1. Tesseract A 4D Network Control Plane
Carnegie Mellon University
Microsoft Research
Rice University
Presented by: Alberto Gonzalez, Whitney Young

2. Current Designs No direct control Subtle dependencies
Example: load balance forwarding by tuning OSPF link weights, but impacts inter-domain routing

3. 4D Architecture Control plane: Decision Dissemination Discovery Data
Services:
Dissemination
Node configuration

4. Design

5. Design Goals Timely reaction to network changes
Resilient to decision plane failure
Robust and secure control channels
Minimal switch configuration
Backward compatibility
Support diverse decision algorithms
Support multiple data planes

6. Implementation Overview
Switch
Implements data plane
Decision Element (DE)
Implements discovery, dissemination, and decision planes

7. Decision Plane Any network control algorithm can be easily integrated
Incremental shortest path first
Spanning tree
Joint packet filtering/routing
Link cost-based traffic engineering
Resiliency to DE failure
Hot standbys receiving heartbeats

8. Dissemination Plane Goal: communication between DEs and switches
DEs handle most of dissemination plane, but switches help out
Path to destination handled by DE
Switches have separate queue and dissemination packets have higher priority
Security (protects switches, info passed through dissemination plane, and compromised DEs)

9. Discovery Plane Goal: minimize manual configuration
Switches send HELLO messages
DEs handle instructing the switches on what to do once active
Initiate eBGP session with outside world
Backward compatibility (bootstrapping end hosts)
Discovery plane as DHCP proxy

10. Data Plane Configured by decision plane
WriteTable exposed with simple interface to provide configuration service to decision plane
Allows easy implementation of different services
Decision/Dissemination Interface
Function independently of each other
Only 3 functions used to interface between them (2 more simply to improve performance)

11. Performance Evaluation
Single Link Failures
Switch& Regional Failures
Link Flapping
10-hop to 12-hop change
Tesseract can handle network changes

12. Performance Evaluation
1347 nodes & 6244 edges
DE Computation Time
Worst Case: 151ms
99th percentile: 40ms
Bandwidth overhead
Worst Case: 4.4MB
90% of switched updated with new state

13. Performance Evaluation
Failover times

14. Applications In enterprise network:
Computers both new routes & packet filter placements
Loads into routers with no forbidden traffic leaked
No human involvement once security policy is specified

15. Ethernet Key features Tesseract keeps these properties.
Widely implemented frame format
Support for broadcasting frames
Transparent address learning model
Tesseract keeps these properties.

16. Ethernet Through point comparisons Control Plane for TCP flows
Started at 570Mbps
Leveled at 280Mbps after a failure
Conventional RSTP Control Plane
Starts at 280Mbps
Hit zero after failure
Recovered after 7-8 seconds at ~180Mbps

17. Summary Tesseract Robust Secure Resuable Good Performance Scalable
Decission/Dissemination Planes
Secure
Enterprise Network
Resuable
Ethernet or IP
Good Performance
Convergence & Throughput
Scalable
1,000+ Switches
Enables direct Control
Easier to Understand and Deploy