Hi,
Regarding controlling how far a more specific travels, I've attached 'no-export' to more specific routes for TE purposes when advertising them to an upstream provider to limit their reach. Of course the trouble is that 'no-export' has a very limited scope. This discussion reminded me of this draft, which encodes an AS level hop count that can be used to limit route propagation, perhaps it or something similar needs to be revived: "The AS_HOPCOUNT Path Attribute 2. Introduction A prefix that is injected into BGP [RFC1771] will propagate throughout the mesh of all BGP speakers unless it is explicitly blocked by policy configuration. This behavior is necessary for the correct operation of BGP, but has some unfortunate interactions with current operational procedures. Currently, it is beneficial in some cases to inject longer prefixes into BGP to control the flow of traffic headed towards a particular destination. These longer prefixes may be advertised in addition to an aggregate, even when the aggregate advertisement is sufficient for basic reachability. This particular application is known as "inter-domain traffic engineering" and is a well-known phenomenon that is contributing to growth in the size of the global routing table [RFC3221]. The mechanism proposed here allows the propagation of those longer prefixes to be limited, allowing some traffic engineering problems to be solved without such global implications." https://tools.ietf.org/html/draft-ietf-idr-as-hopcount-00 Not covered in that draft, one thought would be that upstream operators could police something like this by only accepting more specifics of your aggregate with an AS_HOPCOUNT value of <= 10. Regards, Mark. _______________________________________________ GROW mailing list [email protected] https://www.ietf.org/mailman/listinfo/grow
