Guidelines for assignment of IP address space
Contents
[hide]Guidelines for Assignment of IP Address Space
Premise:
IP address space is a limited resource on which the operation of the Internet depends. In the face of a rapidly expanding Internet, available IP address space is similarly being consumed. As such, ARIN, the organization responsible for assignment of IP address space for the Americas, has established practices and policies that are used to guide the assignment of IP address space. Gaslight Media is compelled by agreement to cooperate with the effort to conserve address space and abide by ARIN’s policies, and has therefore established these guidelines for assignment of IP address space to our customers.
Standards:
ARIN uses various standards documents as their guide for assignment of IP address space. Briefly, those documents outline appropriate practices and policies for conservation of IP address space and are based on the following principals.
- Globally routable IP address space should only be used for networks that are connected to the Internet, not for isolated internal networks.
- Address space should be subdivided (segmented into subnets) in such a way as to maximize the efficient use of address space.
- Network Address Translation (NAT) should be used, wherever possible, to avoid having to assign an IP addresses to each individual device that may appear on the network.
- Address space should only be assigned based on short and mid term needs.
- Requests for IP address space should include enough detail to properly evaluate the need for that address space.
- Actual use of IP address space should be periodically verified and unused space should be returned to the pool of available addresses.
Discussion:
Gaslight Media assigns IP address space to customers based on their need for that address space. Customers who need assigned address space will generally fall into one of the following categories.
- Dial-in customers who require the same IP address each time they connect. This relatively unusual case could be required for certain specific applications, such as some types virtual private networks.
- Dedicated connectivity customers who have server systems inside their network that need to be globally routable.
- Dedicated connectivity customers who have a specific need for user machines inside their network to be globally routable.
- Larger dedicated connectivity customers who require a number of globally routable addresses to support a large number of systems via Network Address Translation.
- Downstream ISP’s and other organizations that require larger contiguous blocks of IP address space.
Gaslight Media is experienced in technical practices, such as NAT, that can be used to conserve address space. We ask that our customers cooperate with us in deploying these technologies. Not only will this help to conserve IP address space, but will also benefit the customer in the long run in the following ways.
- IP address space assigned to customers is not transferable when those customers later switch to another provider. If a customer uses Network Address Translation (NAT) with address space set aside for internal private networks, no configuration changes will be required for systems in that network when changing providers.
- ARIN is now charging a fee for assignment of IP address space and it’s therefore becoming common for ISP’s to in turn charge their customers for assignment of IP address space to them. By using NAT and internal private network address space, customers can avoid current IP address charges and unknown future fee increases.
- Large blocks of address space have been set aside for internal private network address space. Using that IP address space allows a customer to assign large subnets where the potential for future expansion is unknown and thus avoid the need to reconfigure subnets and all machines associated with them in the future.
Certain large customers may be able to apply directly to ARIN for IP address space and, where this is appropriate, Gaslight Media can assist in that application. In reality, few customers will qualify for this type of assignment unless they meet the following requirements.
- The customer must be multi-homed (connected to more than one up-stream Internet provider).
- The customer must qualify for a block large enough to be globally routable.
Customer’s who wish to apply directly to ARIN for address space should be aware that there is no guarantee that such address space will route globally through the Internet. Also, small blocks of address space, such as individual class C’s, may not be routed by all providers and larger blocks may be required to route globally in the future.
Gaslight Media Assignment Policies:
The following policies establish a process by which Gaslight Media can efficiently assign address space to customers. We appreciate your cooperation with these policies, as do all users of the Internet who share our limited IP address space resources. In all cases, Gaslight Media will assist customers in the preparation of any documentation required in the policies below.
- Initial address space assignment
- All dedicated access customers will be assigned one IP address for the public side interface of their on-site router.
- Customers who show a need for globally routable IP address space for systems within their network will receive an initial assignment of a /29 (6 useable IP addresses). To receive this assignment, they must …
- Have a legitimate need for globally routable address space.
- Provide a short description of why systems within their network need to be globally routable.
- Customers who request initial address space larger than a /29 must …
- Have a legitimate need for globally routable address space.
- Submit a network address utilization summary with immediate, 6 month and one year projections showing…
- 25% immediate utilization
- 50% utilization within one year
- Submit a short description of why internal private address space cannot be used for these additional systems.
