[AG-TECH] One-page summary of AG port usage -- please help us complete it

Tue Feb 14 13:02:27 CST 2006

I'm gonna try to take a practical line here.  First, some clarification:

- By default, the VenueServer allocates multicast addresses dynamically as follows:
    address range:  224.2.128.0 - 224.2.255.254
    port range:  49152-65535

- "Dynamic" in this case means that addresses are allocated when someone
    enters the venue, and are recycled when the last person leaves the venue.

- "Static" (the opposite of Dynamic) means that addresses/ports are assigned
    to a venue by the admin, and do not change.

- VenueServer admins can, through provided tools, configure the address
    range however they like.  There is currently no option for configuring the
    port range, but there probably should be.

- The BridgeServer does provide a mechanism for configuring the port range
    used for bridges.  By default, it uses ports in the range 49152-65535.

One thing we could do is significantly narrow the range of addresses and ports
used by the VenueServer and BridgeServer by default.  This would make the
default case easier for everyone to deal with.  It would also, unfortunately, open
us up to more likely address redundancy across Venues.

Whatever is done, it should clearly be subject to the user community.

What are the concerns of your admins?
Do they care at all about opening up the multicast address range?  Why?
Would it be enough to be able to select a bridge with a known port range that 
would work for any venue?

I think the real problem is in bridging, where you're concerned with traffic from
real hosts.  But let's get input from some of those (Draconian) net admins and 
build
a practical solution.

Frank Sweetser, other net admins:  Are you listening?

