3.1.5.6 Receiving a New ROUTE_ENTRY

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After a ROUTE_ENTRY message has been extracted from a received message, the receiving node MUST follow these steps to submit it to the cache for inclusion. If the PortNumber field of the ROUTE_ENTRY message is less than 1024, the entry MUST be ignored.

Otherwise, the node MUST attempt to add the ROUTE_ENTRY message to the Pending Route Entry Add List element, with the NeedCpa field set to false. If it cannot be added, the ROUTE_ENTRY message MUST be ignored.

The ROUTE_ENTRY message MUST then be tested for return routability by composing an INQUIRE message with the Validate Key field set to the key in the ROUTE_ENTRY message and FieldId3 set to 0x0093 (NONCE). The node MUST then select one of the addresses included in the ROUTE_ENTRY message, using the algorithm in [RFC3484] section 6, and send the INQUIRE message to the selected address, using the port indicated in the ROUTE_ENTRY message.

The node MUST then set InquireMessageId to the MessageID of the INQUIRE message sent, in the entry added to the Pending Route Entry Add List element.