# BGP Flowspec

BGP Flowspec is an extension of BGP designed to allow the creation and propagation of detailed traffic flow filtering rules. These rules can be applied across different ASs .

The following table shows the available components to select a flow: After you have specified a particular flow you can select an action associated to it such as traffic-rate, redirect or drop. This will be implemented at the boarder router.

This has the following advantages:

1. Fine-Grained Control: Flowspec allows for detailed and specific traffi management rules.
2. Centralized Management: Leveraging the BGP control plane, it enables easy and simultaneous updates to all routers in a network.
3. Effective Mitigation: It is particularly effective in mitigating DDoS attacks within a single network or AS.

Though comes with some downsides:

1. Inter-Domain Deployment: Flowspec’s effectiveness diminishes when rules need to be applied across multiple AS, especially if these AS belong to competing networks. Trust and cooperation are crucial but often lacking.
2. Scalability Issues: For large-scale attacks originating from many sources, creating numerous rules or aggregating sources into a single prefix can be challenging and inefficient.

Practically due to the need for trust this is only deployed within a AS and is not used more broadly.