RAS terminal and gateway discovery/registration messages

Gene Schroeder erschroeder at LUCENT.COM
Tue Nov 2 10:53:31 EST 1999


Rex,

I think we are talking about two meanings of registering multiple times.

I believe the proposals you mention relate to a single, (logical) endpoint
registering multiple times to augment alias lists, etc.  The key is that
for each registration, the gatekeeper is aware that the same logical
endpoint is involved, and it is simply augmenting/editing registration information
for an already-registered endpoint.

What I was trying to say was that if a physical device registers as if
it were multiple logical endpoints, then in practice the registrations can't
or shouldn't use the same transport address.  In this case, the gatekeeper is
not (in principle) aware that the same physical device is acting as multiple
endpoints.  Rather, it sees N independent RRQs.  If the RRQs share transport
addresses, things will probably not work as expected.  Now, per the proposals
you mention, each of these logical endpoints could themselves register multiple
times, but that is the other meaning of multiple....

Gene Schroeder
elemedia
    -----Original Message-----
    From: Rex Coldren <coldrenr at agcs.com>
    To: ITU-SG16 at mailbag.cps.intel.com <ITU-SG16 at mailbag.cps.intel.com>
    Date: Tuesday, November 02, 1999 10:23 AM
    Subject: Re: RAS terminal and gateway discovery/registration messages
    
    
    Gene, 
       It is not true that a device that registers multiple times must use different 
    transport addresses.  At least not in H.225 v4.  Have a look at Berlin APC 
    1581 and TD 27.  These proposals cover additive registration capabilities for 
    an endpoint. 
    ftp://standard.pictel.com/avc-site/9908_Ber/ 

    Rex Coldren 
    +1 623 582 7883 

    Gene Schroeder wrote: 

         Regarding your first question, I believe that H.225 is simply saying that a physicaldevice can register as multiple logical endpoints, and this might be most commonfor a GW or MCU.  It certainly doesn't mean that a PSTN GW would register oncefor each line.  However, a GW could partition its lines in some way, and registeronce for each grouping.  By the way, while it is not stated explicitly, I believe thatin practice a device that registers multiple times must use different transportaddresses (IP-port combination) in each registration, to allow each logicalendpoint to be individually addressed. Regarding your second question, a GW might register an alias for administrativeor management purposes. Gene Schroederelemedia 
            -----Original Message----- 
            From: Mohamed Mustafa <M.Mustafa at SDXPLC.COM> 
            To: ITU-SG16 at mailbag.cps.intel.com <ITU-SG16 at mailbag.cps.intel.com> 
            Date: Tuesday, November 02, 1999 6:50 AM 
            Subject: RAS terminal and gateway discovery/registration messages 
             Hi All, 
            H.225.0 states that "one GRQ is sent per logical endpoint; thus an MCU or a Gateway might send many". Do I take it therefore, that a H.323-to-ISDN gateway with a maximum capacity of n lines must send n GRQ and RRQ messages; i.e., one for each line? If this is the case, can anyone shed any light on the reasoning behind it? 

            Also, can anyone explain the relevance of the endpointAlias field in the GRQ message and the terminalAlias fields in the RRQ and RCF messages to a H.323 gateway application? After all, a gateway is supposed to be transparent to normal endpoints and does not need to be directly addressed by them. 

            Thanks, 

            Mohamed

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