SEL Communications Network Design
|SEL Communications Network Design|
|Duration:||Spring 2015 - Fall 2015|
|Faculty Advisor:||Feng Li|
This senior design project will (1) determine methods for testing network performance, (2) increase network performance by utilizing SEL-2730M features & network topologies, and (3) share our discoveries with future UI students by compiling 3 lab experiments that teach what we’ve discovered in our efforts to improve Ethernet communication network reliability and performance.
- 1 Project Timeline
- 2 Project Definition
- 3 Project Learning
- 4 Team Information
- 5 Document Archive
Stage 1 | Project Learning | Jan. 15th – March 1st
- Project Understanding
- Evaluate Deliverables
- Determining Specifications
Stage 2 | System Design | March 1st – April 15th
- Establish fully-functioning substation network with firewall.
- Attain additional hardware: 4 SEL-2730Ms (Managed Switch) & 1 SEL-3620 (Gateway)
Stage 3 | Determine Base Performance Characteristics | April 15th – Aug. 15th
- Determine top 5 important network performance metrics.
- Evaluate current system ‘base’ performance.
- Study other networks and learn about their average performance.
Stage 4 | Performance Study | Aug. 15th – Nov. 1st
- What impacts communication performance?
- What are the weaknesses in cyber security?
Stage 5 | System Optimization | Nov. 1st – Dec. 18th
- Optimize communication network from what was discovered in Stage 4.
- Document all settings/configuration/performance results
Stage 6 | Lab Experiments Design | Nov. 1st – Dec. 18th
- Compile 3 labs that teach students how to design and configure robust and secure substation communication networks.
|Initial Timeline||Actual Timeline|
- SEL is looking to advance the speeds and reliability of their Ethernet communication network technology. In addition to this, SEL hopes to teach future Electrical and Computer Engineering students the methods in which to configure a communication network to achieve a high level of performance.
- Documented, repeatable network relay settings/configurations.
- Documented process for testing network reliability, speed, and overall performance.
- Performance Comparisons with multiple substation network configurations.
- Record of testing procedure's steps, difficulty, and setup time.
- 3 Lab Experiments teaching fundamental relay configurations.
- Client Status Report: biweekly email update and monthly phone meeting.
- In order to achieve a high-quality product outcome, our group will continually communicate with our client (SEL) as the project specifications evolve.
- Project Specifications
- 100% Data packets received
- Maintain a low data latency to achieve required protection trip times to secure infrastructure & life.
- Cyber-Secure Network
- Ethernet Network
- Increase data transfer speeds compared to normal (base) network configurations
- RSTP 'Rapid Spanning Tree Protocol'
- Minimize STP 'tree convergence' times
The STP algorithm calculates the new ‘spanning tree’ topology with the following steps:
- The ‘root bridge’ is selected based on the smallest ‘bridge ID.’
- A bridge is a switch (SEL-2730M).
- Bridge ID = bridge priority + MAC
- The bridge priority can be configured on the SEL-2730M web-based GUI.
- ‘Least-Cost-Paths’ are determined from each switch to ‘root bridge.’
- Each switch possibly has multiple paths to the root bridge.
- Each path has a ‘cost’ associated with the band-width of each segment between the bridge & the ‘root bridge.’
- From these paths, it picks the smallest cost path.
- Least cost path from bridge to ‘root bridge’ is selected.
- All other root paths are disabled.
Network Performance Metrics
- packet loss - measured with ping command
- throughput - measured with ostinato
- max latency - measured with ping command
- avg latency - measured with ping command
- jitter - measured with ping command
- spanning tree convergence time - measured with a special ping method using one ping/ms and counting dropped pings to calculate convergence time to the ms
Simulating Network Congestion
Using ostinato on multiple headless Raspberry Pi's it was possible to load the network with meaningless dummy data packets when no filtering was being used in the managed switches.
Increasing Cyber Security
- Use rate-limiting on port to gateway.
- All outside traffic goes through gateway.
- Disable all ports not being used.
- Use the features the SEL-2730M has to offer (MAC based port security).
- Update IED access passwords regularly.
- Change passwords after employee leaves.
- Make the network physically hard to access: rear side of relays inaccessible, tamper-proof screws.
Discovered Solutions for Improving Network Performance
The less switches, the better the system performs. Each switch you add to a communication network adds latency since the data has to stop there, wait it’s turn to be process, then sent along.
SEL-2730M Managed Ethernet Switch Features
- Multicast MAC Filtering
- Port Mirroring
- Rate Limiting
- MAC Based Port Security
- Team Meeting Minutes
- Lab Procedures
- Miscellaneous Configuration Documents