Date: Tue, 31 Mar 1998 11:12:12 -0600 (CST) From: Tim Salo <salo@networkcs.com> To: reddawg@shellz.malicia.com Cc: freebsd-atm@FreeBSD.ORG Subject: Re: OC3 Message-ID: <199803311712.LAA07876@us.networkcs.com>
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> Date: Thu, 26 Mar 1998 16:20:14 -0500 (EST) > From: Christopher <reddawg@shellz.malicia.com> > To: Mark Tinguely <tinguely@plains.NoDak.edu> > cc: freebsd-atm@FreeBSD.ORG > Subject: Re: OC3 > > Im not sure im new to atm i do know on the other end will be a cisco and > im not sure what that would use over the atm. > > > > How would i go about making a freebsd box into an oc3 router that would > > > take place of a cisco? You, in some sense, need to ensure that both devices agree on what protocol to use at each layer in the protocol stack. Perhaps, o ATM: PVCs or SVCs, UNI 3.0/3.1 SVCs versus (maybe/unlikely) UNI 4.0 o AAL: AAL5 is typical, but at least one ATM DSU uses only AAL3/4, (don't use that ADSU...) o Encapsulation: LLC/SNAP is typical, but sometimes null encapsulation is used. Some odd devices, perhaps some ADSUs, might use NLPID encapsulation. (FR/ATM interworking devices might use NLPID; I don't know, I have never seen one.) See RFC 1483. o IP/ATM Convergence Sublayer (does this stuff have name): The two major choices are IETF Classical IP (RFC 1577) and ATM Forum LANE (LAN emulation). The two standards (or, is that "standards"?) don't interoperate. Some software supports one but not the other. This is probably the most important protocol choice to ensure that you get right. o IP/ATM Short-Cut Sublayer (I am pretty sure this doesn't have a name.) The IETF says NHRP while the ATM Forum says MPOA. This shouldn't be an issue for you; I included it just for the sake of completeness. (The IETF and the ATM Forum say MPOA and NHRP interoperate. I wonder if anyone has tried.) If you get this far, your higher layers should be no problem. I believe that you will be (far) better off if the Cisco router on the other end has a native ATM interface (e.g., an AIP card) rather than a HSSI interface with an external ATM DSU. (Details available on request, I suppose. Someday I should finish writing the whole story...) -tjs To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-atm" in the body of the message
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