All things related to multicast

["Lucy E. Lynch" <>]

James -

I believe this is a problem with the base code for SDR & XMIM -
and it is difinately size drive not character driven. Not just
a linux problem (I can do this with Solaris as well). Given that
SAP is the current "standard" for broacast announcements I would
think we sould look at the requirements in the RFC and see if this
limit is nessesary - if it is, than we should follow up with any
vendor that allows over-size announcements, if its not - then we'll
need to work on a fix for SDR (a standard tool) and XMIM -

Not just a UO problem - this is a multicast community problem if we
want to continue to support SAP/SDR

Lucy E. Lynch                           Academic User Services
Computing Center                        University of Oregon

                (541) 346-1774/Cell: 912-7998

On Mon, 13 May 2002, James O. Whitlock wrote:

> What then is the issue/problem and who needs to correct it?  Are there
> RFC based specs that are being ignored by IP/TV or is there a bug in
> the client release that needs to be fixed, at least to keep from
> crashing systems?  And is there a work-around for the client?  Do we
> even know if it's message length or a particular character that knocks
> you off the air?  And is it Linux only, a particular release of Linux
> or what?  I'll be happy to pick up the thread with Cisco if it appears
> to be their problem.  But we'd need more specifics to much on any front.
> Assuming you want to chase this at all.  -- Jim
>
>
> ----- Original Message -----
> From: "Lucy E. Lynch" 
> <>
> To: "James O. Whitlock" 
> <>
> Sent: Monday, May 13, 2002 1:58 PM
> Subject: Re: USA WNY-HPNVI 24/7 Live Surgery at 1330 EST (fwd)
>
>
> > James -
> >
> > Bill reports seeing the same kinds os errors - maybe I'm just
> > the canary in the coal mine.
> >
> > Lucy E. Lynch Academic User Services
> > Computing Center University of Oregon
> > 
> >  (541) 346-1774/Cell: 912-7998
> >
> > On Mon, 13 May 2002, James O. Whitlock wrote:
> >
> > > Well, we were connected before that using other than the current
> > > routers.  It's not really new at all.  We shook down multicast
> > > connectivity to SURFNet sometime in early spring of 2001.  I don't
> > > even know if Bill was involved.  If need be, I can track back and
> > > get more precise info.  It remains the case, in any event, that
> > > you're the only one with reported problems.  -- Jim
> > >
> > > ----- Original Message -----
> > > From: "Lucy E. Lynch" 
> > > <>
> > > To: "James O. Whitlock" 
> > > <>
> > > Sent: Monday, May 13, 2002 1:47 PM
> > > Subject: Re: USA WNY-HPNVI 24/7 Live Surgery at 1330 EST (fwd)
> > >
> > >
> > > > FYI
> > > >
> > > > Bill says you've only been connected to Abilene's multicast
> > > > backbone since April - this may never have been a problem
> > > > on your internal network - but it is for global SAP -
> > > >
> > > > Lucy E. Lynch Academic User Services
> > > > Computing Center University of Oregon
> > > > 
> > > >  (541) 346-1774/Cell: 912-7998
> > > >
> > > > ---------- Forwarded message ----------
> > > > Date: Mon, 13 May 2002 07:55:21 -0700 (PDT)
> > > > From: Lucy E. Lynch 
> > > > <>
> > > > To: Bill Owens 
> > > > <>
> > > > Cc: 
> > > > ,
> > > >  
> > > > 
> > > > Subject: Re: USA  WNY-HPNVI 24/7 Live Surgery at 1330 EST
> > > >
> > > > Bill -
> > > >
> > > > Additional testing on our end (thanks to Jon Miyake) shows that
> > > > any large announcement will break both SDR & XMIM (info field,
> > > > subject field etc.) and it appears that this is related to
> > > > the strong suggestion in the RFC:
> > > >
> > > > RFC 2974             Session Announcement Protocol          October 
> > > > 2000
> > > >
> > > >    RECOMMENDED that SAP packets are smaller than 1kByte in length,
> > > >    although if it is known that announcements will use a network with 
> > > > a
> > > >    smaller MTU than this, then that SHOULD be used as the maximum
> > > >    recommended packet size
> > > >
> > > > Not sure if IP/TV & VBrick have the same limitations built in.
> > > >
> > > > Lucy E. Lynch Academic User Services
> > > > Computing Center University of Oregon
> > > > 
> > > >  (541) 346-1774/Cell: 912-7998
> > > >
> > > > On Mon, 13 May 2002, Bill Owens wrote:
> > > >
> > > > > At 11:07 -0700 5/10/02, Lucy E. Lynch wrote:
> > > > > >James -
> > > > > >
> > > > > >I'm using both SDR v2.8 and xmim 
> > > > > >(see:http://videolab.uoregon.edu/mim/)
> > > > > >to try and gather sap announcements on a linux box (redhat 7.1) -
> > > > > >XMIM will collect announcements for a while and then seg faults -
> > > > > >while sdr manages to collect announcements and stay up - but if I
> > > > > >exit and then re-start it dumps core.
> > > > >
> > > > > I have seen the same symptoms here, with SDR 2.8. I am also running
> > > > > the sdr-monitor TCL script, I'm not sure if that makes any 
> > > > > difference.
> > > > >
> > > > > BTW, the University at Buffalo did not have multicast connectivity
> > > > > until very recently, April 25 to be exact. Prior to that date Jim 
> > > > > was
> > > > > presumably running this session unicast, or with a point-to-point
> > > > > tunnel that didn't touch the MBONE.
> > > > >
> > > > > Bill.
> > > > >
> > > >
> > > >
> > > >
> > > >
> > >
> >
> >
> >
>