diff options
| author | Samuel Jero <sj323707@ohio.edu> | 2011-07-24 20:49:19 -0600 |
|---|---|---|
| committer | Gerrit Renker <gerrit@erg.abdn.ac.uk> | 2011-08-01 07:52:35 -0600 |
| commit | d346d886a4c7f771c184e73833133f23a18de884 (patch) | |
| tree | b30d5ea65d37af5dd49f03712ae2f973bc71553b /net/dccp/ccids/ccid2.h | |
| parent | 31daf0393fbb17cf6efe613fb538a3ea4b5202e4 (diff) | |
| download | linux-d346d886a4c7f771c184e73833133f23a18de884.tar.bz2 | |
dccp ccid-2: prevent cwnd > Sequence Window
Add a check to prevent CCID-2 from increasing the cwnd greater than the
Sequence Window.
When the congestion window becomes bigger than the Sequence Window, CCID-2
will attempt to keep more data in the network than the DCCP Sequence Window
code considers possible. This results in the Sequence Window code issuing
a Sync, thereby inducing needless overhead. Further, if this occurs at the
sender, CCID-2 will never detect the problem because the Acks it receives
will indicate no losses. I have seen this cause a drop of 1/3rd in throughput
for a connection.
Also add code to adjust the Sequence Window to be about 5 times the number of
packets in the network (RFC 4340, 7.5.2) and to adjust the Ack Ratio so that
the remote Sequence Window will hold about 5 times the number of packets in
the network. This allows the congestion window to increase correctly without
being limited by the Sequence Window.
Signed-off-by: Samuel Jero <sj323707@ohio.edu>
Acked-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Diffstat (limited to 'net/dccp/ccids/ccid2.h')
| -rw-r--r-- | net/dccp/ccids/ccid2.h | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/net/dccp/ccids/ccid2.h b/net/dccp/ccids/ccid2.h index f585d330e1e5..18c97543e522 100644 --- a/net/dccp/ccids/ccid2.h +++ b/net/dccp/ccids/ccid2.h @@ -43,6 +43,12 @@ struct ccid2_seq { #define CCID2_SEQBUF_LEN 1024 #define CCID2_SEQBUF_MAX 128 +/* + * Multiple of congestion window to keep the sequence window at + * (RFC 4340 7.5.2) + */ +#define CCID2_WIN_CHANGE_FACTOR 5 + /** * struct ccid2_hc_tx_sock - CCID2 TX half connection * @tx_{cwnd,ssthresh,pipe}: as per RFC 4341, section 5 |