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| author | Dimitri Staessens <dimitri@ouroboros.rocks> | 2026-07-21 06:54:55 +0200 |
|---|---|---|
| committer | Sander Vrijders <sander@ouroboros.rocks> | 2026-07-22 09:04:47 +0200 |
| commit | 3388bd9e9b82df6d7fe79fa4eee7c22a3277624e (patch) | |
| tree | 2c7d17a5d793f91b43b08d891bfc2a8bfdcef067 /include | |
| parent | 1ee9c1cfb5ecffbf4766a6c05d333dab712f4e77 (diff) | |
| download | ouroboros-3388bd9e9b82df6d7fe79fa4eee7c22a3277624e.tar.gz ouroboros-3388bd9e9b82df6d7fe79fa4eee7c22a3277624e.zip | |
The ECN marks were the only source of congestion information, and
going into congestion collapse (dropping a lot of ECN packets and
causing loss of signal) was unrecoverable.
The sender's slow-start ramp clock now tracks a measured RTT to avoid
overshooting into congestion collapse on the previously fixed (14ms)
doubling on long-delay (e.g. 100ms) links.
The flow allocator now carries a periodic heartbeat/ack to keep RTT
estimates up-to-date. The heartbeat also serves as a congestion
collapse detector: consecutive heartbeat losses will go into loss
recovery, halving the window and pausing Additive Increase until the
path is clear. The DT component now has a max_rtt config parameter that
serves as a hint for the layer RTT to optimize slow-start for
low-latency networks.
These two mechanisms follow TCP, however only during slow start up to
the first ECN signal and to recover from a total collapse until the
ECN signal returns. MB-ECN is still fully RTT-independent in the AI/PD
region. A shorter RTT path will just reach its equal fair share faster
than a longer RTT path.
Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks>
Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>
Diffstat (limited to 'include')
| -rw-r--r-- | include/ouroboros/ipcp.h | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/include/ouroboros/ipcp.h b/include/ouroboros/ipcp.h index e29b080a..135b8fcb 100644 --- a/include/ouroboros/ipcp.h +++ b/include/ouroboros/ipcp.h @@ -124,9 +124,10 @@ enum pol_cong_avoid { struct dt_config { struct { - uint8_t addr_size; - uint8_t eid_size; - uint8_t max_ttl; + uint8_t addr_size; + uint8_t eid_size; + uint8_t max_ttl; + uint16_t max_rtt; /* Declared max layer RTT (ms) */ }; struct routing_config routing; /* Routing policy */ }; @@ -135,6 +136,7 @@ static const struct dt_config default_dt_config = { .addr_size = 4, .eid_size = 8, .max_ttl = 60, + .max_rtt = 200, .routing = { .pol = ROUTING_LINK_STATE, .ls = { |