jiebi/CodeConvo huggingface dataset:
Code change:
frames should therefore not be paced, to avoid delaying their delivery to the peer. <ins> Sending multiple packets into the network without any delay between them creates a packet burst that might cause short-term congestion and losses.  Implementations MUST either use pacing or limit such bursts to minimum of 10 * kMaxDatagramSize and max(2* kMaxDatagramSize, 14720)), the same as the recommended initial congestion window. </ins> As an example of a well-known and publicly available implementation of a flow pacer, implementers are referred to the Fair Queue packet scheduler (fq qdisc) in Linux (3.11 onwards).

Related discussion:
text: Came from the discussion of
NAME : I realized after we did this PR yesterday that this does not I It reduces burstiness in general, which is still a good thing, but it doesn't change slow start increase. I'll send a PR or ask Vidhi if she wants to.
When an ACK arrives that acknowledges N packets (where N could be very large), QUIC will increase the congestion window by more than 1MSS per congestion window during Congestion Avoidance causing bursty send. This could also affect the slow start. if (congestionwindow < ssthresh): // Slow start. congestionwindow += URL else: // Congestion avoidance. congestionwindow += kMaxDatagramSize * URL / congestionwindow One could argue that QUIC ACKs every other packet, but there ACK packet could get lost or ACK for ACK packet could get lost. The draft is probably assuming packet pacing but not all implementations support that. I discussed this with Jana and he thinks that we should add something in pseudo code or some specific text in the draft.
PR added more specific text on avoiding bursts into the network, FYI.
Please note that PR addresses the issue of app-limited or pacing-limited cases to not increase cwnd when it is under utilized. My concern is cwnd being inflated due to an ACK frame containing ACKs for large number of packets.
NAME : The problem here is that we don't talk about burstiness that can occur when pacing is not in place, and a stretch-ack is received. PRR handles this, but we don't do PRR in the draft.
No we need to spend lots of time on Reno as everybody appears to be doing Cubic or BBR?
Cubic has this problem. BBR cannot be assumed.
Except Cubic opens the window based on time spent, not just ack received
I don't get the scenario. It seems that NAME is worried about receiving an ACK for a large number of packets. This is not a congestion window problem, because it happens even if the congestion windows size remains constant. The root cause is that the ACK of N packets now reduces the number of packet in flow by N. So this is strictly about pacing, not about congestion control.
Code change:
frames should therefore not be paced, to avoid delaying their delivery to the peer. <ins> Sending multiple packets into the network without any delay between them creates a packet burst that might cause short-term congestion and losses.  Implementations MUST either use pacing or limit such bursts to minimum of 10 * kMaxDatagramSize and max(2* kMaxDatagramSize, 14720)), the same as the recommended initial congestion window. </ins> As an example of a well-known and publicly available implementation of a flow pacer, implementers are referred to the Fair Queue packet scheduler (fq qdisc) in Linux (3.11 onwards).

Related discussion:
text: NAME yes, and it can and still does burst because of stretch acks
Not just stretch Acks -- deliberate Ack compression by the network happens too. Very few alternative to pacing.
URL describes
Discussed in Cupertino. NAME to prepare a PR that hopefully can incorporate some ideas from RFC3465 to add safety features for non-pacing stacks.
But 3465 does not solve the burst problem. It limits the growth of the window, but does not do pacing of any kind.
I think we can change to something like this
NAME I think we need to do 2MSS clamping per ACK received and not per packet acked. I am thinking that we can remove OnPacketAckedCC and instead do OnAckReceivedCC. Pseudocode change something like this:
I think we can keep but just move cwnd update to as you propose.
Yup, that's an important missing fix, though it needs to be applied only when not pacing. Additionally, helps with burstiness in general. NAME : I would make a variable, and apply the min here when not pacing.
The proposed change has the effect of reducing the effective Window if ACKs are compressed. Say you have a window of 12 packets, acks are delayed, and a single ACK acknowledges 12 packets. Now you have a window of 2 packets, your transmission rate is 6 times slower than before, and it will take you 10 RTT to recover. Is that really what you want?
NAME This is what ABC (RFC 3465) does for TCP. ACK compression has side-effects, and the way to deal with it is, as you say, to pace packets out. This reduction in performance is only when the endpoint does not pace, and it is the only way to limit bursts in that case.
Also, ACK compression does not necessarily imply ACK pruning. I have traces in which 1 RTT worth of ACKs is compressed and delivered back to back. In that case, the proposed algorithm will do nothing: you will get 2 MSS added for each ACK, back to back within less than 1 ms.
FYI.
Code change:
frames should therefore not be paced, to avoid delaying their delivery to the peer. <ins> Sending multiple packets into the network without any delay between them creates a packet burst that might cause short-term congestion and losses.  Implementations MUST either use pacing or limit such bursts to minimum of 10 * kMaxDatagramSize and max(2* kMaxDatagramSize, 14720)), the same as the recommended initial congestion window. </ins> As an example of a well-known and publicly available implementation of a flow pacer, implementers are referred to the Fair Queue packet scheduler (fq qdisc) in Linux (3.11 onwards).

