OSPF Offloading: The HELLO Protocol A First Step Toward Distributed Heterogeneous Offloading Speaker: Mary Bond

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

The Future of Network Forwarding Devices

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

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

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

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

Interface and Neighbor Finite State Machines

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

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

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

Offloaded OSPF, IXP Architecture

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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