Date: 09 May 1999 21:14:10 -0400 From: chopps@merit.edu (Christian E. Hopps) To: "Louis A. Mamakos" <louie@TransSys.COM> Cc: freebsd-net@FreeBSD.ORG Subject: Re: osi layer Message-ID: <sy3r9oplo9p.fsf@scotch.merit.edu> In-Reply-To: "Louis A. Mamakos"'s message of "Sun, 09 May 1999 20:46:02 -0400" References: <sy33e15n70v.fsf@scotch.merit.edu> <199905100046.UAA66648@whizzo.transsys.com>
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"Louis A. Mamakos" <louie@TransSys.COM> writes: > > > > It would appear that FreeBSD removed the OSI code at some point > > in the past. > > > > I'm working on IP in IS-IS in GateD. For this to function I must > > have access to the OSI stack. I have it working under BSDI and > > NetBSD, but for obvious reasons it won't run under FreeBSD. > > > > IS-IS only needs a portion of the networking layer present > > and nothing above that. I need to be able to send packets on the > > Raw like OSI sockets (AF_ISO, SOCK_DGRAM, ISOPROTO_ESIS and > > ISOPROTO_CLTP). I do not need OSI routing to work. I don't > > actually need ES-IS (which is in kernel in BSD4.4) but if its not > > there I need some way to join the OSI physical layer multicast > > addresses. > > > > IP in IS-IS is actually fairly popular, so the removal of the OSI > > code may be worth reconsidering. > > Actually, it's not so much IP in IS-IS, but being able to run the > Integrated IS-IS interior routing protocol for the purposes of routing > IP traffic. To be clear, there's nothing different happening with the > encapsulation or carriage of any IP datagrams. > > For a variety of historic and interesting reasons, most major backbone > tier-1 backbone networks on the Internet use the Integrated IS-IS routing > protocol. When one IS-IS capable router exchanges routing protocol > messages with it's neighbor, the PDU's (packets for us Internet folk) > are not carried inside of IP, since they're not IP datagrams. Thus > the interest in physical layer ISO encapsulation to carry this traffic. Thanks for the resummary. I guess ``IP in IS-IS'' wasn't exactly clear; although, the concept of forwarding IP datagrams in IS-IS packets seems fairly weird :). I've been calling it IP in IS-IS becuase its short. Indeed IS-IS is an OSI routing protocol using OSI PDUs the IP routing information is stored in optional TLVs (type-length-values) and used in the routers to build the appropriate routing table (forward information base in OSI talk :) The protocol is very similar to OSPF but simpler. It is capable of doing both OSI and IP; however, my implementation will only support IP routing. In any case I believe very little OSI support is actually needed. The main things I'm using are the ISOPROTO_ESIS socket handling (i.e., handling sockaddr_dl destination addresses and 802.3 frame encapsulation) and the physical mcast joining. I may have forgotten something else in the kernel-code path, but I don't believe so. I've only heard one primary reason for the teir-1 networks using IS-IS, and yes I thought it was interesting. :) Thanks, Chris. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message
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