On 18/Jun/20 12:28, Robert Raszuk wrote:
To your IGP point let me observe that OSPF runs over IP and ISIS does not. That is first fundamental difference. There are customers using both all over the world and therefore any suggestion to just use OSPFv3 is IMHO quite unrealistic.
Are you saying that OSPF houses that want IPv6 should just move to IS-IS. Don't get me wrong, I support that very much as I think IS-IS is a great IGP. That said, while it's good to convince OSPF operators to consider IS-IS, it's not our place to force them to use it. Also, OSPFv3-only for your dual-stack IGP needs is a supported capability. Last time I tested it in Juniper in 2010/2011, it worked well. I don't know if anyone is actually running IPv4 and IPv6 on OSPFv3 only, but it does work.
Keep in mind that OSPF hierarchy is 2 (or 3 with super area) while in IETF there is ongoing work to extend ISIS to 8 levels. There is a lot of fundamental differences between those two (or three) IGPs and I am sure many folks on the lists know them.
15+ years ago, I'd have said that one protocol may have been suited to a specific task than another due to the control plane limitations of the day. In 2020, with the state-of-the-art of control planes today, it near as makes no difference, IMHO.
Last there is a lot of enterprise networks happily using IPv4 RFC1918 all over their global WAN and DCs infrastructure and have no reason to deploy IPv6 there any time soon.
No wonder the vendors aren't seeing any LDPv6, SR-ISISv6 or SR-OSPFv3 demand :-). Mark.