My company is building a national backbone network, leveraging leased lines and dark fiber from Tier 1/2/3 providers. What we've found is that when we buy IP in the major markets, our traffic does not flow deterministically with AS-Path as the metric. This is because most of the major providers give their customers one local preference value, and their peers another, in an effort to ensure SLAs are met by keeping customer traffic on-net for as long as possible. There are varying values assigned, and some vendors don't offer community values to neutralize this effect.
I'm wondering if anyone has dealt with this in the past, or if it would be possible to have some sort of agreement on local preference manipulation. Something similar to the below:
1. All vendors must offer at least 5 community values for local preference. This is to allow for customer-based multivendor traffic engineering.
2. All vendors must offer a local preference community value greater than their best default metric.
3. All vendors must offer a local preference community value lesser than their worst default metric.
4. All vendors should offer a range of community values both above and below local preference 100.
5. All vendors should make an effort to standardize the values/value ranges offered with other vendors.
6. All vendors should offer a local preference matrix to their customers, listing the changes made to a specific AS (e.g. another vendor) to aid the customer in making an intelligent routing decision for load balancing and traffic engineering in a multivendor BGP environment.
It's obviously something that each of us would need to do individually, but I'm wondering if there is any way this could become a de facto standard, or could be a method that the community at large could enforce somehow.
Brian A . Rettke
RHCT, CCDP, CCNP, CCIP
Network Engineer, CableONE Internet Services