1*8447bb44SMauro Carvalho Chehab.. SPDX-License-Identifier: GPL-2.0 2*8447bb44SMauro Carvalho Chehab 3*8447bb44SMauro Carvalho Chehab====================== 4*8447bb44SMauro Carvalho ChehabDCTCP (DataCenter TCP) 5*8447bb44SMauro Carvalho Chehab====================== 6*8447bb44SMauro Carvalho Chehab 7*8447bb44SMauro Carvalho ChehabDCTCP is an enhancement to the TCP congestion control algorithm for data 8*8447bb44SMauro Carvalho Chehabcenter networks and leverages Explicit Congestion Notification (ECN) in 9*8447bb44SMauro Carvalho Chehabthe data center network to provide multi-bit feedback to the end hosts. 10*8447bb44SMauro Carvalho Chehab 11*8447bb44SMauro Carvalho ChehabTo enable it on end hosts:: 12*8447bb44SMauro Carvalho Chehab 13*8447bb44SMauro Carvalho Chehab sysctl -w net.ipv4.tcp_congestion_control=dctcp 14*8447bb44SMauro Carvalho Chehab sysctl -w net.ipv4.tcp_ecn_fallback=0 (optional) 15*8447bb44SMauro Carvalho Chehab 16*8447bb44SMauro Carvalho ChehabAll switches in the data center network running DCTCP must support ECN 17*8447bb44SMauro Carvalho Chehabmarking and be configured for marking when reaching defined switch buffer 18*8447bb44SMauro Carvalho Chehabthresholds. The default ECN marking threshold heuristic for DCTCP on 19*8447bb44SMauro Carvalho Chehabswitches is 20 packets (30KB) at 1Gbps, and 65 packets (~100KB) at 10Gbps, 20*8447bb44SMauro Carvalho Chehabbut might need further careful tweaking. 21*8447bb44SMauro Carvalho Chehab 22*8447bb44SMauro Carvalho ChehabFor more details, see below documents: 23*8447bb44SMauro Carvalho Chehab 24*8447bb44SMauro Carvalho ChehabPaper: 25*8447bb44SMauro Carvalho Chehab 26*8447bb44SMauro Carvalho ChehabThe algorithm is further described in detail in the following two 27*8447bb44SMauro Carvalho ChehabSIGCOMM/SIGMETRICS papers: 28*8447bb44SMauro Carvalho Chehab 29*8447bb44SMauro Carvalho Chehab i) Mohammad Alizadeh, Albert Greenberg, David A. Maltz, Jitendra Padhye, 30*8447bb44SMauro Carvalho Chehab Parveen Patel, Balaji Prabhakar, Sudipta Sengupta, and Murari Sridharan: 31*8447bb44SMauro Carvalho Chehab 32*8447bb44SMauro Carvalho Chehab "Data Center TCP (DCTCP)", Data Center Networks session" 33*8447bb44SMauro Carvalho Chehab 34*8447bb44SMauro Carvalho Chehab Proc. ACM SIGCOMM, New Delhi, 2010. 35*8447bb44SMauro Carvalho Chehab 36*8447bb44SMauro Carvalho Chehab http://simula.stanford.edu/~alizade/Site/DCTCP_files/dctcp-final.pdf 37*8447bb44SMauro Carvalho Chehab http://www.sigcomm.org/ccr/papers/2010/October/1851275.1851192 38*8447bb44SMauro Carvalho Chehab 39*8447bb44SMauro Carvalho Chehabii) Mohammad Alizadeh, Adel Javanmard, and Balaji Prabhakar: 40*8447bb44SMauro Carvalho Chehab 41*8447bb44SMauro Carvalho Chehab "Analysis of DCTCP: Stability, Convergence, and Fairness" 42*8447bb44SMauro Carvalho Chehab Proc. ACM SIGMETRICS, San Jose, 2011. 43*8447bb44SMauro Carvalho Chehab 44*8447bb44SMauro Carvalho Chehab http://simula.stanford.edu/~alizade/Site/DCTCP_files/dctcp_analysis-full.pdf 45*8447bb44SMauro Carvalho Chehab 46*8447bb44SMauro Carvalho ChehabIETF informational draft: 47*8447bb44SMauro Carvalho Chehab 48*8447bb44SMauro Carvalho Chehab http://tools.ietf.org/html/draft-bensley-tcpm-dctcp-00 49*8447bb44SMauro Carvalho Chehab 50*8447bb44SMauro Carvalho ChehabDCTCP site: 51*8447bb44SMauro Carvalho Chehab 52*8447bb44SMauro Carvalho Chehab http://simula.stanford.edu/~alizade/Site/DCTCP.html 53