diff --git a/docs/root/api-docs/xds_protocol.rst b/docs/root/api-docs/xds_protocol.rst index 71c5f646627bb..2f8873f7c7b47 100644 --- a/docs/root/api-docs/xds_protocol.rst +++ b/docs/root/api-docs/xds_protocol.rst @@ -763,6 +763,10 @@ is present for debugging purposes only. - As an ACK or NACK response to a previous :ref:`DeltaDiscoveryResponse `. In this case the :ref:`response_nonce ` is set to the nonce value in the Response. ACK or NACK is determined by the absence or presence of :ref:`error_detail `. - Spontaneous :ref:`DeltaDiscoveryRequests ` from the client. This can be done to dynamically add or remove elements from the tracked :ref:`resource_names ` set. In this case :ref:`response_nonce ` must be omitted. +Note that while a :ref:`response_nonce ` may +be set on the request, the server must honor changes to the subscription state even if the nonce is stale. The nonce +may be used to correlate an ack/nack with a server response, but should *not* be used to reject stale requests. + In this first example the client connects and receives a first update that it ACKs. The second update fails and the client NACKs the update. Later the xDS client spontaneously requests the "wc" resource.