Related discussion:
text: FreeBSD implements rfc3465 (and enabled by default) URL Linux removed tcpabc implementation but saying it does in a different way: URL Considering FreeBSD doesn't have pacing by default, I think current proposed algorithm is not worse (or aggressive) than what tcp implementation does.
NAME I am working on the PR for pseudocode changes.
I agree that when not pacing, using an ABC limit is appropriate. FWIW Windows TCP was using a limit of 4 and not 2 for a long time and now uses 8 which is pretty close to IW10 burst in slow start phase.
For the WG: The proposed PR attempts to include a mechanism to limit CWND increase during slow start when not pacing. I'll note that by itself, it does not guarantee we follow the existing MUST: "Implementations MUST either use pacing or limit such bursts to the initial congestion window, which is recommended to be the minimum of 10 maxdatagramsize and max(2 maxdatagramsize, 14720)), where maxdatagramsize is the current maximum size of a datagram for the connection, not including UDP or IP overhead." I don't think we should add this to the pseudocode, because we say SHOULD pace packets and the pseudocode currently only covers SHOULDs, not MAYs. Adding all MAYs to the pseudocode is too complex. I don't have a concern about adding a reference to the existing RFC as a mechanism that MAY help limit bursts during slow start. I'd like a decision from the WG on whether to include this change and if so, some criteria on what should be included going forward.
I agree with the comment that burst from ACK compression or Stretch-ACKs result in bursts. I think the ways to change that is implement a maximum burst size or use pacing. The bursts do not appear a CC function to me.
Bringing conversation in from the list: With regards to , one of the things we found in testing was that it could (a) still allow an implementation to be vulnerable to too much bursting (the original problem), but more importantly (b) locked receivers into an ack pattern of acking every other packet. My main concern is that this causes problems if receivers want to experiment with and change acking strategies going forward in way that otherwise would be fine.
Code change:
frames should therefore not be paced, to avoid delaying their delivery to the peer. <ins> Sending multiple packets into the network without any delay between them creates a packet burst that might cause short-term congestion and losses.  Implementations MUST either use pacing or limit such bursts to minimum of 10 * kMaxDatagramSize and max(2* kMaxDatagramSize, 14720)), the same as the recommended initial congestion window. </ins> As an example of a well-known and publicly available implementation of a flow pacer, implementers are referred to the Fair Queue packet scheduler (fq qdisc) in Linux (3.11 onwards).

Related discussion:
text: One way to look at the problem described by this issue is that the existing text has a minor underspecification, in which it has the notion of a burst limit but says nothing about the frequency of such bursts. Two "bursts" of 10MSS that are sent within a couple nanoseconds are really one burst that's too big. Another way of fixing this is to remove even the specification of the 10MSS limit if we really don't want too much text about the non-pacing cases. Essentially, what this comes down to is: pace, or even if you don't pace, you need to not send bursts above some frequency; and if you don't set some pacing timers, you'll likely underutilize the link.
I'm going to put this out there: the answer is MUST pace. You might formalize this by saying the number of packets sent in any interval cannot exceed by more than the initial cwnd (i.e., the 10MSS). That allows for bursting, but requires a period of quiet either preceding or following any burst.
NAME Yes, it does largely reduce to "implementations MUST pace" (even if the pacing algorithm isn't very nuanced, in which case you'll perform poorly). The formalization of the rate, one option for which was specified in , I think is the heart of what should be done here.
There are two routes that we can take: Specify clearly what 'delay` refers to in the below statement, which is done in OR Change MUST pace to SHOULD and remove the 10 MSS burst size limit and provide general recommendation if an implementation doesn't pace. Something like:
I'm sympathetic to saying MUST pace, and I like the formatlization that NAME suggests. I've heard some pushback on saying MUST pace in the past, but it might be worth giving it a shot again. NAME NAME NAME : What do you think?
That said... I will note that NAME 's formalization allows for a burst at the end of an RTT. Consider for example when a single ACK is received that acknowledges an entire window. That would be legal by this definition. I think that's ok.
Discussed in ZRH. Proposed resolution is to define and REQUIRE pacing.
NAME I think requiring pacing makes good sense, with some formalization of what that means.
Code change:
frames should therefore not be paced, to avoid delaying their delivery to the peer. <ins> Sending multiple packets into the network without any delay between them creates a packet burst that might cause short-term congestion and losses.  Implementations MUST either use pacing or limit such bursts to minimum of 10 * kMaxDatagramSize and max(2* kMaxDatagramSize, 14720)), the same as the recommended initial congestion window. </ins> As an example of a well-known and publicly available implementation of a flow pacer, implementers are referred to the Fair Queue packet scheduler (fq qdisc) in Linux (3.11 onwards).

