IKE header

["David Faucher" <dfaucher@lucent.com>]

Section 5.1 of draft-ietf-ipsec-ikev2-03.txt
describes the IKE header states

- Recipient SPI MUST be zero for the first packet
of IKE_SA_init and MUST NOT be zero for any other
packet

- Sender SPI MUST NOT be zero.

    What about a node that is receiving packets
    with unknown SPIs? If it has no IKE-SA then
    what values would it place in the Recipient 
    and Sender SPI fields of an unprotected 
    informational containing a Notify payload?

- Flags (bit 3) MUST be set in messages sent by the 
original initiator of the IKE-SA and MUST be cleared
in messages sent by the original responder.

    Should "messages" be "requests" in the above
    statement? And MUST a response contain the value
    that was received in the request?

The term "original initiator" and "original responder" 
are seen throughout the document without having been
defined. Is it safe to assume that they are referring
to the role that a node played during the establishment
of the original IKE-SA? Would these change if the original
responder initiated a rekey of the IKE-SA?

David