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

[Colin Perkins]

On 13 Feb 2006, at 19:05, 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).
...

A long term solution along these lines would be to adopt SIP as part  
of the signalling mechanisms for AccessGrid, since many firewall/NAT  
devices these days are becoming SIP aware to support VoIP  
applications, and can snoop on the signalling to open the required  
ports. That's a huge job though, and not a near term solution...

Colin