- Additional address space assignments
- Customers who request additional must …
- Have utilized at least 50% of existing assignments.
- Submit a network address utilization summary with immediate, 6 month and one year projections.
- Submit a short description of why internal private address space cannot be used for these additional systems.
- The size of additional assignments will be selected based on the following criteria …
- 25% immediate utilization
- 50% utilization within one year
- Customers who request additional must …
- Review of existing address assignments
- Gaslight Media reserves the right to verify utilization of existing address assignments at such times as that may be appropriate
- Assignments that are not 50% utilized after one year may be adjusted and some portion of that address space may be withdrawn.
- Cost of IP address space
- Single IP address assignments for the public port of a dedicated access customer’s router will be provided at no cost to the customer.
- Customers will be charged a recurring fee for the use of IP address space larger than a single address according to the following schedule.
- (list fee schedule here)
- Customers required to submit a network address utilization summary should use the form shown in the following example.
Network utilization for: Smith Consulting Date submitted: 11/14/2001 Network Overview: Smith Consulting consists of one central office and one remote office. In the central office we run our own mail server, a firewall and a couple user systems that frequently establish VPN connections to a custom information database to which we subscribe. The rest of our 30 or so computers will be running behind our firewall using NAT. The remote office does not have a firewall, but does have one user who also needs VPN access to the custom database. Starting IP Subnet Size Immediate 6 Months 1 year Remarks 208.163.184.0 14 5 7 8 Front office 208.163.184.32 6 2 3 3 Remote Office
Summary
IP address conservation is critical to the livelihood of the Internet. Current and future development, such as Ipv6, will go a long way toward relieving us of this burden, but full implementation is still at least several years off. If you have any questions about this policy or any aspect of IP addressing, please contact our technical services office or your Gaslight Media sales contact.
Reference Material
IP ADDRESSING and SUBNETTING INFORMATION
========================================
Network Type Addresses Subnet Mask Classical
/32 1 255.255.255.255 Individual Address
/31 2 255.255.255.254 (useless netmask)
/30 4 255.255.255.252
/29 8 255.255.255.248
/28 16 255.255.255.240
/27 32 255.255.255.224
/26 64 255.255.255.192
/25 128 255.255.255.128
/24 256 255.255.255.0 Class C
/23 512 255.255.254.0
/22 1,024 255.255.252.0
/21 2,048 255.255.248.0
/20 4,096 255.255.240.0
/19 8,192 255.255.224.0
/18 16,384 255.255.192.0
/17 32,768 255.255.128.0
/16 65,536 255.255.0.0 Class B
/15 131,072 255.254.0.0
/14 262,144 255.252.0.0
/13 524,288 255.248.0.0
/12 1,048,576 255.240.0.0
/11 2,097,152 255.224.0.0
/10 4,194,304 255.192.0.0
/9 8,388,608 255.128.0.0
/8 16,777,216 255.0.0.0 Class A
/7 33,554,432 254.0.0.0
/6 67,108,864 252.0.0.0
/5 134,217,728 248.0.0.0
/4 268,435,456 240.0.0.0
/3 536,870,912 224.0.0.0
/2 1,073,741,824 192.0.0.0
/1 2,147,483,648 128.0.0.0
/0 4,294,967,296 0.0.0.0 All address space
Non-Registered IP Address Space
-------------------------------
See RFC 1597 - Address Allocation for Private Internets
RFC 1631 - The IP Network Address Translator (NAT)
IP address space for private networks:
/8 10.0.0.0 - 10.255.255.255
/12 172.16.0.0 - 172.31.255.255
/16 192.168.0.0 - 192.168.255.255
===================
SUBNET TABLE
===================
