Internet
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... address allocation and management are essential
operational functions for the Public Internet. The exact policies for
IP unicast address ...
... unicast address allocation and management policies for the Public
Internet, and to provide recommendations with respect to these
policies.
...
... address ownership" and "address lending," and the technical
implications of these policies for the Public Internet. For the
organizations that could provide reachability to a sufficiently large
...
... reachability to a sufficiently large
fraction of the total destinations in the Internet, and could express
such reachability through a single IP address prefix ...
... "address ownership" policy to every individual site or organization
that connects to the Internet results in a non-scalable routing.
...
... lending" policy should be formally added to the set of address
allocation policies in the Public Internet. The document also
recommends that organizations that do not provide a sufficient degree
of routing information ...
... routing information aggregation, but wish to obtain access to the
Internet routing services should be strongly encouraged to use this
...
... IP unicast address is its ability to
interact with the Public Internet routing service and thereby
...
... routing service and thereby
exchange data with the remainder of the Internet. In other words, for
the Public Internet, it is the reachability ...
... exchange data with the remainder of the Internet. In other words, for
the Public Internet, it is the reachability of an IP address that
...
... gives it an intrinsic value. Observe, however, that IP addresses are
used outside of the Public Internet. This document does not cover the
value of addresses in other than the Public Internet ...
... Public Internet. This document does not cover the
value of addresses in other than the Public Internet context.
...
... Public Internet it is the service
environment (the Internet) and its continued operation, including its
routing system, which gives an IP address ...
... routing system, which gives an IP address its intrinsic value, rather
than the inverse. Consequently, if the Public Internet routing system
ceases to be operational, the service ...
... service disappears, and the addresses
cease to have any functional value in the Internet. At this point,
for the Public Internet, all address ...
... cease to have any functional value in the Internet. At this point,
for the Public Internet, all address allocation and management
...
... routing system. It is the only proven
mechanism for scaling routing to the current size of the Internet.
...
... Scaling the Internet routing system ...
...
The enormous growth of the Public Internet places a heavy load on the
Internet routing system ...
... The enormous growth of the Public Internet places a heavy load on the
Internet routing system. Before the introduction of CIDR the growth
...
... months. Even if we could double the capacities of the routers in the
Internet every 24 months, inevitably the size of the routing tables
is going to exceed the limit of the routers ...
... is going to exceed the limit of the routers. Therefore, to preserve
uninterrupted continuous growth of the Public Internet, deploying
mechanisms that contain the growth rate of the routing information is
...
...
Lacking mechanisms to contain the growth rate of the routing
information, the growth of the Internet would have to be either
limited or frozen, or the Internet routing system ...
... routing
information, the growth of the Internet would have to be either
limited or frozen, or the Internet routing system would become
overloaded ...
... RFC1518, RFC1519] has been
deployed since late 1992 in the Public Internet as the primary
mechanism to contain the growth rate of the routing information -
...
... routing information -
without CIDR the Internet routing system would have already
collapsed. For example, in October 1995, within AlterNet (one of the
...
... routing system would have already
collapsed. For example, in October 1995, within AlterNet (one of the
major Internet Service Providers) there were 3194 routes. Thanks to
aggregation, AlterNet advertised only 799 routes to the rest of the
...
... aggregation, AlterNet advertised only 799 routes to the rest of the
Internet - a saving of 2395 routes (75%) [Partan 95]. In October 1995
the Internet Routing Registry ...
... Internet - a saving of 2395 routes (75%) [Partan 95]. In October 1995
the Internet Routing Registry (IRR) contained 61,430 unique prefixes
listed, not counting prefixes ...
... resulted in less than 30,000 routes in the default-free part of the
Internet routing system [Villamizar 95].
...
... CIDR is an example of the application of hierarchical routing in the
Public Internet, where subnets, subscribers, and finally providers
...
... Because of pre-CIDR address allocation, many routes in the Internet
are not suitable for hierarchical aggregation. Moreover, unconnected
...
... CIDR address allocations exist. If these sites connect
to the Internet at some point in the future, the routes to these
sites are unlikely to be suitable for hierarchical aggregation. Also,
...
... management policies yield scalable routing. The Internet routing
system is subject to both technological and fundamental constraints ...
... The "address ownership" allocation policy and its implications on
the Public Internet ...
... address ownership" policy, the organization would be able to use
these addresses to gain access to the Internet routing services,
...
...
While it has never been explicitly stated that various Internet
Registries use the "address ownership" allocation policy, it has
always been assumed (and practiced).
...
... ("portable" addresses) on the scalability of the Internet routing
system, one must observe that:
...
... Specifically, the assignee is not required (but may be influenced)
to relinquish the ownership as the connectivity of the assignee to
the Internet changes.
(b) By definition, hierarchical routing ...
... topology (or at least certain pieces of it) will
be permanently fixed. Given the distributed, decentralized, largely
unregulated, and global (international) nature of the Internet,
constraining the Internet topology ...
... unregulated, and global (international) nature of the Internet,
constraining the Internet topology (or even certain parts of it) may
have broad technical, social, economical, and political implications.
...
... To date, little is known of what these implications are; even less is
known whether these implications would be acceptable (feasible) in
practice. Therefore, at least for now, we have to support an Internet
with an unconstrained topology (and unconstrained topological
...
