On Wed, 18 Feb 2015, Methsri Wickramarathna wrote:
My company has 3 upstream providers and we are serving more than 400 customers ..In that case we have to manage our upstream capacity... When considering capacity managing normally we just transfer a /24 from congested Up stream provider to non congested provider. Issue we have is we don't know exactly the usage of a /24 subnet before transfer.
Netflow/sflow/IPFIX is most likely going to be the easiest/cleanest way to get the data you want. I would also recommend announcing a consistent set of prefixes to all 3 providers, and using mechanisms like AS-PATH prepending and/or whatever BGP communities each provider offers to do things like tweak preferences or do selective prepending, rather than shuffling prefixes between providers to achieve some level of traffic engineering, and also keeping your announcements aggregated as much as possible. Less routing table bloat and churn is a good thing. jms