On 12.02 21:31, Gert Doering wrote:
... We want to include AS numbers in the addressing scheme for point to point links (= 16 bits lost), and sequence numbers (another 16 bits, for ease of addressing). So if you do /64s on ptp links, plus 2 times 16 bits for enumeration, you need a /32 to handle all your point to point links. Add a router number (16 bits), you'd even need a /16 for this. ...
I'll admit that I do not follow the details of this discussion but I want to offer a bit of general advice based on considerable operational experience: Overloading layer three addresses with clever numbering schemes never works in the long run. Why? As netowrks grow the room for "structure" in adresses will constrict. Lower layer technology will change underneath the numbering scheme. Higher layer technology will change above the numbering scheme. Network design will change .... somewhere, somehow. ;-) If you are not convinced yet, look at the "evoloution" of any arbitrary telephone numbering plan. What "structure" should L3 addresses have then? L3 addresses should closely reflect L3 routing domains. That's all! Not more, not less. To amplify: L3 addresses should be designed to closely reflect present and *future* L3 routing domains. The art in making addressing plans is to use the "structure" part such that routing structure can easily be added later. This involves leaving a number of bits unused in strategic places. It certainly does not mean to cram as much information in the address as possible to make it "easier to read". Addresses should be read through a network design database. I think vendors will learn that qickly with those long addresses. Is the IETF doing any standardisation work in this area? Maybe it should. Daniel