Download - Zdravko Bozakov
Towards Virtual Routers as a Service
6th GI/ITG KuVS Workshop on “Future Internet”November 22, 2010
Hannover
Zdravko Bozakov
Towards Virtual Routers as a Service
Talk outline Virtualization overview Use case: virtual routers as a service Problem statement Resource allocation algorithm Virtual router location selection In brief
Virtual router architecture Live-migration
Summary and outlook
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Network Virtualization Overview
Virtualization aims to decouple logical and physical network resources and increase network flexibility
Variable mapping of physical and logical entities Slice network hardware for multiple customers Handle multiple network devices using a single control plane
Live-migration of logical routers Load balancing (capacity, routing tables, CPU) Scheduled router maintenance Energy conservation
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Virtual Routers as a Service
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Virtual Routers as a Service
On-demand provision of connectivity over core network Enterprise branch offices Regional providers University campuses
Single virtual router for edge interconnection Reduction of customer management overhead Consolidation of provider resources and transparent remapping
Port relay nodes (PRN) Forward traffic to virtual router (root node)
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Problem Statement
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What we have: Backbone network
Weighted graph G with weights W Link utilization U and capacity C (u/c)
Customer requirements Subset of edge nodes Γ Capacity demand D for
edge nodes γ
What we need: Optimal location of VR root node R Optimal paths from R to Γ satisfying
capacity constraints
W=1
R
Path Selection Algorithm
Trivial case: unlimited backbone capacity For each γ calculate shortest path to R (e.g. Dijkstra)
Does not work for capacity constrained networks
Solution with constraints: flow network theory (successive shortest paths)
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SRC DST
w=0C=1
w=0C=4
Root Node Selection
Optimal location of root node R Minimize the cost S of bandwidth consumed by the VR links V
Root selection using total enumeration Nodes with insufficient resources are pruned (e.g. capacity, CPU, memory)
Example: optimal root node locations with total cost S=4
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Virtual Router Architecture
Root node: hardware accelerated virtual router Control plane virtualization
using standard VMson commodity servers
Programmable data plane using Openflow-enabled switches
Port relay nodes (PRN) Forward packets based
on L2 virtual router addresses along computed paths
Openflow implementation
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Live Router Migration
Virtual router architecture allows live router migration Setup outbound PRN paths for new root node R* Clone forwarding table from old root R and remap physical ports Control plane continuously updates routing tables on R and R* Asynchronously setup inbound paths for R* Tear down old paths and root node
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Watch the demo during the break!
Conclusion and Outlook
Conclusion On-demand connectivity using single logical router instance
reduces management overhead Presented approach allows optimal computation of paths to a router
located within network core Basic root node selection strategy Architecture is capable of live-migration
Outlook Refine path selection algorithm and analyze alternative approaches Optimize root node selection method Detailed evaluation of live-migration performance Implement and evaluate fallback strategies
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