diff --git a/Cargo.lock b/Cargo.lock
index 3c6d7572..1c4413ae 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1112,18 +1112,6 @@ dependencies = [
  "thiserror",
 ]
 
-[[package]]
-name = "deprecate-until"
-version = "0.1.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7a3767f826efbbe5a5ae093920b58b43b01734202be697e1354914e862e8e704"
-dependencies = [
- "proc-macro2",
- "quote",
- "semver",
- "syn 2.0.48",
-]
-
 [[package]]
 name = "deranged"
 version = "0.3.11"
@@ -1300,8 +1288,8 @@ dependencies = [
  "network-interface",
  "nix 0.27.1",
  "once_cell",
- "pathfinding",
  "percent-encoding",
+ "petgraph",
  "pin-project-lite",
  "pnet",
  "postcard",
@@ -2342,15 +2330,6 @@ dependencies = [
  "cfg-if",
 ]
 
-[[package]]
-name = "integer-sqrt"
-version = "0.1.5"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "276ec31bcb4a9ee45f58bec6f9ec700ae4cf4f4f8f2fa7e06cb406bd5ffdd770"
-dependencies = [
- "num-traits",
-]
-
 [[package]]
 name = "ioctl-sys"
 version = "0.8.0"
@@ -3225,21 +3204,6 @@ version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8835116a5c179084a830efb3adc117ab007512b535bc1a21c991d3b32a6b44dd"
 
-[[package]]
-name = "pathfinding"
-version = "4.9.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f0a21c30f03223ae4a4c892f077b3189133689b8a659a84372f8422384ce94c9"
-dependencies = [
- "deprecate-until",
- "fixedbitset",
- "indexmap 2.2.6",
- "integer-sqrt",
- "num-traits",
- "rustc-hash",
- "thiserror",
-]
-
 [[package]]
 name = "pbkdf2"
 version = "0.11.0"
@@ -3270,9 +3234,9 @@ checksum = "e3148f5046208a5d56bcfc03053e3ca6334e51da8dfb19b6cdc8b306fae3283e"
 
 [[package]]
 name = "petgraph"
-version = "0.6.4"
+version = "0.6.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e1d3afd2628e69da2be385eb6f2fd57c8ac7977ceeff6dc166ff1657b0e386a9"
+checksum = "b4c5cc86750666a3ed20bdaf5ca2a0344f9c67674cae0515bec2da16fbaa47db"
 dependencies = [
  "fixedbitset",
  "indexmap 2.2.6",
diff --git a/easytier/Cargo.toml b/easytier/Cargo.toml
index 15875a71..09add658 100644
--- a/easytier/Cargo.toml
+++ b/easytier/Cargo.toml
@@ -137,7 +137,7 @@ async-recursion = "1.0.5"
 network-interface = "1.1.1"
 
 # for ospf route
-pathfinding = "4.9.1"
+petgraph = "0.6.5"
 
 # for encryption
 boringtun = { git = "https://github.com/EasyTier/boringtun.git", optional = true, rev = "449204c" }
diff --git a/easytier/proto/cli.proto b/easytier/proto/cli.proto
index bbc08e02..675093d8 100644
--- a/easytier/proto/cli.proto
+++ b/easytier/proto/cli.proto
@@ -117,16 +117,8 @@ service ConnectorManageRpc {
     rpc ManageConnector (ManageConnectorRequest) returns (ManageConnectorResponse);
 }
 
-enum LatencyLevel {
-    VeryLow = 0;
-    Low = 1;
-    Normal = 2;
-    High = 3;
-    VeryHigh = 4;
-}
-
 message DirectConnectedPeerInfo {
-    LatencyLevel latency_level = 2;
+    int32 latency_ms = 1;
 }
 
 message PeerInfoForGlobalMap {
diff --git a/easytier/src/common/config.rs b/easytier/src/common/config.rs
index 9604e373..76c1dd73 100644
--- a/easytier/src/common/config.rs
+++ b/easytier/src/common/config.rs
@@ -150,6 +150,8 @@ pub struct Flags {
     pub enable_ipv6: bool,
     #[derivative(Default(value = "1420"))]
     pub mtu: u16,
+    #[derivative(Default(value = "true"))]
+    pub latency_first: bool,
 }
 
