multicast TTL settings

Bill Nickless nickless at
Mon Jun 28 13:33:50 CDT 1999

At 12:08 PM 6/28/99 -0500, Robert Olson wrote, quoting Bill Nickless:
>>It may be that each site will have their own policy for what the TTL needs
>>to be in order to participate, so this is one of the pieces of information
>>each site will need to provide.
>I think a better solution would be to set up an administrative scope for
>the AG stuff, so we don't have to worry about high-bw multicast leaking out
>from where we want it. Does that make sense?

If we were one organization, like Argonne or even cooperating sites like
vBNS, we could push out a single configuration for the administrative
scope.  But as you know, the network infrastructure is based on a bunch of
different network fiefdoms.  The effort necessary to set up an
administrative scope across all of these semi-friendly neworks would seem
to be equivalent to simply setting up multisession bridge links.  That is,
each site would have to learn how, and then implement, the administrative
scoping in the routers.

I should rephrase my paragraph above.  How does this sound?

  It may be that each site will have their own policy for what the TTL
  needs to be in order to participate in Access Grid activities.  This
  TTL may be influenced by their connectivity provider, such as vBNS, 
  Abilene, ESNet, or commercial ISP.  Accordingly, part of setting
  up an Access Grid site should be to discover the appropriate TTL setting
  necessary to get traffic offsite to other Access Grid participants.
Bill Nickless      +1 630 252 7390
PGP:0E 0F 16 80 C5 B1 69 52 E1 44 1A A5 0E 1B 74 F7     nickless at

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