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Question on ATM w/ FreeBSD



On Sat, 4 Sep 2004, Ted Mittelstaedt wrote:

TM>> If your card does not support VPI 1, you need a small ATM switch to move
TM>> ATM PVCs from one VPI to another. Fore ASX-200BX is excellent small and
TM>> cheap switch.
TM>>
TM>
TM>Are any of the cards mentioned - Fore LE155, PCA-200, HE155, not support
TM>VCI 1?
   ^^^ VPI probably?

The HE155 has a configurable VPI/VCI space of 12 bits that you can split
between VPI and VCI. Per default the driver uses 2 VPI bits and 10 VCI bits.

The PCA-200 definitely can do only VPI 0.

For the LE155 I don't remember.

harti

TM>> > My suspicion is that it's going to end up being Routed.  The reason why
TM>> > is that we are already using a different group within this carrier to
TM>> > provide Frame Relay to customers -ie: we buy Frame circuits from their
TM>> > network to supply bandwidth to customers.  Basically it's ATM vc's from
TM>> > us to their ATM switch which interworks it to a Frame circuit that the
TM>> > end user sees on the usual T1.  That is of course a completely separate
TM>> > DS3 than what we are looking at buying.  But the circuits provisioned
TM>> > off that are Routed not bridged, and all5snap, and vbr.
TM>> >
TM>> > It would also almost certainly be a single VC on the DS3.
TM>> >
TM>> > DSL egress in this market, by contrast, is all Bridged, both
TM>> with Verizon
TM>> > and Qwest.  (we have both those ilecs here, ugh)  They both use vbr and
TM>> > aal5mux.
TM>> >
TM>> > I have another question for you guys,- if I am using routed/vbr
TM>> is there any
TM>> > benefit to using a forerunner he155 and the fatm() driver as opposed to
TM>> > a Fore LE155 with the idt() driver?  Also, what exactly is the
TM>> difference
TM>> > between a Fore LE155 and a Fore PCA-200 (which uses the hfa() driver I
TM>> > understand)?
TM>> >
TM>> > You are right in there being no cheap IDT77252 cards out there.  I don't
TM>> > have $2-3K on this project to throw into atm pci cards. :-(
TM>> No real need to get HE vs LE. I am doing all of this on linux on LE
TM>> card...
TM>>
TM>> > Has anyone worked with the Ascend/Lucent/Avaya PSAX gear, like the PSAX
TM>> > 100? Is that an ATM switch that could run a VC from one interface to
TM>> > another? The documentation on Avaya's site is very unclear plus the PSAX
TM>> > 100 has been long discontinued.  But because of that they appear to be
TM>> > rediculously cheap on the secondary market.
TM>> Like I said, take ASX200BX - it is still supported.
TM>>
TM>
TM>The switch chassis themselves are cheap enough on Ebay.  But where you run
TM>into trouble is the DS3 cards for them usually aren't included with the
TM>switches, and are a lot harder to find secondhand.  Not impossible, though,
TM>but rarer.
TM>
TM>And I don't much care about the supported/unsupported aspect of the
TM>equipment
TM>I use anyway.  I'm the first line of support here.  And the user community
TM>like the mailing list here, is the second line.  And it doesen't make a
TM>lot of sense to spend $2K a year on a support contract with Cisco for a
TM>used 7206 that you bought off Ebay.  For starters you don't get hardware
TM>support anyway, and secondly, I've used Cisco support enough times in the
TM>past to know that they aren't much good for the truly knotty problems.  If
TM>we are buying used Fore switches/atm cards/ etc. I am not expecting any more
TM>support than a copy of the user manual.  Remember this is all going into
TM>a FreeBSD router that will be running BGP, so I'm already on my own for
TM>support there, anyway.
TM>
TM>The Lucent PSAX gear I've seen on the secondary market, some of it is
TM>going for under $100.  Compared to a used Fore ASX200BX at $800+, to me that
TM>is worth screwing with it - that is, if anyone can possibly confirm that
TM>the PSAX even is an ATM switch.
TM>
TM>Call Cisco support sometime and ask them why your 7206 running 12.0.7T
TM>IOS reboots about once a month or so.  That's support for you.
TM>
TM>Ted
TM>
TM>> >
TM>> -alex
TM>>
TM>>
TM>
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TM>
TM>