 #[derive(Debug, Clone, Deserialize, Serialize, PartialEq)]
diff --git a/easytier/src/easytier-cli.rs b/easytier/src/easytier-cli.rs
index 44dc2230..97541ba2 100644
--- a/easytier/src/easytier-cli.rs
+++ b/easytier/src/easytier-cli.rs
@@ -331,13 +331,7 @@ async fn main() -> Result<(), Error> {
                 let direct_peers = v
                     .direct_peers
                     .iter()
-                    .map(|(k, v)| {
-                        format!(
-                            "{}:{:?}",
-                            k,
-                            LatencyLevel::try_from(v.latency_level).unwrap()
-                        )
-                    })
+                    .map(|(k, v)| format!("{}: {:?}ms", k, v.latency_ms,))
                     .collect::<Vec<_>>();
                 table_rows.push(PeerCenterTableItem {
                     node_id: node_id.to_string(),
diff --git a/easytier/src/easytier-core.rs b/easytier/src/easytier-core.rs
index 721b4768..ba7ec006 100644
--- a/easytier/src/easytier-core.rs
+++ b/easytier/src/easytier-core.rs
@@ -97,10 +97,6 @@ struct Cli {
                                 "wg://0.0.0.0:11011".to_string()])]
     listeners: Vec<String>,
 
-    /// specify the linux network namespace, default is the root namespace
-    #[arg(long)]
-    net_ns: Option<String>,
-
     #[arg(long, help = "console log level", 
         value_parser = clap::builder::PossibleValuesParser::new(["trace", "debug", "info", "warn", "error", "off"]))]
     console_log_level: Option<String>,
@@ -122,13 +118,6 @@ struct Cli {
     )]
     instance_name: String,
 
-    #[arg(
-        short = 'd',
-        long,
-        help = "instance uuid to identify this vpn node in whole vpn network example: 123e4567-e89b-12d3-a456-426614174000"
-    )]
-    instance_id: Option<String>,
-
     #[arg(
         long,
         help = "url that defines the vpn portal, allow other vpn clients to connect.
@@ -163,6 +152,13 @@ and the vpn client is in network of 10.14.14.0/24"
         help = "mtu of the TUN device, default is 1420 for non-encryption, 1400 for encryption"
     )]
     mtu: Option<u16>,
+
+    #[arg(
+        long,
+        help = "path to the log file, if not set, will print to stdout",
+        default_value = "false"
+    )]
+    latency_first: bool,
 }
 
 impl From<Cli> for TomlConfigLoader {
@@ -188,7 +184,6 @@ impl From<Cli> for TomlConfigLoader {
             cli.network_secret.clone(),
         ));
 
-        cfg.set_netns(cli.net_ns.clone());
         if let Some(ipv4) = &cli.ipv4 {
             cfg.set_ipv4(
                 ipv4.parse()
@@ -307,6 +302,7 @@ impl From<Cli> for TomlConfigLoader {
         }
         f.enable_encryption = !cli.disable_encryption;
         f.enable_ipv6 = !cli.disable_ipv6;
+        f.latency_first = cli.latency_first;
         if let Some(mtu) = cli.mtu {
             f.mtu = mtu;
         }
diff --git a/easytier/src/instance/instance.rs b/easytier/src/instance/instance.rs
index 07ea9124..7ad1e918 100644
--- a/easytier/src/instance/instance.rs
+++ b/easytier/src/instance/instance.rs
@@ -1,6 +1,7 @@
 use std::borrow::BorrowMut;
 use std::net::Ipv4Addr;
 use std::pin::Pin;
+use std::sync::atomic::{AtomicBool, Ordering};
 use std::sync::{Arc, Weak};
 
