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Date:      Sat, 25 Dec 1999 12:59:50 -0800 (PST)
From:      "B. Scott Michel" <scottm@CS.UCLA.EDU>
To:        Glendon Gross <gross@clones.com>
Cc:        Jonathan Lemon <jlemon@americantv.com>, Matthew Dillon <dillon@apollo.backplane.com>, Brad Knowles <brad@shub-internet.org>, Joe Abley <jabley@patho.gen.nz>, Poul-Henning Kamp <phk@critter.freebsd.dk>, Garrett Wollman <wollman@khavrinen.lcs.mit.edu>, freebsd-current@freebsd.org
Subject:   Re: Odd TCP glitches in new currents
Message-ID:  <Pine.BSF.4.10.9912251256440.6878-100000@mordred.cs.ucla.edu>
In-Reply-To: <Pine.LNX.4.05.9912240941570.7749-100000@dell.orlybeauty.com>

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We aren't doing mcast at this time. If there's anyone from Nortel
lurking behind this list, UCLA CS is pretty close to throwing out
the Accelars due to a lack of tech support response.

No, UCLA CS is not capable of doing department-wide mcast because
of a set of peculiar bugs in the Accelar's code. It will only do
DVMRP snooping on a limited number of mcast groups (~400 or so).
What we actually see is 3x that number. And so we're waiting for
some upgraded code that Nortel/Bay has claimed is coming for the
better part of a year now.


-scooter


On Fri, 24 Dec 1999, Glendon Gross wrote:

> 
> Are you sure that this is a problem with the local interface dropping
> packets, or could it just be a multicast router
> that is suppressing packets?  I have noticed with my new FreeBSD box 
> running mrouted, exceptionally good routing performance.  But my linux
> boxes are more consistent in their response.  So I concluded that 
> my upstream neighbors are supressing the broadcasts as a feature of the
> multicast routing protocol.  I don't think it's a problem with my local
> interface, just a feature of the DVMRP protocol.  
> 
> Can anyone recommend a good reference on this?  I've been reading RFC-1075
> and don't really understand it.    --Glen Gross
> 
> On Tue, 30 Nov 1999, B. Scott Michel wrote:
> 
> > On Wed, 22 Dec 1999, Jonathan Lemon wrote:
> > 
> > > On Dec 12, 1999 at 11:37:42AM -0800, Matthew Dillon wrote:
> > > I had a Netgear FS509 switch here that would eat packets transmitted
> > > through the GigE port under certain conditions.  Netgear shipped me 
> > > a new one, and I've been happy with it, until the same problem started
> > > happening again this morning.
> > 
> > There's some oddities in the 3.3 and 3.4 kernels as well -- I've actually
> > nailed down the plexicity and speed on both the Accellar and my humble PC,
> > and yet, I'm looking at weird TCP lockups from time to time.
> > 
> > Mostly seems to be related to NFSv3, but will also happen when doing
> > cvsup. There's no magic number of how many bytes are queued waiting to go
> > out the interface. And it seems to be limited to specific connections,
> > i.e. an NFS TCP connection can be jammed and yet I can be happily talking
> > to cvsup3 doing an update.
> > 
> > The interface in question is a NetGear:
> > 
> > pn0: <82c169 PNIC 10/100BaseTX> rev 0x20 int a irq 11 on pci0.9.0
> > 
> > What is odd is that the output error metric from netstat -in monotonically
> > increases.
> > 
> > Yes, I could post my configuration, etc., and I could go back to running
> > -current, but I have a PhD to make progress on. And I'm willing to wait to
> > try out the consolidated 2x040/PNIC driver when 4.0 finally rolls out.
> > 
> > 
> > -scooter
> > 
> > 
> > 
> > To Unsubscribe: send mail to majordomo@FreeBSD.org
> > with "unsubscribe freebsd-current" in the body of the message
> > 
> > 
> 

Scott Michel                        | No research ideal ever survives
UCLA Computer Science		    | contact with implementation.
PhD Graduate Student                | 



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