OSPF Offloading: The HELLO Protocol

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OSPF Offloading The HELLO Protocol

• A First Step Toward Distributed Heterogeneous
  Offloading
• Speaker Mary Bond

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Introduction The Challenge

• Traditional IP router architecture incorporates
  single centralized control processor
• Scalability issues are real
• Large amount of I/O bandwidth required across
  backplane

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The Future of Network Forwarding Devices
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The Protocol Offload Solution Long Term Goal

• Distribute functionality by protocol offloading
  to forwarding plane blades
• Design a generalized framework for offloading
  protocols
• The Approach
• Examine offloading possibilities of many routing
  protocols
• Use collective results to design offloading
  framework

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OSPF A Brief Overview

• Link state vector algorithm
• Distribute data by flooding
• Amount of data passed reduced via area grouping
• External data advertised, separate from link
  state data

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OSPF A Brief Overview

• HELLO packets used to acquire neighbors
• HELLO protocol elects designated router
• Link state ads (LSAs) reflect adjacencies
• LSAs flooded reliably
• Link state database is collection of LSAs from
  every router in area

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OSPF Offloading The HELLO Protocol

• Two primary OSPF data structures
• Interfaces
• Neighbors
• Interface algorithms
• HELLO
• Designated Router Election
• Neighbor algorithms
• Database Distribution
• Link State Updates
• Routing Table Calculation

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Interface and NeighborFinite State Machines
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Communication Between GOSPF and OOSPF

• Synchronizing Data Structure Fields
• Starting/Stopping HELLO Timers
• Instigating FSM Transitions
• Triggering Link State Advertisements
• Updating Designated Router (or Backup)
• Instigating sending of HELLO Packets

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GOSPF and OOSPF Proxies

• GOSPF and OOSPF communicate via proxies
• Remote procedure calls are transparent
• TCP connection

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The RPC Class

• Provides general framework for communication
  between proxies
• Child classes inherit from RPC class, one for
  each remote procedure call
• Child classes correspond to specific functions
  (called remotely) between GOSPF and OOSPF

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Offloaded OSPF, IXP Architecture
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Conclusions

• Future control plane processing presents a
  bottleneck issue
• Protocol offloading is a possible solution
• This project was a first step toward studying the
  offloading of control plane routing protocols.

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Thank you!