Re: Replay protection

Steve Brown

Hi Johan,

On Sat, 2017-12-09 at 22:58 +0200, Johan Hedberg wrote:
Hi Steve,

On Sat, Dec 09, 2017, Steve Brown wrote:
These are publish retransmits. However, the transaction ID's in the
received messages are all the same. It's the "trans_id" field in
log in my earlier post.
If I understand right, then the transaction id is a model-layer
so you'd need to take care of correct handling of duplicates in your
message handler.

An upper layer, like my server, getting multiple messages with the
sequence number isn't what I'd expect. What am I missing?
Are you mixing transaction id (a model layer feature) and sequence
number (network/transport layer feature)? I didn't see any indication
that your handlers would be getting the same squence number multiple
times, rather they're getting the same transaction id multiple times.
Sequence number duplicates should get filtered out latest by the
transport layer's replay protection (if the network message cache
catch them before that).

Yes, I've conflated sequence number and transaction id.

It's clear now.

Thanks for the clarification,


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