diff --git a/src/net/offline_fluereflows.rs b/src/net/offline_fluereflows.rs
index 4385ded..72c08d5 100644
--- a/src/net/offline_fluereflows.rs
+++ b/src/net/offline_fluereflows.rs
@@ -1,4 +1,4 @@
-use std::{collections::HashMap, fs, path::Path, time::Instant};
+use std::{collections::{HashMap, BTreeMap}, fs, path::Path, time::Instant};
 
 use crate::{
     net::{
@@ -34,7 +34,6 @@ pub async fn fluereflow_fileparse(arg: Args) -> Result<(), FluereError> {
     };
 
     let start = Instant::now();
-    // let file_path = cur_time_file(csv_file.as_str(), file_dir, ".csv");
     let file_noext = format!(
         "{}_converted.csv",
         Path::new(&file_name)
@@ -45,10 +44,9 @@ pub async fn fluereflow_fileparse(arg: Args) -> Result<(), FluereError> {
     let output_file_path = format!("{}/{}", file_dir, file_noext);
     let file = fs::File::create(output_file_path.clone()).unwrap();
 
-    //let mut wtr = csv::Writer::from_writer(file);
-
     let mut records: Vec<FluereRecord> = Vec::new();
     let mut active_flow: HashMap<Key, FluereRecord> = HashMap::new();
+    let mut flow_expirations: BTreeMap<u64, Vec<Key>> = BTreeMap::new();
 
     info!("Converting file: {}", file_name);
 
@@ -56,6 +54,7 @@ pub async fn fluereflow_fileparse(arg: Args) -> Result<(), FluereError> {
 
     while let Ok(packet) = cap.next_packet() {
         trace!("Parsing packet");
+
         let (mut key_value, mut reverse_key) = match parse_keys(packet.clone()) {
             Ok(keys) => keys,
             Err(_) => continue,
@@ -73,24 +72,41 @@ pub async fn fluereflow_fileparse(arg: Args) -> Result<(), FluereError> {
                 continue;
             }
         };
+
+        // Define `packet_time` before any usage
+        let packet_time = parse_microseconds(
+            packet.header.ts.tv_sec as u64,
+            packet.header.ts.tv_usec as u64,
+        );
+
         let flags = TcpFlags::new(raw_flags);
-        //pushing packet in to active_flows if it is not present
+        // Pushing packet into active_flows if it is not present
         let is_reverse = match active_flow.get(&key_value) {
             None => match active_flow.get(&reverse_key) {
                 None => {
-                    // if the protocol is TCP, check if is a syn packet
+                    // If the protocol is TCP, check if it's a SYN packet
                     if flowdata.prot == 6 {
                         if flags.syn > 0 {
+                            let expiration_time = packet_time + (flow_timeout * 1_000); // Convert milliseconds to microseconds
+                            flow_expirations
+                                .entry(expiration_time)
+                                .or_insert_with(Vec::new)
+                                .push(key_value.clone());
                             active_flow.insert(key_value, flowdata);
 
-                            trace!("flow established");
+                            trace!("Flow established");
                         } else {
                             continue;
                         }
                     } else {
+                        let expiration_time = packet_time + (flow_timeout * 1_000); // Convert milliseconds to microseconds
+                        flow_expirations
+                            .entry(expiration_time)
+                            .or_insert_with(Vec::new)
+                            .push(key_value.clone());
                         active_flow.insert(key_value, flowdata);
 
-                        trace!("flow established");
+                        trace!("Flow established");
                     }
 
                     false
@@ -100,14 +116,9 @@ pub async fn fluereflow_fileparse(arg: Args) -> Result<(), FluereError> {
             Some(_) => false,
         };
 
-        let time = parse_microseconds(
-            packet.header.ts.tv_sec as u64,
-            packet.header.ts.tv_usec as u64,
-        );
         let pkt = flowdata.min_pkt;
         let ttl = flowdata.min_ttl;
-        //println!("active flows: {:?}", active_flow.len());
-        //println!("current inputed flow{:?}", active_flow.get(&key_value).unwrap());
+
         let flow_key = if is_reverse { &reverse_key } else { &key_value };
         if let Some(flow) = active_flow.get_mut(flow_key) {
             let update_key = UDFlowKey {
@@ -115,7 +126,7 @@ pub async fn fluereflow_fileparse(arg: Args) -> Result<(), FluereError> {
                 pkt,
                 ttl,
                 flags,
-                time,
+                time: packet_time, // Use the correct variable here
             };
 
             update_flow(flow, is_reverse, update_key);
@@ -126,27 +137,29 @@ pub async fn fluereflow_fileparse(arg: Args) -> Result<(), FluereError> {
             );
 
             if flags.fin == 1 || flags.rst == 1 {
-                trace!("flow finished");
-                trace!("flow data: {:?}", flow);
+                trace!("Flow finished");
+                trace!("Flow data: {:?}", flow);
                 records.push(*flow);
                 active_flow.remove(flow_key);
             }
         }
 
-        // Before processing a new packet, check for and handle expired flows
-        let mut expired_flows = Vec::new();
-        for (key, flow) in active_flow.iter() {
-            if flow_timeout > 0 && time > (flow.last + (flow_timeout * 1000)) {
-                // Assuming flow.last is in microseconds
-                trace!("flow expired");
-                trace!("flow data: {:?}", flow);
-                records.push(*flow);
-                expired_flows.push(*key);
+        // Remove expired flows before processing the next packet
+        let current_time = packet_time;
+        let expired_times: Vec<u64> = flow_expirations
+            .range(..=current_time)
+            .map(|(&time, _)| time)
+            .collect();
+
+        for expiration_time in expired_times {
+            if let Some(keys) = flow_expirations.remove(&expiration_time) {
+                for key in keys {
+                    if let Some(flow) = active_flow.remove(&key) {
+                        records.push(flow);
+                    }
+                }
             }
         }
-
-        // Remove expired flows from the active flows map
-        active_flow.retain(|key, _| !expired_flows.contains(key));
     }
     bar.finish();
     info!("Converted in {:?}", start.elapsed());
@@ -156,6 +169,7 @@ pub async fn fluereflow_fileparse(arg: Args) -> Result<(), FluereError> {
     for (_key, flow) in active_flow.clone().iter() {
         records.push(*flow);
     }
+    
     let tasks = task::spawn(async {
         fluere_exporter(records, file).await;
     });
@@ -163,7 +177,7 @@ pub async fn fluereflow_fileparse(arg: Args) -> Result<(), FluereError> {
     let result = tasks.await;
     info!("Export {} result: {:?}", output_file_path, result);
 
-    info!("Active flow {:?}", ac_flow_cnt);
-    info!("Ended flow {:?}", ended_flow_cnt);
+    info!("Active flows: {:?}", ac_flow_cnt);
+    info!("Ended flows: {:?}", ended_flow_cnt);
     Ok(())
-}
+}
\ No newline at end of file