5.2. Serial Notify

5.2 Serial Notify

The cache notifies the router that the cache has new data.

The Session ID reassures the router that the Serial Numbers are commensurate, i.e., the cache session has not been changed.

Upon receipt of a Serial Notify PDU, the router MAY issue an immediate Serial Query (Section 5.3) or Reset Query (Section 5.4) without waiting for the Refresh Interval timer (see Section 6) to expire.

Serial Notify is the only message that the cache can send that is not in response to a message from the router.

If the router receives a Serial Notify PDU during the initial startup period where the router and cache are still negotiating to agree on a protocol version, the router MUST simply ignore the Serial Notify PDU, even if the Serial Notify PDU is for an unexpected protocol version. See Section 7 for details.

0          8          16         24        31
.-------------------------------------------.
| Protocol |   PDU    |                     |
| Version  |   Type   |     Session ID      |
|    1     |    0     |                     |
+-------------------------------------------+
|                                           |
|                Length=12                  |
|                                           |
+-------------------------------------------+
|                                           |
|               Serial Number               |
|                                           |
`-------------------------------------------'

5.2 Serial Notify​

5.2 Serial Notify