202.43.16.0/21
At a glance
Addresses
/21 block
Visibility
79 of 80 vantage points
RPKI
Registry
JPAllocated 7th January 2004
AS paths to this prefix
All pathsOne observed path, hop by hop, from the origin out to London, UK.
Seen from London, UK
- Peer of AS4721seen on 12,860 paths from 141 vantage points
- Peer of AS9824seen on 27,145 paths from 86 vantage points
- Peer of AS2497seen on 57,827 paths from 55 vantage points
- Peer of AS1299seen on 403,291 paths from 2 vantage points
SE
AEOne path, hop by hop, from the origin outward to the vantage point that saw it. Counts beside each step are how often we see that pair adjacent anywhere in the table, not how often this path was used — BGP carries no traffic figures.
Every path we see
- Singapore472198241299132337This path
- Oregon, US47219824693920130This path
- London, UK47219824249712998529Shown above
- Sao Paulo4721982425163356266213This path
- Amsterdam472198242516325734549213151This path
Each row is one path genuinely present in the routing table at our last snapshot, read outward from the origin to the vantage point that saw it. Open a row to follow that one path hop by hop. A heavier line in the graph means more vantage points reach the prefix that same way.
Route visibility
99%
Seen by 79 of 80 full-feed vantage points
Globally propagatedObserved at 5 of our collectors.
What this percentage counts
The denominator counts only full-feed peers — peers carrying a substantially complete routing table at the moment of the snapshot. IXP route-server peers usually feed partial tables and are excluded, because including them would make a normally propagated prefix look as though half the internet could not see it.
It measures how widely an announcement has spread across the networks we can observe. It says nothing about whether the prefix is reachable from any particular place, or how it performs.
Registry and RPKI
- RIR
- APNIC — Asia-Pacific
- Country
- Japan
- Allocated
- 7th January 2004
- Allocation block
- 202.43.16.0/20
- Status
- allocated
- Origin validation
- Valid
A ROA exists that authorises this origin AS to announce this prefix at this length.
Prefix hierarchy
Announcements above, below and beside this one in the real routing table.
Left to right is specificity: a shorter mask covering more address space, then this prefix, then the announcements carved out inside it. Only the first few of each are drawn — the tables below list them all.
Covering announcements
| Prefix | Addresses | Origin | Visibility |
|---|---|---|---|
| 202.43.16.0/20 | 4.1k | AS4721JCOM Co., Ltd. | 79/80 |
More specific announcements
Nothing inside this block is announced separately.
Sibling prefixes
| Prefix | Addresses | Origin | Visibility |
|---|---|---|---|
| 202.43.24.0/21 | 2k | AS4721JCOM Co., Ltd. | 79/80 |
History
- AS472112th August 2026 — present
Why these dates start where they do
A first-seen date is the first time we saw that origin, not the first time it appeared in BGP. Our history is forward-only with no backfill, so it says nothing about the period before we started collecting — treat the earliest dates with suspicion.
Open 202.43.16.0/21 in the calculator/21 reference
Routing data derived from RouteViews MRT archives and public registry data.