Related discussion:
text: To clarify the status here, my understanding is that the proposal is to close this design issue with no action. The discussions have identified editorial improvements that will be addressed independently.
Let's continue the editorial discussion on .
Closing this issue and continuing discussion on
This needs to run through the consensus call procedure, so we'll keep it open for another week.
Let's get this in -- it addresses some burstiness anyway.LGTM
Code change:
If Observe is implemented: <del> Replace step 1 in ver-req with: A.  Discard Code and all options marked in fig-option-protection with 'x' in column E, except for Observe, present in the received message. For example, an If-Match Outer option is discarded, Uri-Host Outer option is not discarded, Observe is not discarded. </del> <ins> Insert the following step before step 1 in ver-req: </ins> <del> Replace step 3 in ver-req with: </del> <ins> A.  Check if the Outer Observe option is present and has value zero. </ins> <del> B.  If Observe is present in the received message, and has value 0, check if the Token, kid and Partial IV are identical to a previously received Observe registration.  In this case, replay verification is postponed until step C.  Otherwise verify the 'Partial IV' parameter using the Replay Window, as described in replay-protection. </del> <ins> Insert the following step between step 6 and 7 of ver-req: </ins> <del> Insert the following steps between step 6 and 7 of ver-req: C.  If Observe was present in the received message (in step 1): If the value of Observe in the Outer message is 0: If Observe is present and has value 0 in the decrypted options, discard the Outer Observe.  If the Token, kid and Partial IV are identical to a previously received Observe registration, respond with a notification as described in observe-replay- processing; Otherwise, discard both the Outer and Inner (if present) Observe options and verify the 'Partial IV' parameter using the Replay Window, as described in replay-protection. If the value of Observe in the Outer message is not 0, discard the decrypted Observe option if present. </del> <ins> B.  If Inner Observe is present and has value zero, and Outer option is either not present or has not value 0, then remove the Observe option. </ins> 8.3.

Related discussion:
text: Back to one processing description Observe is now primarily inner Simplified processing Explicit cancellation by intermediary not supported
Code change:
If the media section proto value indicates use of RTP: <ins> If the media section references any media formats, RTP header extensions, or RTCP feedback mechanisms that were not present in the corresponding media section in the offer, this indicates a negotiation problem and MUST result in an error. </ins> If the media section has RTCP mux enabled, discard any RTCP component, and begin or continue muxing RTCP over the RTP component, as specified in RFC5761, Section 5.1.3.  Otherwise,

Related discussion:
text: Talk about what to do with header extensions in a remote description Expand discussion of how to handle payload types in a remote description Fail things we don’t know about in an answer ,
LGTM
NAME PTAL at my responses
URL If any indicated payload type is unknown, it MUST be ignored. [TODO: should fail on answers] (q: does this logic need to also include processing for other lines - extmap, rtcp-fb, etc - that weren't present in the offer?)
Fixed by
URL 2) * For each specified payload type that is also supported by the local implementation, establish a mapping between the payload type ID and the actual media format. [TODO - Justin to add more to explain mapping.]
Relevant to as well
Fixed by
URL 1) If the media section proto value indicates use of RTP: [TODO: header extensions]
LGTM
Code change:
Whether or not it implements the counter method, the server MUST NOT reuse a nonce until it switches to a configuration with new keys. <del> If the nonce is sent in plaintext, servers MUST generate nonces so that they appear to be random.  Observable correlations between plaintext nonces would provide trivial linkability between individual connections, rather than just to a common server. </del> <ins> Servers are forbidden from generating linkable plaintext nonces, because observable correlations between plaintext nonces would provide trivial linkability between individual connections, rather than just to a common server. </ins> For any algorithm, configuration agents SHOULD implement an out-of- band method to discover when servers are in danger of exhausting

