped us out was it clear > > that the processor does play an important role. ;-) > > > > this time only after the input from priscilla is everybody > > happy about the netbios/netbeui issue. ;-) > > > > but then i think what is important is that we dig a bit deeper > > into some topics! > > > > Good work! Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=71231&t=71084 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