 use anyhow::Context;
@@ -44,6 +45,8 @@ struct IpProxy {
     tcp_proxy: Arc<TcpProxy>,
     icmp_proxy: Arc<IcmpProxy>,
     udp_proxy: Arc<UdpProxy>,
+    global_ctx: ArcGlobalCtx,
+    started: Arc<AtomicBool>,
 }
 
 impl IpProxy {
@@ -57,10 +60,17 @@ impl IpProxy {
             tcp_proxy,
             icmp_proxy,
             udp_proxy,
+            global_ctx,
+            started: Arc::new(AtomicBool::new(false)),
         })
     }
 
     async fn start(&self) -> Result<(), Error> {
+        if self.global_ctx.get_proxy_cidrs().is_empty() || self.started.load(Ordering::Relaxed) {
+            return Ok(());
+        }
+
+        self.started.store(true, Ordering::Relaxed);
         self.tcp_proxy.start().await?;
         self.icmp_proxy.start().await?;
         self.udp_proxy.start().await?;
@@ -297,11 +307,16 @@ impl Instance {
             self.get_global_ctx(),
             self.get_peer_manager(),
         )?);
-        self.ip_proxy.as_ref().unwrap().start().await?;
+        self.run_ip_proxy().await?;
 
         self.udp_hole_puncher.lock().await.run().await?;
 
         self.peer_center.init().await;
+        let route_calc = self.peer_center.get_cost_calculator();
+        self.peer_manager
+            .get_route()
+            .set_route_cost_fn(route_calc)
+            .await;
 
         self.add_initial_peers().await?;
 
@@ -312,6 +327,14 @@ impl Instance {
         Ok(())
     }
 
+    pub async fn run_ip_proxy(&mut self) -> Result<(), Error> {
+        if self.ip_proxy.is_none() {
+            return Err(anyhow::anyhow!("ip proxy not enabled.").into());
+        }
+        self.ip_proxy.as_ref().unwrap().start().await?;
+        Ok(())
+    }
+
     pub async fn run_vpn_portal(&mut self) -> Result<(), Error> {
         if self.global_ctx.get_vpn_portal_cidr().is_none() {
             return Err(anyhow::anyhow!("vpn portal cidr not set.").into());
diff --git a/easytier/src/peer_center/instance.rs b/easytier/src/peer_center/instance.rs
index 50ca5a6f..85f8208b 100644
--- a/easytier/src/peer_center/instance.rs
+++ b/easytier/src/peer_center/instance.rs
@@ -1,24 +1,23 @@
 use std::{
-    collections::hash_map::DefaultHasher,
-    hash::{Hash, Hasher},
-    sync::{
-        atomic::{AtomicBool, Ordering},
-        Arc,
-    },
-    time::{Duration, SystemTime},
+    collections::BTreeSet,
+    sync::Arc,
+    time::{Duration, Instant, SystemTime},
 };
 
 use crossbeam::atomic::AtomicCell;
 use futures::Future;
-use tokio::{
-    sync::{Mutex, RwLock},
-    task::JoinSet,
-};
+use std::sync::RwLock;
+use tokio::sync::Mutex;
+use tokio::task::JoinSet;
 use tracing::Instrument;
 
 use crate::{
     common::PeerId,
-    peers::{peer_manager::PeerManager, rpc_service::PeerManagerRpcService},
+    peers::{
+        peer_manager::PeerManager,
+        route_trait::{RouteCostCalculator, RouteCostCalculatorInterface},
+        rpc_service::PeerManagerRpcService,
+    },
     rpc::{GetGlobalPeerMapRequest, GetGlobalPeerMapResponse},
 };
 
