ipv6 subnet reserves 2 addresses in allocation pool
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
neutron |
Expired
|
Low
|
Unassigned |
Bug Description
consider this table:
125::/125 | {"start": "125::1", "end": "125::6"} |
126::/126 | {"start": "126::1", "end": "126::2"} |
127::/127 | |
128::/128 | |
all those subnets created with
neutron subnet-create --ip_version 6 --disable-dhcp --no-gateway NETWORK CIDR
You see that ::0 and the largest address in CIDR are reserved.
This is similar to ipv4 where we have network address and broadcast address, while
according to http://
Situation for prefixes 127 and 128 even worse, no addresses at all.
Changed in neutron: | |
importance: | Undecided → Low |
Changed in neutron: | |
status: | New → Confirmed |
Changed in neutron: | |
assignee: | nobody → Jacek Świderski (jacek-swiderski) |
Changed in neutron: | |
status: | Confirmed → In Progress |
Changed in neutron: | |
status: | In Progress → Confirmed |
I suggest such solution:
1) According to IETF all "not /64" subnets in IPv6 are risky, so no strict reservations should be done for them. Also no need to reserve broadcast address for them as it doesn't exist in IPv6. Subnet-router anycast address makes sense in all networks except of /127, /128:
A) If network mask is between 64 and 127, reserve only subnet-router anycast address, all others should be allocated for hosts.
B) If network mask is 127 or 128, don't reserver anything.
2) In all /64 and bigger networks all reservations according to "Interface IID" document should be done: http:// www.iana. org/assignments /ipv6-interface -ids/ipv6- interface- ids.xhtml