IPv4, with its 32-bit address format, supports around 4.3 billion addresses. Initially sufficient, the explosion of internet-connected devices has rapidly exhausted these addresses. Internet Service Providers (ISPs) are the biggest owners of public IPv4 addresses blocks as they provide enterprise and home access to the Internet, along with services such as IPTV and IP telephony. Three major issues associated with IPv4 are IP address depletion, increased network complexity due to Internet routing table growth, and lack of end-to-end connectivity because of Network Address Translation (NAT) used at Customer Premise Equipment (CPE) or Internet Access Device (IAD).

Nowadays, small and medium-sized ISPs face three main pain points with IPv4 addressing: the limited number of available addresses, the difficulty in managing and allocating addresses, and the high cost of purchasing additional IPv4 address space, which increase over time. Consequently, IPv4 block conservation becomes crucial. This blog post provides comprehensive insights into how 6WIND could ease ISPs IPv4 address management and optimization introducing its virtual Broadband Network Gateway (vBNG) and virtual Carrier Grade NAT (vCGNAT) products in their backhaul network.

ISP IPv4 Address Life Cycle Management without BNGs
The current ISP backhaul network relies on CMTS, DSLAM and OLT type of access devices to manage subscriber connectivity. These devices can provide a layer 2 connection from the CPE or IAD to a router that acts as their IP anchor point. Sometime these access devices can also serve directly as the layer 3 anchor point for subscribers, acting as their IP default gateway. From an IP management perspective, ISPs need to provision an IP block in advance on each of these access devices, which could number in the hundreds or thousands within a network. Dividing an IP macro block into multiple IP micro blocks and allocating these micro blocks to the access devices in advance is inefficient because many public IPv4 addresses are lost in that split and allocation. The ISPs are provisioning in advance the micro blocks because they don’t know which access device will acquire a new subscriber. This phenomenon results in a “waste” of public IPv4 addresses, often leading to a ratio of 4 public addresses being used per subscriber, which is far from optimal for ISPs with limited critical resources. This inefficient provisioning often prevents ISPs from acquiring new customers due to the lack of available IPv4 addresses, potentially forcing a hasty transition to IPv6.

Benefits of 6WIND virtual BNG
Using 6WIND virtual BNG helps ISPs achieve a Public IPv4 address per subscriber ratio close to 1:1. By positioning the virtual BNG at a “upper” level, ISPs can acquire subscribers across any access devices saving precious Public IPv4 addresses.