- The BGP Metric is not simple.
- Attributes are ways that you can ‘tag’ incoming or outgoing BGP routes
- Some attributes are well known (everyone supports) while others are optional.
- Some attributes are mandatory (must be in a BGP update) while others are discretionary.
- Some attributes are transitive (travel from router to router) while others are non-transitive.
xxxx: Official Standards based categories of attributes.
Well Known Attributes:
- Autonomous System Path (AS-PATH – Mandatory)
- Next Hop Address (Mandatory)
- Local Preference (Discretionary)
- Atomic Aggregate (Discretionary)
- Multi-exit discriminator (MED/Metric)