Subject: [quicwg/base-drafts] Relax 1200B requirement for Initial ACKs/Retx (#1916)

From: martinduke <[email-masked]>
Date: Thu, 25 Oct 2018 09:48:10 -0700

IMO it's silly to pad out a packet that contains the client's initial and handshake acks, because if delivered it verifies the address.
You can view, comment on, or merge this pull request online at:

  https://github.com/quicwg/base-drafts/pull/1916

-- Commit Summary --

  * Relax 1200B requirement for Initial ACKs/Retx

-- File Changes --

    M draft-ietf-quic-transport.md (7)

-- Patch Links --

https://github.com/quicwg/base-drafts/pull/1916.patch
https://github.com/quicwg/base-drafts/pull/1916.diff

-- 
You are receiving this because you are subscribed to this thread.
Reply to this email directly or view it on GitHub:
https://github.com/quicwg/base-drafts/pull/1916

---

From: MikkelFJ <[email-masked]>
Date: Thu, 25 Oct 2018 09:53:09 -0700

More generally, it would be good if the 1200B restraint could be entirely replaced by increased latency by sending a probe packet of sorts.

IoT devices might want to have a smaller tranmissions buffer.

I'm not sure how much TLS overhead can be reduced, but that could be a larger cost.

-- 
You are receiving this because you are subscribed to this thread.
Reply to this email directly or view it on GitHub:
https://github.com/quicwg/base-drafts/pull/1916#issuecomment-433126379

---

From: Martin Thomson <[email-masked]>
Date: Thu, 25 Oct 2018 16:31:29 -0700

I was going to edit this directly, but it was a bigger change.  Does https://github.com/martinduke/base-drafts/pull/1 work for you @martinduke ?

-- 
You are receiving this because you are subscribed to this thread.
Reply to this email directly or view it on GitHub:
https://github.com/quicwg/base-drafts/pull/1916#issuecomment-433239002

---

From: Martin Thomson <[email-masked]>
Date: Thu, 25 Oct 2018 16:33:11 -0700

@mikkelfj, in practice, there is a probe.  The server sends what it can, which - in most of the cases where it is limited - includes a Handshake packet.  That Handshake packet is the probe.  The acknowledgment of that Handshake packet is the response to that probe.  It's implicit, that's all.

-- 
You are receiving this because you are subscribed to this thread.
Reply to this email directly or view it on GitHub:
https://github.com/quicwg/base-drafts/pull/1916#issuecomment-433239298

---

From: martinduke <[email-masked]>
Date: Mon, 29 Oct 2018 20:39:14 -0700

@martinduke pushed 3 commits.

d6be519  Suggestion for #1916
1da29df  If the server gets Handshake, it's unconstrained
3081d81  Merge pull request #1 from quicwg/fix1916

-- 
You are receiving this because you are subscribed to this thread.
View it on GitHub:
https://github.com/quicwg/base-drafts/pull/1916/files/add33c6a96401317f0d462c445a78fd12b1e64d1..3081d814d42e2957e8fb12057af47767cdffe6c7

---

From: martinduke <[email-masked]>
Date: Mon, 29 Oct 2018 20:42:51 -0700

My github-fu is weak, but I believe this is ready to merge to master.

-- 
You are receiving this because you are subscribed to this thread.
Reply to this email directly or view it on GitHub:
https://github.com/quicwg/base-drafts/pull/1916#issuecomment-434161292

---

From: Martin Thomson <[email-masked]>
Date: Mon, 29 Oct 2018 21:07:31 -0700

Merged #1916 into master.

-- 
You are receiving this because you are subscribed to this thread.
Reply to this email directly or view it on GitHub:
https://github.com/quicwg/base-drafts/pull/1916#event-1934014372

---

From: Martin Thomson <[email-masked]>
Date: Mon, 29 Oct 2018 21:07:40 -0700

I agree.  Thanks for persisting Martin.

-- 
You are receiving this because you are subscribed to this thread.
Reply to this email directly or view it on GitHub:
https://github.com/quicwg/base-drafts/pull/1916#issuecomment-434165019

---

From: MikkelFJ <[email-masked]>
Date: Tue, 30 Oct 2018 01:22:25 -0700

mikkelfj commented on this pull request.

> @@ -1556,9 +1556,9 @@ times as many bytes as the number of bytes they have received.  This limits the
 magnitude of any amplification attack that can be mounted using spoofed source
 addresses.
 
-If sending a UDP datagram consisting entirely of an Initial Packet, clients
-MUST pad that packet to at least 1200 bytes unless the client has received a
-Handshake Packet ack from the server. This ensures that the server is not
+Clients MUST pad UDP datagrams that contain only Initial packets to 1200 octets.
+Once a client has received an acknowledgment for a Handshake packet it MAY send
+smaller datagrams.  Sending padded datagrams ensures that the server is not

What is the intent here? Why would you send an Initial packet if you have received ACK for a handshake packet. Why isn't ACK of the initial packet sufficient. "smaller datagrams" could refer to datagrams without Initial packets.

-- 
You are receiving this because you are subscribed to this thread.
Reply to this email directly or view it on GitHub:
https://github.com/quicwg/base-drafts/pull/1916#pullrequestreview-169652544