Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

Disabling Spin bit for what percentage of connections? #3270

Closed
wants to merge 1 commit into from
Closed

Disabling Spin bit for what percentage of connections? #3270

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Jump to
Jump to file
Failed to load files.
Diff view
Diff view
9 changes: 4 additions & 5 deletions draft-ietf-quic-transport.md
View file
Open in desktop
Expand Up @@ -4331,11 +4331,10 @@ Each endpoint unilaterally decides if the spin bit is enabled or disabled for a
connection. Implementations MUST allow administrators of clients and servers
to disable the spin bit either globally or on a per-connection basis. Even when
the spin bit is not disabled by the administrator, implementations MUST disable
the spin bit for a given connection with a certain likelihood. The random
selection process SHOULD be designed such that on average the spin bit is
disabled for at least one eighth of network paths. The selection process
performed at the beginning of the connection SHOULD be applied for all paths
used by the connection.
the spin bit for at least a sixteenth of connections with an expectation that
the spin bit is disabled for at least one eighth of network paths. The selection
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

endpoints MUST disable their use of the spin bit on at least one in every 16 network paths, or for one in every 16 connection IDs. This ensures that the spin bit signal is disabled on approximately one in eight network paths.

Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

@martinthomson If we are to "ensure" that the spin bit signal would be disabled for approx. 1/8 of network paths, I think we need to require endpoints to select one in every 16 paths at random. Otherwise, the paths that would have the spin bit disabled could go below 1/8. For example, when there is only one client and one server talking to each other, and if both of them disable spin bit for every 16th connection they handle, then the spin bit would be enabled for only 1/16 of all the connections.

Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Quite right.

endpoints MUST disable their use of the spin bit for a random selection of at least one in every 16 network paths, or for one in every 16 connection IDs. This ensures that the spin bit signal is disabled on approximately one in eight network paths.

process performed at the beginning of the connection SHOULD be applied for all
paths used by the connection.
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

In reviewing this last sentence, I am reminded that this provides a nice signal that might improve linkability. I think that the requirement to perform the determination separately for every network path/connection ID as suggested above is better.


When the spin bit is disabled, endpoints MAY set the spin bit to any value, and
MUST ignore any incoming value. It is RECOMMENDED that endpoints set the spin
Expand Down