deltaLog.Debugf("ADS:%s: REQ %s Expired nonce received %s, sent %s", stype,
			con.ID(), request.ResponseNonce, previousInfo.NonceSent)
		xds.ExpiredNonce.With(typeTag.Value(v3.GetMetricType(request.TypeUrl))).Increment()
		return false
	}
	// If it comes here, that means nonce match. This an ACK. We should record
	// the ack details and respond if there is a change in resource names.