Date: Tue, 29 Feb 2000 13:31:40 -0500 From: Dennis <dennis@etinc.com> To: Joe Abley <jabley@patho.gen.nz>, Eddie - EAZNet Internet Services <eddie@eaznet.com> Cc: FreeBSD ISP Mailing List <freebsd-isp@FreeBSD.ORG> Subject: Re: ATM DS3 Message-ID: <200002291832.NAA29072@etinc.com> In-Reply-To: <20000301042744.B24877@patho.gen.nz> References: <38BABA13.2CFAA57A@eaznet.com> <38BABA13.2CFAA57A@eaznet.com>
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At 04:27 AM 3/1/00 +1300, Joe Abley wrote: >On Mon, Feb 28, 2000 at 11:10:27AM -0700, Eddie - EAZNet Internet Services wrote: >> Is there a way to use a FreeBSD box to handle a 6MB DS3 over ATM? It >> wouldn't even have to do routing or anything. Just be able to break out >> the channel and feed it into a routers HSSI port. > >The packets that arrive over your ATM PVC will be (probably) AAL5-framed, >possibly with a SNAP header. You're unlikely to use this encapsulation >over your HSSI interface (you're probably using cisco hdlc or ppp). > >So, unless you're planning some funky excursion into cells-in-frames, >you're going to have to re-encapsulate -- which means you probably want >to route. > >There is ATM support in FreeBSD, and I presume it handles PVCs if it >does anything. Your questions really are, I think: > > + does anybody sell a DS3 ATM adapter which is supported by FreeBSD? > > + does anybody sell a HSSI adapter which is supported by FreeBSD? We have HSSI adapters, but you cant do ATM over HSSI because there is no cell deliniation information available. HSSI is typically HDLC protocols and ATM is not HDLC. The only way to use a HSSI for DS3 ATM is to use a convertor..typically the convertor translates ATM to Frame Relay and you run frame relay over the hssi. This, in fact, is what most providers do to provide frame relay DSL services which have a native ATM backbone. The last time I checked it was about $11,000. for a 1 port convertor, so you're looking at $15K or so for a freebsd solution with the convertor. It may be less now....Kentrox has one and GDC does (i think also)...but I've never priced that one. Of course you dont need a CSU/DSU with this solution, so you save $3000. there on a straight hssi. >I take it those are US$. Cisco ATM port adapters seem hideously expensive. >Just another good reason to avoid ATM, I suppose :) Yes, ATM sucks (plus you'll only get about 32M on a T3 usable bandwidth (vs 41M on a cisco hdlc hssi or frame relay line), but the telcos want it so you're stuck with it. Dennis To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-isp" in the body of the message
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