5.10. Router Key
5.10 Router Key
0 8 16 24 31
.-------------------------------------------.
| Protocol | PDU | | |
| Version | Type | Flags | zero |
| 1 | 9 | | |
+-------------------------------------------+
| |
| Length |
| |
+-------------------------------------------+
| |
+--- ---+
| Subject Key Identifier |
+--- ---+
| |
+--- ---+
| (20 octets) |
+--- ---+
| |
+-------------------------------------------+
| |
| AS Number |
| |
+-------------------------------------------+
| |
| Subject Public Key Info |
| |
`-------------------------------------------'
The lowest-order bit of the Flags field is 1 for an announcement and 0 for a withdrawal.
The cache server MUST ensure that it has told the router client to have one and only one Router Key PDU for a unique {SKI, ASN, Subject Public Key} at any one point in time. Should the router client receive a Router Key PDU with a {SKI, ASN, Subject Public Key} identical to one it already has active, it SHOULD raise a Duplicate Announcement Received error.
Note that a particular ASN may appear in multiple Router Key PDUs with different Subject Public Key values, while a particular Subject Public Key value may appear in multiple Router Key PDUs with different ASNs. In the interest of keeping the announcement and withdrawal semantics as simple as possible for the router, this protocol makes no attempt to compress either of these cases.
Also note that it is possible, albeit very unlikely, for multiple distinct Subject Public Key values to hash to the same SKI. For this reason, implementations MUST compare Subject Public Key values as well as SKIs when detecting duplicate PDUs.