[dvblast-devel] patch SAP announcements generated from sdt

[Andy Gatward]

Hi,

>we are looking forward to your feedback/comments. we know that it is
>just a very limited version, but the basic functionality is working fine
>for us (ipv4 + rtp + dvb-s).

This is something I have been considering for a while and decided not to
do, rather leave it to dedicated tools that can do the job properly.
However, some hopefully constructive feedback on what you've done:

1) I suggest you go and re-read RFC2974 regarding scoping of SAP
announcements as what has been implemented is technically incorrect
regarding scoping.

2) Many sites that have internet multicast routing enabled actually 
block org-scoped addresses at the VLAN boundary due to some UPnP / mDNS
nastiness.

3) Ideally, you'd also allow an announcement group to be set - if you've
seen the SAP announcement list when you have internet multicast routing
enabled, you'll know why!

4) While using TTL to limit propagation of announcements is discouraged 
in the RFC, it is a requirement where there are legal restrictions on 
the scope of a 'broadcast', so limiting the SAP announcements to the 
same TTL as the multicast output would probably be a sensible move, or 
at least adding another override.

>in general do you like the idea of integrated announce protocols?

Personally, no.  DVBlast was deliberately designed to be simple, clean,
and do one job; however I can see that others may like this.

Andy.