I think your question is same to "MSS and MTU" #592 on quicwg. - MSS and MTU https://github.com/quicwg/base-drafts/issues/592
- Masaori 2017年11月9日(木) 21:17 Chao Xu <ok...@apache.org>: > Hi Masaori , Maskit , Scw00 > > Is it a RFC mistake ? > > The max size of QUIC Packet is 1280 but the default MSS for loose > detection is 1460. > > According to > https://quicwg.github.io/base-drafts/draft-ietf-quic-transport.html#rfc.section.9 > > ``` > 9. > <https://quicwg.github.io/base-drafts/draft-ietf-quic-transport.html#rfc.section.9> > Packetization and Reliability > <https://quicwg.github.io/base-drafts/draft-ietf-quic-transport.html#packetization> > > ... > > In the absence of these mechanisms, QUIC endpoints SHOULD NOT send IP > packets larger than 1280 octets. Assuming the minimum IP header size, > this results in a QUIC packet size of 1232 octets for IPv6 and 1252 octets > for IPv4. > > QUIC endpoints that implement any kind of PMTU discovery SHOULD maintain > an estimate for each combination of local and remote IP addresses (as each > pairing could have a different maximum MTU in the path). > > QUIC depends on the network path supporting a MTU of at least 1280 octets. > This is the IPv6 minimum and therefore also supported by most modern IPv4 > networks. An endpoint MUST NOT reduce their MTU below this number, even if > it receives signals that indicate a smaller limit might exist. > ``` > > And the > https://quicwg.github.io/base-drafts/draft-ietf-quic-recovery.html#rfc.section.4.7.1 > > ``` > 4.7.1. > <https://quicwg.github.io/base-drafts/draft-ietf-quic-recovery.html#rfc.section.4.7.1> > Constants of interest > <https://quicwg.github.io/base-drafts/draft-ietf-quic-recovery.html#constants-of-interest-1> > > Constants used in congestion control are based on a combination of RFCs, > papers, and common practice. Some may need to be changed or negotiated in > order to better suit a variety of environments. > > kDefaultMss (default 1460 bytes):The default max packet size used for > calculating default and minimum congestion windows.kInitialWindow > (default 10 * kDefaultMss):Default limit on the amount of outstanding > data in bytes.kMinimumWindow (default 2 * kDefaultMss):Default minimum > congestion window.kLossReductionFactor (default 0.5):Reduction in > congestion window when a new loss event is detected. > ``` > > > Oknet >
