Differentiated Congestion Management of Data Traffic for Data center Ethernet B 資管三 陳育旋

author Shuo Fang, Student Member, IEEE, Chuan Heng Foh, Senior Member, IEEE, and Khin Mi Mi Aung, Senior Member, IEEE

Introduction Fibre Channel over Ethernet (FCoE) -- use Ethernet technology to carry Fibre Channel -- Fibre Channel are encapsulated in Ethernet to be transmitted FCoE has some benefit -- reduce power consumption for I/O operation -- eliminate redundancy in the network -- I/O consolidation among Local Area Networks(LANs) and Storage Area Networks(SANs)

SANs (reference) Storage Area Networks 將許多儲存裝置從區域網路獨立出來成為 另一個網路 透過光纖通道﹙ Fibre Channel ﹚與伺服主 機做連結 具備快速備份與災難復原能力 但成本較高、且建置費時

However…. -- Fibre Channel (FC) is designed to achieve high speed lossless packet transportation -- Ethernet has no control on the traffic congestion Introduction How to consolidate? Differentiated congestion control in Ethernet!

outline Introduction Ethernet Congestion Management Differentiated Congestion Control Analysis (experiment) conclusion

outline Introduction Ethernet Congestion Management Differentiated Congestion Control Analysis (experiment) conclusion

Ethernet Congestion Management Implementing a particular ECN at switches and rate limiter at host

Ethernet Congestion Management Q off is the offset of the current buffer utilization with respect to Q eq (+ or - ) Q delta is the change in length of the queue since the last sampled frame

In ECM, each rate limiter implements a variation of AIMD for its rate adjustment. A rate limiter periodically increase its sending rate Fb = feedback signal Ethernet Congestion Management

outline Introduction Ethernet Congestion Management Differentiated Congestion Control Analysis (experiment) conclusion

Differentiated Congestion Control we propose using different AIMD parameter sets for the rate limiters to achieve congestion control differentiation

Queue Management in Congestion Point Rate Limiters in the Reaction Point Differentiated Congestion Control

Queue Management in Congestion Point Rate Limiters in the Reaction Point Differentiated Congestion Control

A congestion point (CP) features a queue management which is mainly responsible for congestion detection, congestion, notification and packet drop policy. when the buffer utilization exceeds T sc, all LAN traffic, being the low priority traffic, will be dropped. Queue Management in Congestion Point

Rate Limiters in the Reaction Point Differentiated Congestion Control

Rate Limiters in the Reaction Point A rate limiter regulates the traffic flow by controlling the transmission rate using an AIMD based rate adjustment operation the rate limiter maintains a variable called congestion window to regulate the transmission rate

The value of congestion window is initialized to be one. This value increases linearly over a predefined constant time interval called a slot. Rate Limiters in the Reaction Point

outline Introduction Ethernet Congestion Management Differentiated Congestion Control Analysis (experiment) conclusion

Analysis(experiment) Background traffic SAN (a1,b1) LAN (a2,b2) destination Buffer (bottleneck)

Analysis(experiment) Performance comparison with various schemes Protections with presence of misbehaved hosts Bandwidth utilization differentiation Setting of marking probabilities A case study of multiple types of traffic

Analysis(experiment) Performance comparison with various schemes Protections with presence of misbehaved hosts Bandwidth utilization differentiation Setting of marking probabilities A case study of multiple types of traffic

Performance comparison with various schemes to investigate the effectiveness and system stability of our congestion control

Analysis(experiment) Performance comparison with various schemes Protections with presence of misbehaved hosts Bandwidth utilization differentiation Setting of marking probabilities A case study of multiple types of traffic

Protections with presence of misbehaved hosts we consider the situation where LAN sources do not regulate their rates based on the notification instructions

Analysis(experiment) Performance comparison with various schemes Protections with presence of misbehaved hosts Bandwidth utilization differentiation Setting of marking probabilities A case study of multiple types of traffic

we analyze the bandwidth differentiation feature of our proposed system Bandwidth utilization differentiation

Analysis(experiment) Performance comparison with various schemes Protections with presence of misbehaved hosts Bandwidth utilization differentiation Setting of marking probabilities A case study of multiple types of traffic

Setting of marking probabilities Although setting a higher marking probability can ensure a stable buffer level around equilibrium threshold as well, this is unnecessary due to the more overhead it may introduce

Setting of marking probabilities

Analysis(experiment) Performance comparison with various schemes Protections with presence of misbehaved hosts Bandwidth utilization differentiation Setting of marking probabilities A case study of multiple types of traffic

Our scenario deals with uploading of files from clients and a total of three types of traffic are involved A case study of multiple types of traffic

1.Client1 and Client2 first connect to ApplicationServer1 sending upload requests of LAN traffic type, and this traffic is light. 2. On reception of any request, Application Server1 connects to Metadata Server for data index

3.&3.5 MetadataServer replies with index to identify and track data storage locations. Traffic load between ApplicationServer1 and MetadataServer can be high 4. After index being obtained, Client1 and Client2 connect to the storage directly for file writing, which is SAN traffic # HPCServer1 communicates with HPC Server2 with Inter Process Computing (IPC) traffic A case study of multiple types of traffic

Lowest priority : LAN Higher priority : SAN Highest priority : IPC We adopt a target bandwidth utilization ratio of 1:1.4:1.8 for W1:W2:W3 where W1:W2:W3 describe bandwidth utilization for LAN, SAN and IPC traffic.

A case study of multiple types of traffic

outline Introduction Ethernet Congestion Management Differentiated Congestion Control Analysis (experiment) conclusion

Our proposed method considered using different AIMD settings for the rate limiter operations and took protection of high priority traffic into account to regulate malicious parties