RFC 1787 (rfc1787) - Page 2 of 8
Routing in a Multi-provider Internet
Alternative Format: Original Text Document
RFC 1787 Routing in a multi-provider Internet April 1995
of Network Service Subscribers. Other providers place no constraints
on the subscribers that can subscribe to them, as long as the
subscribers pay the fee charged by the providers. Some of the
providers place certain constraints on the reselling of the
connectivity services by organizations (e.g., other providers)
attached to the providers. Some of the providers may be operated by
companies that are subject to specific regulations (e.g., regulated
monopoly), while other providers are completely unregulated. The
scope of geographical coverage among providers varies from a small
region (e.g., county, town) to a country-wide, international, or even
intercontinental.
There is no centralized control over all the providers in the
Internet. The providers do not always coordinate their efforts with
each other, and quite often are in competition with each other.
Despite all the diversity among the providers, the Internet-wide IP
connectivity is realized via Internet-wide distributed routing, which
involves multiple providers, and thus implies certain degree of
cooperation and coordination. Therefore, there is a need to balance
the providers' goals and objectives against the public interest of
Internet-wide connectivity and subscribers' choices. Further work is
needed to understand how to reach the balance.
2. Routing Requirements
Conceptually routing requirements can be classified into the
following three categories: source preferences, destination
preferences, and constraints on transit traffic. Source preferences
allow an originator of a packet to exert control over the path to a
destination. Destination preferences allow a destination to exert
control over the path from a source to the destination. Constraints
on transit traffic allow a provider to control the traffic that can
traverse through the resources (routers, links) controlled by the
provider.
From a conceptual point of view the requirements over the degree of
control for source and destination preferences may vary from being
able to just provide connectivity (regardless of the path), to being
able to select immediate providers, to more complex scenarios, where
at the other extreme a subscriber may want to have complete control
over the path selection.
From a conceptual point of view the requirements over the degree of
control for transit traffic may vary from control based only on the
direct physical connectivity (controlling the set of organizations
directly connected to the provider), to being able to restrict
traffic to a particular set of sources or destinations, or a
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