Subject: [ANCP] Sub-TLVs and padding non-issue

From: Tom Taylor <[email-masked]>
Date: Thu, 01 Apr 2010 09:32:24 -0400

In the multicast extensions document, we have an example of an embedded TLV that 
does not end on a 32-bit word boundary. The example is in Figure 17 (page 
67-68). We chose to insert padding to round out the TLV to a word boundary, just 
as if it stood alone.

In the base document, immediately below Figure 13 (page 30), it is stated that:

"The value field in each TLV is padded to a 4-octet alignment."

Finally, after bullet 5 on page 33 of the base document, it is stated that:

"The general format of the sub-TLVs is identical to the general
TLV format.  The value field in each sub-TLV is padded to a
4-octet alignment."

I was worried that the treatment of padding for sub-TLVs was different from that 
for TLVs. These quotations indicate that it is not.

I believe this removes the last potential issue regarding the merger of sub-TLV 
types into the same registry as TLV types. There is no difference between a TLV 
and a sub-TLV, except that the latter happens to be embedded within another TLV.

Tom Taylor