linux/Documentation/networking/dccp.txtより
request_retries
The number of active connection initiation retries (the number of
Requests minus one) before timing out. In addition, it also governs
the behaviour of the other, passive side: this variable also sets
the number of times DCCP repeats sending a Response when the initial
handshake does not progress from RESPOND to OPEN (i.e. when no Ack
is received after the initial Request). This value should be greater
than 0, suggested is less than 10. Analogue of tcp_syn_retries.retries1
How often a DCCP Response is retransmitted until the listening DCCP
side considers its connecting peer dead. Analogue of tcp_retries1.retries2
The number of times a general DCCP packet is retransmitted. This has
importance for retransmitted acknowledgments and feature negotiation,
data packets are never retransmitted. Analogue of tcp_retries2.
手早い話がそれぞれ、tcp_syn_retries, tcp_retries1, tcp_retries2の類似品だということ。
retries1
listenしているDCCPサイドがその接続しているpeerが死んでいると思うまで、DCCPレスポンスがどれくらい再送されるのか。
retries2
一般的なDCCPパケット再送されるときの数。これは再送されたACKやfeature negotiationに対して重要性を持っており、データパケットは再送されることはない。
