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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 /src/lib | |
| 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 'src/lib')
| -rw-r--r-- | src/lib/pb/ipcp_config.proto | 1 | ||||
| -rw-r--r-- | src/lib/protobuf.c | 3 |
2 files changed, 4 insertions, 0 deletions
diff --git a/src/lib/pb/ipcp_config.proto b/src/lib/pb/ipcp_config.proto index eac4da37..a111b6d8 100644 --- a/src/lib/pb/ipcp_config.proto +++ b/src/lib/pb/ipcp_config.proto @@ -42,6 +42,7 @@ message dt_config_msg { required uint32 eid_size = 2; required uint32 max_ttl = 3; required routing_config_msg routing = 4; + optional uint32 max_rtt = 5; } message dir_dht_config_msg { diff --git a/src/lib/protobuf.c b/src/lib/protobuf.c index a824d357..6beae000 100644 --- a/src/lib/protobuf.c +++ b/src/lib/protobuf.c @@ -362,6 +362,8 @@ dt_config_msg_t * dt_config_s_to_msg(const struct dt_config * s) msg->addr_size = s->addr_size; msg->eid_size = s->eid_size; msg->max_ttl = s->max_ttl; + msg->has_max_rtt = true; + msg->max_rtt = s->max_rtt; msg->routing = routing_config_s_to_msg(&s->routing); if (msg->routing == NULL) goto fail_routing; @@ -381,6 +383,7 @@ struct dt_config dt_config_msg_to_s(const dt_config_msg_t * msg) s.addr_size = msg->addr_size; s.eid_size = msg->eid_size; s.max_ttl = msg->max_ttl; + s.max_rtt = msg->has_max_rtt ? msg->max_rtt : 200; /* ms */ s.routing = routing_config_msg_to_s(msg->routing); return s; |