[arin-ppml] Draft Policy ARIN-2013-2: 3GPP Network IP Resource Policy

ARIN info at arin.net
Wed Mar 27 14:20:27 EDT 2013

Draft Policy ARIN-2013-2
3GPP Network IP Resource Policy

On 21 March 2013 the ARIN Advisory Council (AC) accepted "ARIN-prop-184 
3GPP Network IP Resource Policy" as a Draft Policy.

Draft Policy ARIN-2013-2 is below and can be found at:

You are encouraged to discuss the merits and your concerns of Draft 
Policy 2013-2 on the Public Policy Mailing List. 2013-2 will also be on 
the agenda at the upcoming ARIN Public Policy Meeting in Barbados. The 
AC will evaluate the discussion in order to assess the conformance of 
this draft policy with ARIN's Principles of Internet Number Resource 
Policy as stated in the PDP. Specifically, these principles are:

  * Enabling Fair and Impartial Number Resource Administration
  * Technically Sound
  * Supported by the Community

The ARIN Policy Development Process (PDP) can be found at:

Draft Policies and Proposals under discussion can be found at:


Communications and Member Services
American Registry for Internet Numbers (ARIN)

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Draft Policy ARIN-2013-2
3GPP Network IP Resource Policy

Date: 27 March 2013

Problem Statement:

Current 3GPP architectures consist of hierarchical aggregation, from 
cell site up to anchor nodes, approximately one per NFL city. Anchor 
nodes are the point where IP addresses are assigned and topologically 
positioned in the network. Generally an anchor node must be provisioned 
with enough addresses to handle all simultaneously attached users, plus 
enough headroom to handle failover from an adjacent anchor node in the 
event of an outage. Capacity planning generally ensures that all anchor 
nodes have approximately the same number of attached users at steady 
state. Moving addresses between anchor nodes would require significant 
renumbering effort and substantial increases in operational complexity, 
so cannot be performed during an outage. Generally addresses are not 
renumbered between anchor nodes: instead, aggregation nodes can be 
rehomed as needed to balance steady state capacity levels. Because of 
the 3GPP architecture's failover and capacity planning requirements, all 
cellular networks target approximately 50% simultaneous usage of each 
anchor node's IP addresses. However, even at 50% usage, the total number 
of subscribers generally exceeds the number of addresses needed.

Currently, a number of mobile networks are using non-RIR-assigned space 
internally to meet customer demand. However, there is insufficient 
private space (RFC1918, etc.) available for internal use, so other 
unassigned space is currently being used. As this unassigned space is 
brought into service via reclamation, returns, and transfers, it is no 
longer possible to use it internally, so globally unique space must be 
used instead. As a result, most of the need for additional RIR-assigned 
space is to serve existing customers, not to accommodate future growth.

Policy statement:

I can see two possible approaches to address this need. One approach 
would be to continue counting simultaneously attached users to measure 
IP needs, and apply a 50% usage requirement to justify allocations. 
Another approach would be to instead count total subscribers (rather 
than simultaneously attached users), and apply a much higher threshold, 
such as 80% or even 90%, to justify allocations.

Timetable for implementation: ASAP

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