RE: Differences between INT and MMT tables for address resolution?

[Harald Skinnemoen <harald.skinnemoen@nera.no>]

I can add the following info: 

The use of MMT was input to the ESA
SatLabs group by SES Astra, and in in their Recommendation for DVB-RCS,
just recently publihed. It's based on a specific implementation. The "problem",
if you wish, with MMT is that it is quite limited, and does not allow a
multicast stream to e.g. be split on two more more downlink beams. The
use of INT tables does, and can do more than just map IP multicast addresses
to PIDs as I understand. The SatLabs doc (which can be freely downloaded
from the ESA/Estec website) says IGMP is not to be used over the satelilte
link, only locally.

Both options appear to be (with my limited
knowledge) restricted to (or at least best suited for) static multicast,
where a service provider predefines a set of groups that a user can wish
to subscribe to or not. If your favorite group is not there, then it's
not obvious how you can ask for it in an integrated process. Further, it
seems to me that one risks sending groups with no listeners (I may be wrong
here, so I'm happy for any input).

I'm basically looking for ways of doing
dynamic multicast over DVB-RCS, and how this would potentially interact
with MMT and INT (or even other ways if relevant)

I am working with a spec on this topic
for ETSI (WG BSM), and looking for input and information on DVB-RCS and
multicast in general. Also - Nera (where I work) has done some work on
dynamic multicast, but in this case all multicast is sent with one and
the same PID.

Any info is appreciated. 

/harald

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Subject:        RE: Differences between INT and MMT tables for address resolution?

Hi Harald et al.
 
Though I'm not exactly up-to-date on this, Astra TRP 1053 seems to carry INT for unicast (19.2 DegEast, 10.77325 GHz, Horizontal, 22MS/s, 5/6) (a colleage told me)
 
With reference to Frank's earlier question: INT is now specified and officially (ETSI) standardised in ETSI EN 301 192 V1.3.1 (2003-05). No other reference should be used, unless the standard is updated, which can be "polled" from the www.etsi.org site using the "data broadcasting" string in the keyword search for "get a standard / free download".
 
Given that the specification only became an official ETSI standard in May, it would suprise me if there are already many implemenations to choose from, since ETSI works more towards concensus, standard, implementation, rather than the IETF, implement, concensus, standard. (I am certain there are several proprietry implementations based on one of the proposals before INT was designed by concesus, which should migrate to INT over time).
 
Does anyone have an MMT reference (to standard or standards contribution)? Since it is DVB-RCS specific, I had a look at the DVB-RC* ones listed at www.dvb.org (based on the "mmt" and "multicast" strings):
* DVB-RCC (return channel for cable): ES 200 800; TR101 196 says use EN 301 192 for MAC/IP mapping
* DVB-RCL (return channel for LMDS): EN 301 199; TR 101 205 says use EN 301 192 for MAC/IP mapping
* DVB-RCT (return channel for terrestrial) : EN 301 958 says use EN 301 192 for MAC/IP mapping
* DVB-RCG (GSM): EN 301 195 says nothing
* DVB-RCP (PSTN/ISDN): ETS 300 801 says nothing
* DVB:RCCS (SMATV + measurement guidelines): TR 101 201; TR 101 290 say nothing
 
DVB-RCS: Digital Video Broadcasting (DVB); Interaction channel for satellite distribution systems) documents say this:
* ETSI TR 101 790 V1.2.1 (2003-01) - guidelines - says a fair amount about multicast including: Multicast PID Mapping Table (identified by the Elementary Loop with the stream type = 0x05 and table id = 0xA7 in the RCS content descriptor) parsed from PMT using IP/DVB Service linkage from RCS/Map Table. However, this Multicast PID Mapping table is neither referenced nor specified.
* ETSI EN 301 790 V1.3.1 (2003-03) - standard/specification - says nothing
 
(nothing = nothing in respect to mmt & multicast :)
 
Thus I can conclude that MMT = Multicast PID Mapping Table and was mentioned as recently at January 2003, but not is in the DVB-RCS standard, only in the guidelines. Does anyone have a reference to the specification?
 
Cheers, Rod.
 
-----Original Message-----
From: ext Harald Skinnemoen [mailto:harald.skinnemoen@nera.no]
Sent: Monday, August 18, 2003 5:57 PM
To: ip-dvb@erg.abdn.ac.uk
Cc: IP-dvb@erg.abdn.ac.uk
Subject: Re: Differences between INT and MMT tables for address resolution?


Hi all,

I'm looking for some further info on the practical use of the INT tables.  Does anybody know of anyone who has implemented satellite multicast by using the INT tables?

Seems to me the MMT tables are used in at least a couple of systems. I'm however not sure how users satisfaction is, as it seems to me it can't offer the same dynamics and flexibility as a terrestrial IP multicast system.

Best regards,

/Harald
 

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Subject:        Differences between  INT and MMT tables for address resolution?


Before delving into the DVB archives, does somebody know:

a. Where the Multicast Map Table is officially defined ? Is there a DVB
reference ?

b. What is the relation between the INT (IP/MAC Notification Table) , as
defined in ETSI EN Draft 301 192 v1.3.1 (2002-12) ? In addition to offering
unicast/MAC streams/platform concept, is it  making the MMT obsolete  ? Is
there a reference to minutes of some DVB meeting that explains the relation
between the two ?

My understanding is that EN 301 192 v1.3.1 (DVB data broadcasting)  document
now includes the document referenced in Gorries report from Atlanta (ETSI EN
drTS 102 00X V0.4.2 (2002-07) "Specification for IP Notification in DVB
Systems Use of the IP/MAC Notification Table").


Regards, Frank