ip addressing policy
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Introduction and Overview
In the United States we are governed by the American Registry for Internet Numbers (ARIN). ARIN provides the IP space that we distribute to our customers. Most companies need to contact their Internet provider, in this case tw telecom, to obtain IP Address space. In order for tw telecom to acquire address space from ARIN, we must follow their policies for allocations and assignments to our customers and enforce efficient utilization of IP addresses. This means that our customers must justify their IP needs to us in detail in accordance with ARIN's guidelines for efficient usage.
All information disclosed to tw telecom during this process is confidential, with a single exception. We are required to provide ARIN with the same IP assignment information you provide to us if they request it. This information is often requested when tw telecom seeks to obtain more address space for assignment to customers.
ARIN's policies can be found on their website. Links to the ARIN website are at the bottom of the page.
As per ARIN policies, all IP assignments must be accounted for, and each address block must be documented via SWIP, RWHOIS or internal databases. tw telecom uses an RWHOIS server for all assignments, except where SWIP assignment is necessary. Large address consumers will also be required to maintain, and provide upon request, a database of how addresses are assigned internally.
The minimum direct allocation ARIN can provide is a /20 for single homed network service providers, a /22 for multi-homed network service providers, and a /24 assignment for multi-homed end user organizations.
Guidelines and Rules
- tw telecom assigns IPv6 net blocks upon request. A single direct network will be assigned a /64, a network with a routed connection will receive a /56. Any request for a /48 must explain why more than 256 /64 blocks is necessary. Please note Provider Independent (PI) space is required to multi-home with IPv6 and these /48 net blocks must be requested directly from ARIN.
- tw telecom typically will not provide aggregate IPv4 allocations larger than a /24.
- tw telecom typically will not provide allocations or assignments to customers who already have a direct allocation from ARIN.
- tw telecom will not provide additional allocations or assignments until all previous net blocks have reached an 80% utilization rate.
- A usage figure of 80% must be achieved within 90 days after allocation/assignment, or the addresses will be withdrawn. (80% usage is based on SWIP records and a scan run against all assigned net blocks.)
- Customers must maintain proper reverse DNS records for all assigned or allocated addresses.
- Customers will not be given address space for administrative convenience.
- tw telecom cannot guarantee the assignment of contiguous net blocks.
- tw telecom reserves the right to change customer assignments/allocations as necessary.