Subnet Mask #Subnets/#Hosts Network# IP-Range Broadcast
==============================================================
.0/24 0/254 .0 .1-.254 .255
--------------------------------------------------------------
Subnet Mask #Subnets/#Hosts Network# IP-Range Broadcast
==============================================================
.128/25 2/126 .0 .1-.126 .127
.128 .129-.254 .255
--------------------------------------------------------------
Subnet Mask #Subnets/#Hosts Network# IP-Range Broadcast
==============================================================
.192/26 4/62 .0 .1-.62 .63
.64 .65-.126 .127
.128 .129-.190 .191
.192 .193-.254 .255
--------------------------------------------------------------
Subnet Mask #Subnets/#Hosts Network# IP-Range Broadcast
==============================================================
.224/27 8/30 .0 .1-.30 .31
.32 .33-.62 .63
.64 .65-.94 .95
.96 .97-.126 .127
.128 .129-.158 .159
.160 .161-.190 .191
.192 .193-.222 .223
.224 .225-.254 .255
--------------------------------------------------------------
Subnet Mask #Subnets/#Hosts Network# IP-Range Broadcast
==============================================================
.240/28 16/14 .0 .1-.14 .15
.16 .17-.30 .31
.32 .33-.46 .47
.48 .49-.62 .63
.64 .65-.78 .79
.80 .81-.94 .95
.96 .97-.110 .111
.112 .113-.126 .127
.128 .129-.142 .143
.144 .145-.158 .159
.160 .161-.174 .175
.176 .177-.190 .191
.192 .193-.206 .207
.208 .209-.222 .223
.224 .225-.238 .239
.240 .241-.254 .255
--------------------------------------------------------------
Subnet Mask #Subnets/#Hosts Network# IP-Range Broadcast
==============================================================
.248/29 32/6 .0 .1-.6 .7
.8 .9-.14 .15
.16 .17-.22 .23
.24 .25-.30 .31
.32 .33-.38 .39
.40 .41-.46 .47
.48 .49-.54 .55
.56 .57-.62 .63
.64 .65-.70 .71
.72 .73-.78 .79
.80 .81-.86 .87
.88 .89-.94 .95
.96 .97-.102 .103
.104 .105-.110 .111
.112 .113-.118 .119
.120 .121-.126 .127
.128 .129-.134 .135
.136 .137-.142 .143
.144 .145-.150 .151
.152 .153-.158 .159
.160 .161-.166 .167
.168 .169-.174 .175
.176 .177-.182 .183
.184 .185-.190 .191
.192 .193-.198 .199
.200 .201-.206 .207
.208 .209-.214 .215
.216 .217-.222 .223
.224 .225-.230 .231
.232 .233-.238 .239
.240 .241-.246 .247
.248 .249-.254 .255
--------------------------------------------------------------
Subnet Mask #Subnets/#Hosts Network# IP-Range Broadcast
==============================================================
.252/30 64/2 .0 .1-.2 .3
.4 .5-.6 .7
.8 .9-.10 .11
.12 .13-.14 .15
.16 .17-.18 .19
.20 .21-.22 .23
.24 .25-.26 .27
.28 .29-.30 .31
.32 .33-.34 .35
.36 .37-.38 .39
.40 .41-.42 .43
.44 .45-.46 .47
.48 .49-.50 .51
.52 .53-.54 .55
.56 .57-.58 .59
.60 .61-.62 .63
.64 .65-.66 .67
.68 .69-.70 .71
.72 .73-.74 .75
.76 .77-.78 .79
.80 .81-.82 .83
.84 .85-.86 .87
.88 .89-.90 .91
.92 .93-.94 .95
.96 .97-.98 .99
.100 .101-.102 .103
.104 .105-.106 .107
.108 .109-.110 .111
.112 .113-.114 .115
.116 .117-.118 .119
.120 .121-.122 .123
.124 .125-.126 .127
.128 .129-.130 .131
.132 .133-.134 .135
.136 .137-.138 .139
.140 .141-.142 .143
.144 .145-.146 .147
.148 .149-.150 .151
.152 .153-.154 .155
.156 .157-.158 .159
.160 .161-.162 .163
.164 .165-.166 .167
.168 .169-.170 .171
.172 .173-.174 .175
.176 .177-.178 .179
.180 .181-.182 .183
.184 .185-.186 .187
.188 .189-.190 .191
.192 .193-.194 .195
.196 .197-.198 .199
.200 .201-.202 .203
.204 .205-.206 .207
.208 .209-.210 .211
.212 .213-.214 .215
.216 .217-.218 .219
.220 .221-.222 .223
.224 .225-.226 .227
.228 .229-.230 .231
.232 .233-.234 .235
.236 .237-.238 .239
.240 .241-.242 .243
.244 .245-.246 .247
.248 .249-.250 .251
--------------------------------------------------------------
Subnet Mask #Subnets/#Hosts Network# IP-Range Broadcast
==============================================================
