Data  Center  Networking  in  the  Era  of  Overlays  

Mar8n  Casado  Nicira  Networks  

casado@nicira.com      

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Trend:    From  Micro  to  Macro  

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Trend:    The  Resource  Pool  

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Compute   Storage   Network  

• Run any desired workload • Anywhere • Over any hardware • (… and do it quickly and efficiently)

Run any desired workload • Anywhere • Over any hardware • (… and do it quickly and efficiently)

The  Problem:    “Networking  in  the  Way”  

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Isolation

Security

SLAs Over subscription

VLANs VLANs

VLANs VLANs

ACLs

ACLs

ACLs QoS QoS

QoS

Service Routing

A  (Popular)  SoluCon:  Overlay  

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•  Consume  a  lot  of  funcCons  from  the  network  •  IsolaCon,  Mobility,  Load  distribuCon,  Security  

QoS,  AccounCng  •  In  wide  use  today    •  hZp,  distributed  compute  harness,  virtual  network  

overlay  

Arguments  for  the  Overlay  (a  lot  like  SDN)  

•  FuncConality  is  implemented  in  so[ware  •  Allows  the  use  of  simple/cheap  network  fabric  •  Decoupled  operaCons  from  proprietary  interfaces  •  Natural  way  of  integraCng  L4-­‐L7  control  •  O[en  can  avoid  high-­‐levels  of  aggregaCon    

(reduce  pressure  on  hardware  tables)  •  Take  advantage  of  edge  semanCcs  

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So  ..  Where  Does  SDN  Fit?  

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My  view:  compaCble,  not  necessarily  compeCCve  (SDN  won’t  replace  overlay,  overlay  won’t  replace  SDN)  

So  ..  Where  Does  SDN  Fit?  

Pod Pod Pod Pod MarCn  Casado,  2/8/12   8  

Create  the  fabric  

Control  the  overlay  

SDN  and  the  Fabric  

Pod Pod Pod Pod

OF   OF  

OF   OF  

OF   OF   OF   OF  

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Control  Plane  •  Probably  have  to  push  all  state  proac5vely  •  Mul5pathing  requires  state  replica5on  •  Likely  des5na5on-­‐only  w/  aggrega5on  •  End  up  implemen5ng  L3  w/  extra  control  channel  

SDN  and  the  Fabric  

•  SDN  not  obvious  fit  for  fabric  control  plane    (for  large  deployments)        

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•  SDN  great  for  fabric  config  (OAM)  •  And  one  I  know  the  config  group  is  keen  to  tackle  

SDN  to  Control  the  Overlay  

Controller Cluster

Pod Pod Pod

Tunnels GRE, CAPWAP, STT, VXLAN

MarCn  Casado,  2/8/12   11  Pod Pod

SDN  and  the  Overlay  

•  Standardize  OpenFlow  as  control  interface  to  overlays  (VXLAN,  NVGRE,  STT,  etc.)  •  Manage  tunnels  •  Map  packets  to  tunnels  •  Manage  forwarding  state  within  the  overlay    

(QoS,  filtering,  accounCng,  etc.)    •  Consider  creaCng  “so[  switch”  friendly  extensions  to  

OpenFlow    

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Extending  SDN  for  Fabric  

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Fabric  Interface  

• Acknowledge decoupled control problems • Simplify fabric forwarding model • Standardize fabric service model

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And  Now  …  A  TangenCally  Related  Announcement  

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hZp://openvswitch.org