Comcast’s Xfinity broadband network — 20.28 million subscribers — is on its way to becoming one of world’s largest IPv6 networks, thanks to a new software upgrade by ARRIS (s ARRS), a cable equipment maker. The Suwanee, Ga.-based company (that also includes Motorola’s Home Business) recently released a software upgrade that has enabled IPv6 support for more than 4 million ARRIS TG862 gateways —boxes that are used to connect to the Internet, offer phone service and act as a wireless access point—  currently deployed across the Comcast (s CMCSA) broadband network. Comcast has been planning to completely rollout IPv6 across its network by early 2014.