... topology changes), we can either have address ownership for everyone
or a routable Internet, but not both, or we need to develop and
deploy new mechanisms (e.g., by decoupling the address owned by the
...
... deploy new mechanisms (e.g., by decoupling the address owned by the
end users from those used by the Internet routing, and provide
mechanisms to translate between the two). In the absence of new
...
... overhead will lead to a breakdown of the
routing system resulting in a fragmented (partitioned) Internet.
Alternately, we can have a routable Internet, but without address ...
... routing system resulting in a fragmented (partitioned) Internet.
Alternately, we can have a routable Internet, but without address
ownership ("portable" addresses ...
... The "address lending" allocation policy and its implications for the
Public Internet ...
... This document expects that the "address lending" policy would be used
primarily by Internet Registries associated with providers; however,
this document does not preclude the use of the "address lending"
...
... this document does not preclude the use of the "address lending"
policy by an Internet Registry that is not associated with a
provider.
...
... This document expects that when the "address lending" policy is used
by an Internet Registry associated with a provider, the provider is
...
... aggregation of these addresses to a degree
that is sufficient to achieve Internet-wide IP connectivity.
...
... This document expects that when the "address lending" policy is used
by an Internet Registry associated with a provider, the terms and
conditions of the loan would be coupled to the service ...
... address
prefix. This reduces the routing information that needs to be carried
by the Internet routing system (for more information, see Section
5.3.1 of RFC1518hist ...
... appropriately, could play an important role in enabling the
continuous uninterrupted growth of the Internet.
...
...
Organizations connecting to the Internet should be aware that even if
their current provider, and the provider ...
... switch to in the future
do not require renumbering, renumbering may still be needed to
achieve Internet-wide IP connectivity. For example, an organization
may now receive Internet service ...
... Internet-wide IP connectivity. For example, an organization
may now receive Internet service from some provider and allocate its
addresses ...
... prefix (that covers
destinations within the organization) to the rest of the Internet.
However, if one or more other providers exist, that are unwilling or
unable to accept the longer prefix ...
... then the organization would not have IP connectivity to part of the
Internet. Among the possible solutions open to the organization may
be either to renumber, or for others to acquire connectivity to
providers that are willing and able to accept the prefix ...
...
Observe that the goal of hierarchical routing in the Internet is not
to reduce the total amount of routing information in the Internet ...
... Internet is not
to reduce the total amount of routing information in the Internet to
the theoretically possible minimum, but just to contain the volume of
routing information ...
... reachability to a sufficiently large fraction of the
total destinations in the Internet and could express such
reachability through a single IP address prefix ...
... prefix will be maintained throughout the default-free
part of the Internet routing system, regardless of where they connect
to the Internet ...
... Internet routing system, regardless of where they connect
to the Internet. Therefore, using the "address ownership" policy
when allocating addresses ...
... connectivity, the reachability information they inject into the
Internet routing system should be subject to hierarchical
...
... aggregation
difficult, if not impossible. This, in turn, has a very detrimental
effect on the Internet routing system. To prevent the collapse of the
Internet ...
... Internet routing system. To prevent the collapse of the
Internet routing system, for such organizations, this document
recommends using the "address ...
... recommends using the "address lending" policy. Consequently, when
such an organization first connects to the Public Internet or changes
its topological attachment to the Public Internet, the organization
...
... such an organization first connects to the Public Internet or changes
its topological attachment to the Public Internet, the organization
eventually needs to renumber. Renumbering allows the organization to
withdraw any exceptional prefixes ...
... withdraw any exceptional prefixes that the organization would
otherwise inject into the Internet routing system. This applies to
the case where the organization takes its addresses ...
... address ownership," nor the "address
lending" policy, by itself, is sufficient to guarantee Internet-wide
IP connectivity. Therefore, we recommend that sites with addresses ...
... routing information to its direct provider. Connectivity to the rest
of the Internet can be handled by mediating gateways (e.g.,
application layer ...
... that use of mediating gateways eliminates the need for renumbering,
and avoids burdening the Internet routing system with non-
aggregatable addressing ...
... management policy for IP addresses used
for Internet connectivity must take into account its impact on the
scalability of the Public Internet ...
... Internet connectivity must take into account its impact on the
scalability of the Public Internet routing system. Among all of the
possible address ...
... routing system are feasible. All other policies
are self-destructive in nature, as they lead to a collapse of the
Internet routing system, and therefore to the fragmentation
...
... address ownership
have an extremely negative impact on the scalability of the Internet
routing system. Such policies are almost certain to exhaust the
...
... routing system. Such policies are almost certain to exhaust the
scalability of the Internet routing system well before we approach
the exhaustion of the IPv4 address ...
... IPv4 address space and before we can make
effective use of the IPv6 address space. Given the Internet's growth
rate and current technology, the notion that everyone can own address
space and receive Internet-wide ...
... Internet's growth
rate and current technology, the notion that everyone can own address
space and receive Internet-wide routing services, despite where they
...
... routing services, despite where they
connect to the Internet, is currently technically infeasible.
Therefore, this document makes two recommendations. First, the
"address ...
... address lending" policy should be formally added to the set of
address allocation policies in the Public Internet. Second,
organizations that do not provide a sufficient degree of routing
information aggregation ...
... organizations that do not provide a sufficient degree of routing
information aggregation to obtain access to the Internet routing
services ...
... access control from external networks, such as The Internet, to their
internal systems. Such firewalls might include access control ...