linkagg

Example implementation of link agreggation hashing algorithm. This is in response to Christopher Hart's (@_ChrisJHart) post here. This is by no means exhaustive or bug-free, it's just a fun side-project to explore hashing algorithms and Ethernet link load-balancing.

Installation

1. Make sure you have gcc installed (Ubuntu): sudo apt update && sudo apt install build-essential
2. Make sure you have Python 3.9.7 installed: Pyenv
3. Clone the repo and cd into the directory: git clone https://github.com/clay584/linkagg.git && cd linkagg
4. Create a Python virtual environment: python -m venv venv
5. Activate the Python virtual environment: source venv/bin/activate
6. Install the Python dependencies: pip install -r requirements-dev.txt
7. Compile the cythonized code: python setup.py build_ext --inplace

Usage

./demo.py <number_of_active_links> <num_of_unique_flows_to_generate>

OR

python -m linkagg <number_of_active_links> <num_of_unique_flows_to_generate>

Example Output

Running 8,000 frames through with an eight interface bundle.

❯ ./demo.py 8 8000
One frame for every flow only. We should see a uniform distribution
==================================================
Egress Queue 1: 984 frames
Egress Queue 2: 978 frames
Egress Queue 3: 1025 frames
Egress Queue 4: 980 frames
Egress Queue 5: 1015 frames
Egress Queue 6: 1065 frames
Egress Queue 7: 988 frames
Egress Queue 8: 965 frames
==================================================

Now lets see it with two elephant flows. Sometimes those will hit the same interface
==================================================
Egress Queue 1: 984 frames
Egress Queue 2: 978 frames
Egress Queue 3: 11025 frames
Egress Queue 4: 980 frames
Egress Queue 5: 1015 frames
Egress Queue 6: 1065 frames
Egress Queue 7: 988 frames
Egress Queue 8: 10965 frames
==================================================
Total hashing time: 32.13191032409668 ms

Tests

How can we ensure we get it right? With tests of course! (I'm not saying there are no bugs. I'm sure there are bugs.)

First, install the dev requirements: pip install -r requirements-dev.txt

Run pytest -v

❯ pytest -v
=========================== test session starts ===========================
platform linux -- Python 3.9.7, pytest-6.2.5, py-1.10.0,
pluggy-1.0.0 -- /home/jccurtis/code/personal/linkagg-hash/venv/bin/python
cachedir: .pytest_cache
rootdir: /home/jccurtis/code/personal/linkagg-hash
collected 5 items

tests/test_linkagg.py::test_version PASSED                    [ 20%]
tests/test_linkagg.py::test_frames PASSED                     [ 40%]
tests/test_linkagg.py::test_one_intf PASSED                   [ 60%]
tests/test_linkagg.py::test_link_distribution PASSED          [ 80%]
tests/test_linkagg.py::test_hashes_are_deterministic PASSED   [100%]

============================ 5 passed in 0.37s ============================