@@ -34,7 +33,8 @@ struct PeerCenterBase {
     lock: Arc<Mutex<()>>,
 }
 
-static SERVICE_ID: u32 = 5;
+// static SERVICE_ID: u32 = 5; for compatibility with the original code
+static SERVICE_ID: u32 = 50;
 
 struct PeridicJobCtx<T> {
     peer_mgr: Arc<PeerManager>,
@@ -132,7 +132,7 @@ impl PeerCenterBase {
 
 pub struct PeerCenterInstanceService {
     global_peer_map: Arc<RwLock<GlobalPeerMap>>,
-    global_peer_map_digest: Arc<RwLock<Digest>>,
+    global_peer_map_digest: Arc<AtomicCell<Digest>>,
 }
 
 #[tonic::async_trait]
@@ -141,7 +141,7 @@ impl crate::rpc::cli::peer_center_rpc_server::PeerCenterRpc for PeerCenterInstan
         &self,
         _request: tonic::Request<GetGlobalPeerMapRequest>,
     ) -> Result<tonic::Response<GetGlobalPeerMapResponse>, tonic::Status> {
-        let global_peer_map = self.global_peer_map.read().await.clone();
+        let global_peer_map = self.global_peer_map.read().unwrap().clone();
         Ok(tonic::Response::new(GetGlobalPeerMapResponse {
             global_peer_map: global_peer_map
                 .map
@@ -157,7 +157,8 @@ pub struct PeerCenterInstance {
 
     client: Arc<PeerCenterBase>,
     global_peer_map: Arc<RwLock<GlobalPeerMap>>,
-    global_peer_map_digest: Arc<RwLock<Digest>>,
+    global_peer_map_digest: Arc<AtomicCell<Digest>>,
+    global_peer_map_update_time: Arc<AtomicCell<Instant>>,
 }
 
 impl PeerCenterInstance {
@@ -166,7 +167,8 @@ impl PeerCenterInstance {
             peer_mgr: peer_mgr.clone(),
             client: Arc::new(PeerCenterBase::new(peer_mgr.clone())),
             global_peer_map: Arc::new(RwLock::new(GlobalPeerMap::new())),
-            global_peer_map_digest: Arc::new(RwLock::new(Digest::default())),
+            global_peer_map_digest: Arc::new(AtomicCell::new(Digest::default())),
+            global_peer_map_update_time: Arc::new(AtomicCell::new(Instant::now())),
         }
     }
 
@@ -179,12 +181,14 @@ impl PeerCenterInstance {
     async fn init_get_global_info_job(&self) {
         struct Ctx {
             global_peer_map: Arc<RwLock<GlobalPeerMap>>,
-            global_peer_map_digest: Arc<RwLock<Digest>>,
+            global_peer_map_digest: Arc<AtomicCell<Digest>>,
+            global_peer_map_update_time: Arc<AtomicCell<Instant>>,
         }
 
         let ctx = Arc::new(Ctx {
             global_peer_map: self.global_peer_map.clone(),
             global_peer_map_digest: self.global_peer_map_digest.clone(),
+            global_peer_map_update_time: self.global_peer_map_update_time.clone(),
         });
 
         self.client
@@ -193,10 +197,7 @@ impl PeerCenterInstance {
                 rpc_ctx.deadline = SystemTime::now() + Duration::from_secs(3);
 
                 let ret = client
-                    .get_global_peer_map(
-                        rpc_ctx,
-                        ctx.job_ctx.global_peer_map_digest.read().await.clone(),
-                    )
+                    .get_global_peer_map(rpc_ctx, ctx.job_ctx.global_peer_map_digest.load())
                     .await?;
 
                 let Ok(resp) = ret else {
@@ -217,10 +218,13 @@ impl PeerCenterInstance {
                     resp.digest
                 );
 
