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North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical RE: IPV4 as a Commodity for Profit
> Operational comment: Look on the bright side, they may follow > Comcast's example and deploy ipv6 instead! Or they may not, and their share price will suffer as a result. People making the technical decision to stick with IPv4 for their large network are also making a decision to limit the growth of the network and to limit the growth of the business. As the IPv4 exhaustion issue becomes more widely understood, companies who have not prepared themselves to deploy IPv6 will find themselves under increasing scrutiny by shareholders. Comcast moved to IPv6 because their network was running out of RFC 1918 space. Since DOCSIS 3 includes IPv6 support, they made the decision to go to IPv6 rather than continue to spend money on shoehorning themselves into the limited IPv4 address space. Many people have not yet come to terms with how big the IPv6 space is, even the /32 that an ISP gets or the /48 that a site gets. We probably need to start talking about the number of subnetting bits available. For instance, an IPv4 ISP who assigns a /24 to subnets within their architecture and who has a /16 allocated for their architecture, has 8 bits available to subnet with. If an IPv6 ISP decides to assign a /64 to subnets and allocate a single /48 then they will also have 8 subnet bits available. So you could consider a /48 to be roughly equivalent to an IPv4 /16. Now, if an IPv6 ISP decides to strictly follow the rule of assigning a /48 per site internally, then each PoP or data center will be allocated a /48 meaning that each PoP or data center now has 8 subnet bits available. This amount of legroom allows you to do things like standardize subnet layouts for all sites, regardless of size, including the actual bits used from the 8 subnet bits. For instance, you can predict that if a PoP has 2001:1918:123/48 you know that if there is a switch connecting to a data center at that site, it will have the IPv6 address 2001:1918:123:d033::1 because your standard design has ::d033/64 assigned to the switch filling that role and Interface ID 1 assigned to its management interface. This kind of standardization makes it much easier to deploy PoPs regardless of whether it is in Dubai, where the data center is a half rack of webservers, or The Dalles where it is a 40,000 square foot warehouse. It also simplifies management and troubleshooting of the network. --Michael Dillon
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