About the IPv6 Address Usage Policy for STNET
For the Institute of Science Tokyo's campus network (STNET), the IPv6 address numbering plan was revised in FY2022. This page provides an overview of the IPv6 address allocation policy for users.
1. Address Blocks Held
The university holds the following IPv6 address block and operates it on STNET.
2403:4440::/322. Address Design Concept
The design allows addresses to be aggregated per campus, so each campus can reach external networks via the optimal route.
| Campus | Address Block |
|---|---|
| Ookayama Campus | 2403:4440:0040::/44 |
| Suzukakedai Campus | 2403:4440:0050::/44 |
| Tamachi Campus | 2403:4440:0060::/44 |
3. Subnet Address Scheme
Addresses within each campus are allocated according to the following rule.
2403:4440:00CX:ZZZZ::/64| Field | Meaning | Values |
|---|---|---|
| C | Campus ID | 4 = Ookayama, 5 = Suzukakedai, 6 = Tamachi |
| X | Purpose | 0 = Regular use (per organization), 1 = Project use |
| ZZZZ | Subnet ID | 0–4094: VLAN number (NOC internal); 5000–ffff: per-organization use |
4. Per-Organization Address Ranges
For regular use (X = 0), the subnet IDs (ZZZZ) per organization are as follows.
* Subject to change due to organizational restructuring.
| Organization | Subnet ID (ZZZZ) |
|---|---|
| School of Science | 5xxx |
| School of Engineering | 6xxx |
| School of Materials and Chemical Technology | 7xxx |
| School of Computing | 8xxx |
| School of Life Science and Technology | 9xxx |
| School of Environment and Society | axxx |
| Institute for Liberal Arts | bxxx |
| Institute of Innovative Research | cxxx |
| Research Centers and Common Education Organizations | dxxx |
| Common Support Organizations (including the Library) | exxx |
| Administration | fxxx |
5. IPv6 Address Usage Rules
| Item | Description |
|---|---|
| ▶ Recommended: prefix length /64 | For IPv6, we recommend operating all subnets with /64. |
| ▶ Acceptance of subnets with a prefix length longer than /64 | STNET also accepts routes longer than /64 (e.g., /96), but please consult the NOC in advance. |
| ▶ Notes on subnets with a prefix length longer than /64 | With subnets longer than /64, some devices may be unable to connect. In that case, please design and operate them under the responsibility of your unit. |
6. Other Address Blocks
The following address blocks are managed individually for specific purposes or organizations.
| Address Block | Purpose |
|---|---|
| 2403:4440:00ff::/48 | TSUBAME |
| 2403:4440:0100::/48 | Science Tokyo High School of Science and Technology |
| 2403:4440:ffff::/48 | IPv6 experimental service (no longer accepted) |
For IPv6 address applications and inquiries, please contact the NOC (Center for Information Infrastructure).
Mail: apply(at)noc.cii.isct.ac.jp * Please replace (at) with @.