PortLand: A Scalable Fault- Tolerant Layer 2 Data Center Network Fabric B 財金三 婁瀚升 1

Outline Introduction Background Design Implementation Conclusion 2

Introduction LAN insufficiency Requirement Network in datacenter : – VM Migration without IP change – Needn’t config switch before deployment – Host in datacenter efficiently communicate – No forwarding loop – Fault-tolerant and recovery 3

Introduction Layer 2 kind fabric – Layer 3 not workable VM migration with IP change Config switches of subnet and DHCP synchronite TTL method: prevent forwarding loop Prevent routing broadcast 4

Background:DatacenterNetwork Topology Forwarding – Layer 3 : IP assigned hierachically Broadcast (Failure avoidance, overhead ) Config switch subnet & DHCP syncro. Fault VM migration unable – Layer 2 : MAC Single spanning tree problem (not shortest way) Broadcast entire fabric – VLAN : Source pre-assignment (decrease flex. & scal.) Switch need to maintain VLAN’s state 5

End host Virtualization – Layer 3 setting : not work – ARP to solute ? Background:DatacenterNetwork 6

Fat Tree Network Multi-rooted Stage : edge, aggregation, core K-port swithes: – k 3 /4 end hosts – 5k 2 /4 individual k-port switches – k individual pods – each pod : k 2 /4 hosts 7

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Design : Fabric Manager Centralized Manager Fuction : – Mantain soft state network config (ex.topology) – Responsible for ARP resolution Fault tolerance Multi-cast Only soft state (no hard state, ex.#of switch) 9

Design : Pseudo MAC Assigned to end hosts Information include: – Location : same pod, same prefix – Pod number→ position numer End host with their own AMAC LDP (location discovery protocol) – employed to assign – Pod.position.port.vmid 10

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Design : Proxy-based ARP Ethernet : B-cast to all host(same layer2) Used for communication in datacenter If FM not available for IP-PMAC mapping →bcat to core(O(k) state ) VM migration supporting – FM sending invalidation message to old pos. – If contact with this message → new PMAC address in the host’s cache 12

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Design : Distributed Location Discovery Location Discovery Protocol (LDP) No administative config (no manul set) Location Discovery Message: – Sent by switches – Several information – Edge got from aggregation, learned →Aggregation learned →Core learned 14

Design : Distributed Location Discovery Location Discovery Message: – Position number acquisition: Randomly chosen number Verified by aggregation – Pod number acquisition: FM assignment to aggregation – Exception : non-existence LDM not correct Disable suspicious port 15

Design:Loop free Forwarding Prevent using Spanning tree Downward seperate from Upward 16

Design : Fault Tolerance Unicast Fault Detection and Action Multicast Fault Detection and Action 17

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Deisign : Comparison 21

Implementation : System 22

Implementation :Evaluation 23

Implementation :Evaluation 24

Implementation :Evaluation 25

Implementation :Evaluation 26

Implementation :Evaluation 27

Implementation :Evaluation 28

Conclusion Commercial Use Datacenter Network Protocol 29