J. K. Kim

Portland

Trend of Data Center

By J. Nicholas Hoover , InformationWeek June 17, 2008 04:00 AM

200 million Euro

Data centers will be larger and larger in the future cloud computing era to benefit from commodities of scale. Tens of thousand Hundreds of thousands in # of servers

Most important things in data center management- Commodities of scale- Keep High utilization of their expensive equipment- Maximize revenue- Saving administration cost- Low power consumption (http://www.energystar.gov/ia/partners/prod_development/downloads/EPA_Datacenter_Report_Congress_Final1.pdf)

http://gigaom.com/cloud/google-builds-megadata-center-in-finland/

http://www.datacenterknowledge.com

Requirements for future data centerTo catch up with the trend of mega data center, DCN technology

should meet the requirements as belowHigh ScalabilityTransparent VM migration (high agility)Easy deployment requiring less human administrationEfficient communicationLoop free forwardingFault Tolerant

• Current DCN technology can’t meet the requirements.Layer 3 protocol can not support the transparent VM migration.Current Layer 2 protocol is not scalable due to the size of forwarding table

and native broadcasting for address resolution.

Overall Idea of PortLandAdd a new host

Transfer a packet

Key features - Layer 2 protocol based on tree topology - PMAC encode the position information - Data forwarding proceeds based on PMAC- Edge switch’s responsible for mapping between PMAC and AMAC- Fabric manger’s responsible for address resolution- Edge switch makes PMAC invisible to end host- Each switch node can identify its position by itself- Fabric manager keep information of overall topology. Corresponding to the fault, it notifies affected nodes.

Questions in discussion boardQuestion about Fabric Manager

o How to make Fabric Manager robust ?o How to build scalable Fabric Manager ?

Redundant deployment or cluster Fabric manager could be solution

Question about reality of base-line tree topologyo Is the tree topology common in real world ?

Yes, multi-rooted tree topology has been a traditional topology in data center.

[A scalable, commodity data center network architecture Mohammad La-Fares and et el, SIGCOMM ‘08]

Discussion pointso Is the PortLand applicable to other topology ?

The Idea of central ARP management could be applicable. To solve forwarding loop problem, TRILL header-like method would be necessary. The benefits of PMAC ? It would require larger size of forwarding table.

Question about benefits from VM migrationo VM migration helps to reduce traffic going through aggregate/core switches.o How about user requirement change?o How about power consumption ?

ETCo Feasibility to mimic PortLand on layer 3 protocol.

o How about using pseudo IP ?

o Delay to boot up whole data center