I got a /80 prefix from the upstream router. As it's smaller than /64, SLAAC is not available to assign addresses. And according to the wiki,

RouterOS DHCPv6 server can only delegate IPv6 prefixes, not addresses.

. Is there any other way to delegate addresses, or any plan for adding support of address delegating with DHCPv6 server?

I got a /80 prefix from the upstream router. As it's smaller than /64, SLAAC is not available to assign addresses.

That is broken, for example Android does not support DHCPv6 only SLAAC so you would not be able to use any Android device.

Get whoever manages the upstream router to provide as sensibly sized prefix, suggest they read https://www.ripe.net/publications/docs/ripe-690

I got a /80 prefix from the upstream router.

Ahh, someone upstream is still thinking of ipv6 like it is ipv4 and they want to conserve addresses.

I know this is not a problem you can fix, but you and others might find the following interesting.

This is a good read about how people have to get their head out of the ipv4 concepts of preserving addresses space with ipv6 https://www.networkworld.com/article/22 ... ement.html
"The IANA and all the RIRs recommend using /64 subnets everywhere in your network, including on point-to-point links. But so many designers just can't bring themselves to do it."

And to get your head around the sheer size of the ipv6 address space, take a look at the subnets.
https://www.crucial.com.au/blog/2011/04 ... reference/

Global unicast an /64 for point to point transfer networks between routers is not desirable, becasue neighbor exhaustion attacts might bring your network down.

Either use fe80::/64 (Administratively set fe80::/64 and fe80::1/64 for each routers interface)
Or use global unicast with a /127 subnetmask but still reserve a /64 for readability reasons.

Anyways: Subnet-masks between /64 and /127 are prohibitve, of course!

@hzdrro: You can use external DHCPv6 server, it doesn't have to be the router itself. Major downside is that you need another device to run it.