Open issue 15: chunk with a too short length

[Benoit Claise <bclaise@cisco.com>]

Dear all,

From the Vancouver meeting minutes:

Open Issue (not numbered): Chunk with too short length
How to encode "chunk" with a too short length? Padding wouldn't be recognized
by the collector. One solution would be using a new template for each length.
Proposal: The protocol draft should say that padding MUST NOT be used for
variable length IEs.

Here is a new proposed text (actually, only the second paragraph is new)

Basic Packet Report

For each selected packet, the Packet Report MUST contain the following information:
- The associationsId Information Element
- Some number of contiguous bytes from the start of the packet, including the packet header (which includes link layer, network layer and other encapsulation headers) and some subsequent bytes of the packet payload.  Alternatively, the number of contiguous bytes may start at the beginning of the payload. The Layer2PacketSection, l2PayloadPacketSection, mplsLabelStackSection, mplsPayloadPacketSection, ipPacketSection, and ipPayloadPacketSection PSAMP Information Elements are available for this use. 
- The input sequence number(s) of any Selectors that acted on the packet, represented by the selectorInputSequenceNumber Information Element.
 
The contiguous Information Elements (Layer2PacketSection, l2PayloadPacketSection, mplsLabelStackSection, mplsPayloadPacketSection, ipPacketSection, and ipPayloadPacketSection) MAY be encoded with a fixed length field or with a variable sized field. If one of these Information Elements is encoded with a fixed length field whose length is too long for the number of contiguous bytes in the selected packet, padding MUST NOT be used. In this case, the Exporting Process MUST export the information either in a new Template Record with the correct fixed length field, or either in a new Template Record with a variable length field.  


Feedback?

Regards, Benoit.