RE: MPE Question

["Summers Edwin" <summers_edwin@bah.com>]

Greetings,

While researching MPE and the proposed ULE spec, I ran across some
information that I cannot equate.

If I read table 3 of EN 301 193 v1.4.1 (DVB spec for data broadcasting)
correctly, the overhead of an MPE section is 16 bytes (assuming LLC/SNAP
not used).  But while researching MPE I found a brief by Vladimir
Ksinant, Alain Ritoux, and "fritsche" entitled "Using ULE for IPv4/v6 in
MPEG-2 encapsulation" (12/11/2003) that states there is 17 bytes of
header/trailer for IPv4 packets encapsulated by MPE, and 25 bytes for
IPv6, assuming use of LLC/SNAP.

1) For a section encapsulating an IPv4 packet and not using LLC/SNAP, is
the overhead 16 or 17 bytes? (same for ULE...I count 8 bytes in
draft-ietf-ipdvb-ule-05 section 4 where the above document states 9
bytes, when not using the destination address) 

2) (for MPE) If my original calculation of 16 bytes is correct, then
would the overhead for a section using LLC/SNAP be 24 bytes (16 + 8 byte
LLC/SNAP)?

3) Do current MPE implementations in IPv6 networks require the use of
LLC/SNAP in the section?  I know this was discussed on the list some
time ago, and I believe the reason for it was because MPE does not
include a type field, where ULE does.  Are there any current MPE
implementations that do not require LLC/SNAP for IPv6 packets?

Thanks in advance!
Ed

--------------------
Ed Summers
Booz Allen Hamilton
(o) 703.377.1407
(f) 703.902.3409