Tom Uram

On 2/13/06 1:05 PM, R. P. Channing ["Rick"] Rodgers wrote:
>> From: "Ivan R. Judson" <judson at mcs.anl.gov>
>> Subject: RE: [AG-TECH] One-page summary of AG port usage -- please help us 
> complete it
>> Date: Mon, 13 Feb 2006 11:41:32 -0600
>>
>>
>> I think what you're hearing is unwillingness for anyone to commit to a wrong
>> answer. 
>>
>> From memory, the ports for vic, rat, and the rest of the tools are allocated
>> by the venue server. It can be a static allocation configured by the
>> provider or a dynamic allocation (I think the default). 
> 
> Perhaps my understanding is faulty, but I also believe that the default is
> automated assignment by the server.  But that can not be entirely random --
> the numbers must be drawn from a range of values appearing somewhere in the
> code.  Having that range in a doc. is much better than having nothing,
> which is what he have now.
> 
> A subsequent posting from Zsolt Nagykaldi makes the point, which I emphatically
> agree with, that port assignment is a crucial problem to solve if AG is truly
> going to take off.  He suggests using fixed port numbers with a registry, which
> is one solution (and by "fixed" I believe he means that required ports would
> remain the same for a given venue over time).  Another might be to adapt or
> create a protocol allowing the exchange of port numbers when entering a venue
> (which would at least tell you what ports were required, even if they don't
> happen to be open at the moment).  Another might be to devise a tunnelling
> mechanism through a number of fixed ports which are permanently assigned for
> that purpose, sort of a port-related sibling to the multicast-unicast bridging
> that the AG can do now.  This would allow people working in tightly constrained
> networks to use the AG, at the cost of some performance penalty.
> 
> Whatever solution is ultimately pursued, dealing with the port issue is the
> single most important single technical issue I see right now on with AG.  It
> has certainly been delaying our deployment at the UCSSF medical center.
> This document helps focus our attention on the problem, and I hope we can get
> help completing it.  it needs to be accompanied by fuher instructions related
> to port assignment (r.g., how they can be statically configured).
> 
> Cheers, Rick Rodgers
> 
>> Given this configurability, it's impossible to state exactly what ports the
>> media tools will or won't use.
>>
>> Sorry for the complicated answer.
>>
>> --Ivan
>>
>>> -----Original Message-----
>>> From: owner-ag-tech at mcs.anl.gov [mailto:owner-ag-tech at mcs.anl.gov] On
>>> Behalf Of R. P. Channing ["Rick"] Rodgers
>>> Sent: Monday, February 13, 2006 11:36 AM
>>> To: rodgers at nlm.nih.gov; ag-tech at mcs.anl.gov; michael.daw at manchester.ac.uk
>>> Cc: bernholdtde at ornl.gov; jsummers at bachman.cs.ou.edu;
>>> terrazas at labmed2.ucsf.edu
>>> Subject: RE: [AG-TECH] One-page summary of AG port usage -- please help us
>>> complete it
>>>
>>> Michael,
>>>
>>> Thanks, I agree that AG Central would be an excellent development resource
>>> and then final home for our summary of AG port usage.  We certainly need
>>> help completing it.  The biggest gap right now is port ranges for vic and
>>> rat.
>>> I just *know* that folks working with the code for these applications more
>>> actively than we do could produce these numbers in a few minutes.
>>>
>>> In browsing around in the AG Central forums, it appears that they have
>>> only
>>> received light traffic thus far, not that that should stop us from helping
>>> to
>>> kick-start the community there.  It's not clear which forums would be
>>> optimal
>>> for our purposes -- I suppose "AG Toolkit/General"?  So I'm taking your
>>> advice,
>>> reattaching our two documents here, and also posting my original message
>>> to
>>> "AG Toolkit/General" on the forum at http://agcentral.org as wel.
>>>
>>> CORRECTION: just tried to do the above, and got completely wedged -- not
>>> clear that I have permissions to post to the forum, even though I'm
>>> registered.
>>> Then my web client got completely stuck.  Will try again later, sigh...
>>>
>>> Cheers, Rick Rodgers
>>>
>>>> From: "Michael Daw" <michael.daw at manchester.ac.uk>
>>>> Subject: RE: [AG-TECH] One-page summary of AG port usage -- please help
>>> us
>>> complete it
>>>> Date: Mon, 13 Feb 2006 09:43:55 +0000
>>>>
>>>> Great work guys! This is going to be good.
>>>>
>>>> But, can I suggest using http://agcentral.org for this? If the document
>>> is
>>> discussed and refined in a forum, it will be easy to find. Once it's
>>> ready, it
>>> can be posted to the help center. Because most of us still aren't
>>> completely
>>> used to using agcentral, you can always post frequently to ag-tech too
>>> with
>>> pointers.
>>>>
>>>>> -----Original Message-----
>>>>> From: owner-ag-tech at mcs.anl.gov
>>>>> [mailto:owner-ag-tech at mcs.anl.gov] On Behalf Of R. P.
>>>>> Channing ["Rick"] Rodgers
>>>>> Sent: 10 February 2006 20:21
>>>>> To: ag-tech at mcs.anl.gov
>>>>> Cc: rodgers at nlm.nih.gov; bernholdtde at ornl.gov;
>>>>> jsummers at bachman.cs.ou.edu; terrazas at labmed2.ucsf.edu
>>>>> Subject: [AG-TECH] One-page summary of AG port usage --
>>>>> please help us complete it
>>>>>
>>>>> Dear AG Colleagues,
>>>>>
>>>>> I now realize that the work I started last December, trying
>>>>> to create a
>>>>> one-page summary of AG port usage (based on the commendable
>>>>> document created by
>>>>> Javier Gomez Alonso of the Access Grid Support Centre at the
>>>>> University
>>>>> of Manchester) is not easily locatable in the list archives.
>>>>> I resend it,
>>>>> attached, along with the Excel version that David E.
>>>>> Bernholdt of ORNL kindly
>>>>> created.  As I said earlier, all of these documents are missing some
>>>>> key information, such as the port ranges used by vic and rat.
>>>>>  I send this out
>>>>> again in the hope that another AG colleague will pick it up
>>>>> and complete it.
>>>>> We all really need to have something like this, and i would
>>>>> hope that eventually
>>>>> it would end up on the AG web site(s), and be maintained to
>>>>> reflect any
>>>>> coding changes/additions made to AG software.
>>>>>
>>>>> Best Regards, Rick Rodgers
>>>>>
>>>>> --------------------------------------------------------------
>>>>> ------------------
>>>>> R. P. C. Rodgers, M.D. * rodgers at nlm.nih.gov * (301)435-3267
>>>>> (voice, fax)
>>>>> OHPCC, LHNCBC, U.S. National Library of Medicine, NIH
>>>>> Bldg 38, Rm. B1N-30F2, 8600 Rockville Pike, Bethesda MD 20894 USA
>>>>> http://lhc.nlm.nih.gov/staff/rodgers/rodgers.html
>>>>>
>>>>>
>>>>>
>>> --------------------------------------------------------------------------
>>> ------
>>> R. P. C. Rodgers, M.D. * rodgers at nlm.nih.gov * (301)435-3267 (voice, fax)
>>> OHPCC, LHNCBC, U.S. National Library of Medicine, NIH
>>> Bldg 38, Rm. B1N-30F2, 8600 Rockville Pike, Bethesda MD 20894 USA
>>> http://lhc.nlm.nih.gov/staff/rodgers/rodgers.html
> 
> --------------------------------------------------------------------------------
> R. P. C. Rodgers, M.D. * rodgers at nlm.nih.gov * (301)435-3267 (voice, fax)
> OHPCC, LHNCBC, U.S. National Library of Medicine, NIH
> Bldg 38, Rm. B1N-30F2, 8600 Rockville Pike, Bethesda MD 20894 USA
> http://lhc.nlm.nih.gov/staff/rodgers/rodgers.html
> 
> 