Date: Fri, 07 Jul 1995 17:41:57 -0700 From: "Amancio Hasty Jr." <hasty@rah.star-gate.com> To: Bill Fenner <fenner@parc.xerox.com> Cc: hackers@freebsd.org Subject: Re: current SOTA in ISDN support? Message-ID: <199507080041.RAA00217@rah.star-gate.com> In-Reply-To: Your message of "Fri, 07 Jul 1995 09:37:58 PDT." <95Jul7.093807pdt.49860@crevenia.parc.xerox.com>
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>>> Bill Fenner said:
> In message <199507070351.UAA00815@rah.star-gate.com> you write:
> >o voice communication with vat point to point since the MBONE is
> > not quite upto ip multicasting yet due to old routers or tcp/ip routing
> > software still being used. And hopefully in the not too distant
> > future teleconferencing.
>
> That's odd, I use the MBONE over my ISDN line almost every day, and I have
> successfully participated in teleconferences over my ISDN line (getting poor
> quality video, but perfect audio).
>
> Bill
Hi Bill ,
The quality of service provided that there is a enough bandwith depends
on whether there are any routers on your path with old routing software.
>From the horses mouth :
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To: Saku Setala <setala@mits.mdata.fi>
Cc: mbone@ISI.EDU
Subject: Re: Packet duplication on NASA session
In-Reply-To: Your message of Sun, 02 Jul 95 14:09:57 JDT.
Date: Mon, 03 Jul 95 07:44:09 PDT
From: Van Jacobson <van@ee.lbl.gov>
> Currently, my nv reports ~ 200kbps on Nasa session, with up to
> ~ -45% loss.
>
> Pretty strange, huh?
I wish it were unusual. Ever since cisco's PIM got widely
deployed, the number of duplicate packets on the MBone has
skyrocketed & a 45% dup rate is actually lower than normal.
I find that almost all the traffic coming from Europe & the UK
is duplicated at least once.
The duplicates you're seeing are probably due to either
- A PIM cloud hooked to the MBone at two or more topologically
distinct points or
- Someone trying to use a PIM cloud as an MBone transit net.
Neither of these things will work. But, despite numerous pious
claims from cisco that they have told their customers these
things won't work, several major providers & backbone sites keep
trying them. I would guess that the duplicates you're seeing
are happening either in Stockholm or near mae-east in the US
(there are pim routers both places). Someone needs to look at
the traffic going into & coming out of the international links
to localize it better. FYI, I'm not seeing any duplicates on
the NASA session but, of course, there aren't any pim routers
between NASA & my workstation.
- Van
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