Related discussion:
text: URL is probably not your intent, but that is what you get with this phrasing. I think that the point is that the values are not predictable to entities other than the one generating it. This appears in several places in the document.
Well URL uses "indistinguishable from random" :-) But OK, I'll seek a new formulation.
Code change:
Pre-Shared Key ("pre_shared_key"; pre-shared-key-extension) <del> Cookie ("cookie"; cookie) </del> Server Name Indication ("server_name"; Section 3 of RFC6066) All implementations MUST send and use these extensions when offering

Related discussion:
text: Just noticed that the MTI suites section didn't link to the suites, so here's a minor PR with some reference fiddling for this section: Add a link in MTI suites to the suites section, now that they're defined in this document. Nitpick ordering of extensions in MTI extensions to have them in same order as sections (so numbers in links are consistient). Change plaintext reference to appendices in Security Considerations to actual references.
Code change:
and a description of how common network management practices will be impacted by QUIC. <del> Since QUIC's wire image WIRE-IMAGE is integrity protected and not modifiable on path, in-network operations are not possible without terminating the QUIC connection, for instance using a back-to-back proxy.  Proxy operations are not in scope for this document.  A proxy can either explicit identify itself as providing a proxy service, or may share the TLS credentials to authenticate as the server and (in some cases) client acting as a front-facing instance for the endpoint itself. </del> <ins> Since QUIC's wire image WIRE-IMAGE is integrity-protected, in-network operations that depend on modification of data are not possible without the cooperation of an endpoint.  Network operation practices that alter data are only possible if performed as a QUIC endpoint; this might be possible with the introduction of a proxy which authenticates as an endpoint.  Proxy operations are not in scope for this document. </ins> Network management is not a one-size-fits-all endeavour: practices considered necessary or even mandatory within enterprise networks

Related discussion:
text: The point of is a little odd, because it seems to imply that ALL operations require access to the information that is integrity- or confidentiality-protected. That's clearly not the case, I think, as it is merely pointing out that if you want to modify data, then you have to be an endpoint. I think that this might be better phrased as: Note: This drops the last sentence of the original paragraph. If proxying is out of scope, then it doesn't help to talk about it so much. The point about cooperation should do.
Created a PR based on your proposed text but added some of the information about proxies to make it more clear what kind of proxies we are talking about.
Code change:
and its links. <del> Commissioning Tool (CT) is a device that assists during the installation of the network by assigning values to parameters, naming endpoints and groups, or adapting the installation to the needs of the applications. </del> <ins> Commissioning Tool (CT) is a device that assists during installation events by assigning values to parameters, naming endpoints and groups, or adapting the installation to the needs of the applications. </ins> Registrant-ep is the endpoint that is registered into the RD.  The

Related discussion:
text: Closes: URL See-Also: URL
From Benjamin Kaduk's comments: Is it? Paging NAME NAME and NAME as I honestly don't know. Trouble is: The way CTs come across in the examples, the CT goes in, does its job and leaves. But the RD's lifetimes are finite, and "Registrations in the RD are soft state and need to be periodically refreshed". So what happens when the time runs out?
A CT can indeed come in later to assist in a reconfiguration of the network/applications, e.g. adding a device, removing, or changing members of a group, or changing parameters of devices. When the CT performed a registration on behalf of an IoT device the expectation is that a very long lifetime will be picked, such that the CT doesn't have to come back to refresh. This looks problematic in case the RD state is easily lost - e.g. suppose it reboots and loses all such entries? Then there may be no CT around to send the entries to the RD again. (I would assume in this scenario that the CT's registration are more "permanent" so they would survive a reboot for example. Can be restored back from a database. In another project I work in the CT can perform such persistent registrations that survive reboots, using a special 'max' value of lifetime that signals persistent registration.)
Thanks, with that I can at least phrase an answer to the immediate question. Would it, in the deployments you describe, be conceivable that the CT is recalled on site on extraordinary events, like when the RD host is migrated to a different system or address? On the reboots, I hope that we are OK with the current situation that an RD would persist its state when it can, and administrators would not use the more volatile variety when they intend to configure long lifetimes. (If we aren't, we'd need to start thinking about negotiation of lifetimes, and that'd bring a new aspect of complexity I hope to avoid).
chrysn wrote: Hi. I thought I had commented on this somewhere already. A BRSKI-based "CT" would have a registrar which does not really leave. If we are talking about how I think that brski-async-enroll will work, then the CT will enter the no-internet-zone, do some connections, and then leave.