Portland

J. K. Kim

Trend of Data Center

By

J. Nicholas Hoover

, InformationWeek June 17, 2008 04:00 AM http://gigaom.com/cloud/google-builds-megadata-center-in-finland/

200 million Euro

http://www.datacenterknowledge.com

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)

Requirements for future data center

 To catch up with the trend of mega data center, DCN technology should meet the requirements as below     High Scalability Transparent VM migration (high agility) Easy deployment requiring less human administration Efficient communication   Loop free forwarding Fault 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 PortLand

Add a new host

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.

Transfer a packet

Questions in discussion board

 Question about Fabric Manager o o How to make Fabric Manager robust ?

How to build scalable Fabric Manager ?

 Redundant deployment or cluster Fabric manager could be solution  Question about reality of base-line tree topology o 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 points

o 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 migration o VM migration helps to reduce traffic going through aggregate/core switches.

o o How about user requirement change?

How about power consumption ?

 ETC o o Feasibility to mimic PortLand on layer 3 protocol.

o How about using pseudo IP ?

Delay to boot up whole data center