Date: Mon, 12 Apr 1999 14:51:41 +0200 (MET DST) From: Christoph Weber-Fahr <listmail@helena.callcenter.systemhaus.net> To: jimshewmaker@calvarychapel.com (Jim Shewmaker) Cc: Freebsd-isdn@freebsd.org Subject: Re: FreeBSD and ISDN Message-ID: <199904121251.OAA20175@helena.otelo-call.de> In-Reply-To: <199904082016.OAA19154@pearly.csn.calvarychapel.com> from Jim Shewmaker at "Apr 8, 99 03:05:32 pm"
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Hi > Any thoughts on my situation would be greatly appreciated. > > I am planning on using FreeBSD and ISDN for our Internet > gateway. I currently have a 2.2.8 Box with a V.90 modem in it. I > plan on using FreeBSD 3.1-Release on a different 486-100 with 16 > MB RAM and only a 540 MB hard drive. i Hm... depending on the functions you would like to implement, you might consider getting more drivespace. 540MB, while theoretically sufficient, may well get you in trouble with some runaway mail or web proxy. > I already have been given > an Adtran TA. I have never used ISDN for internet before. I plan on > using USWest's BRI plan that is geared to support the 2 B > channels, but more than 2 should work according to their tech > support. This is most definitely wrong. They would have to redefine the BRI interface to make this happen. BRI (=Basic Rate Interface) consists of two B and one D channel. > I also would like to just use the asynch ports on the > motherboard unless somebody has good reasons why I shouldn't. > I wouldn't mind using a nice synch, but if I can postpone it until my > next budget, I will. This entirely depends on your TA (with which I'm not familiar). Typically your TA will present a kind of Modem Interface towards the PC, so you have to use an async connection anyway. On the other hand, if you want your TA to aggregate two channels doing Multilink-PPP (I've heard of some TAs capable of that), you will need a Link capable of handling the aggregate 128 kbps data rate. Most 'built in' 16550 compatible async can't do that. > Here is a twist: We need the ISDN for a live audio feed that we > rebroadcast. Since you deal in B Channmles here I assume this is directly ISDN based and not bound to any IP family protocol. > Currently it is once or twice a day for about 1.5 > hours, with special day long events four times a year. The smaller > shows only need mono (one B channel), but I have to give up both > channels on the special events. Hm... Putting more than one device onto an ISDN S0 bus is not a problem, but you have to have an ISDN bus for that. If I remember correctly you like to play with uk0 over there , so again, consult your TA's manual as well as the documentation of your carrier. A correct solution would be an ISDN connection, an NT, and then the TA and your Audio Equipment both on the S0 bus. > I am looking into using more than two B channels so that we can > still have our web and email servers available to the rest of the > Internet. This is not possible with one BRI line. If you have more than one line, you will get into trouble with those 'I can convert sync-multilink-to- async-ppp TAs, since I douibt you can again combine them into a larger MPPP bundle). I sincerely recommend you buy a real ISDN router in this case. > It would also be great if I can keep the multilink dynamic > enough to automatically adjust between using 1 to 4 channels so > that the audio people are unaffected, as well as somebody > downloading a file. I doubt this would work with the TA, but again, check the TA's docs. > Anyway, since I am looking at doing this as a semi-dedicated > line, is there anything I need to worry about accept for making my > idle timeouts huge? > > Another minor consideration is that in the future they plan on > serving real audio on this web server via this ISDN to the listeners > on the Internet. Any thoughts and all comments would be greatly > appreciated, might as well do this right the first time. You want to serve real audio over IP to customers ?? Well, - get a dedicated T1 link. - buy a real router (for a T1 link, you might even get away less costly than with two BRI interfaces). Regards Christoph Weber-Fahr To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-isdn" in the body of the message
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