-                *ctx.job_ctx.global_peer_map.write().await = resp.global_peer_map;
-                *ctx.job_ctx.global_peer_map_digest.write().await = resp.digest;
+                *ctx.job_ctx.global_peer_map.write().unwrap() = resp.global_peer_map;
+                ctx.job_ctx.global_peer_map_digest.store(resp.digest);
+                ctx.job_ctx
+                    .global_peer_map_update_time
+                    .store(Instant::now());
 
-                Ok(10000)
+                Ok(5000)
             })
             .await;
     }
@@ -228,67 +232,53 @@ impl PeerCenterInstance {
     async fn init_report_peers_job(&self) {
         struct Ctx {
             service: PeerManagerRpcService,
-            need_send_peers: AtomicBool,
-            last_report_peers: Mutex<PeerInfoForGlobalMap>,
+
+            last_report_peers: Mutex<BTreeSet<PeerId>>,
+
             last_center_peer: AtomicCell<PeerId>,
+            last_report_time: AtomicCell<Instant>,
         }
         let ctx = Arc::new(Ctx {
             service: PeerManagerRpcService::new(self.peer_mgr.clone()),
-            need_send_peers: AtomicBool::new(true),
-            last_report_peers: Mutex::new(PeerInfoForGlobalMap::default()),
+            last_report_peers: Mutex::new(BTreeSet::new()),
             last_center_peer: AtomicCell::new(PeerId::default()),
+            last_report_time: AtomicCell::new(Instant::now()),
         });
 
         self.client
             .init_periodic_job(ctx, |client, ctx| async move {
                 let my_node_id = ctx.peer_mgr.my_peer_id();
+                let peers: PeerInfoForGlobalMap = ctx.job_ctx.service.list_peers().await.into();
+                let peer_list = peers.direct_peers.keys().map(|k| *k).collect();
+                let job_ctx = &ctx.job_ctx;
 
-                // if peers are not same in next 10 seconds, report peers to center server
-                let mut peers = PeerInfoForGlobalMap::default();
-                for _ in 1..10 {
-                    peers = ctx.job_ctx.service.list_peers().await.into();
-                    if ctx.center_peer.load() != ctx.job_ctx.last_center_peer.load() {
-                        // if center peer changed, report peers immediately
-                        break;
-                    }
-                    if peers == *ctx.job_ctx.last_report_peers.lock().await {
-                        return Ok(3000);
-                    }
-                    tokio::time::sleep(Duration::from_secs(2)).await;
+                // only report when:
+                // 1. center peer changed
+                // 2. last report time is more than 60 seconds
+                // 3. peers changed
+                if ctx.center_peer.load() == ctx.job_ctx.last_center_peer.load()
+                    && job_ctx.last_report_time.load().elapsed().as_secs() < 60
+                    && *job_ctx.last_report_peers.lock().await == peer_list
+                {
+                    return Ok(5000);
                 }
 
-                *ctx.job_ctx.last_report_peers.lock().await = peers.clone();
-                let mut hasher = DefaultHasher::new();
-                peers.hash(&mut hasher);
-
-                let peers = if ctx.job_ctx.need_send_peers.load(Ordering::Relaxed) {
-                    Some(peers)
-                } else {
-                    None
-                };
                 let mut rpc_ctx = tarpc::context::current();
                 rpc_ctx.deadline = SystemTime::now() + Duration::from_secs(3);
 
                 let ret = client
-                    .report_peers(
-                        rpc_ctx,
-                        my_node_id.clone(),
-                        peers,
-                        hasher.finish() as Digest,
-                    )
+                    .report_peers(rpc_ctx, my_node_id.clone(), peers)
                     .await?;
 
-                if matches!(ret.as_ref().err(), Some(Error::DigestMismatch)) {
-                    ctx.job_ctx.need_send_peers.store(true, Ordering::Relaxed);
-                    return Ok(0);
-                } else if ret.is_err() {
+                if ret.is_ok() {
+                    ctx.job_ctx.last_center_peer.store(ctx.center_peer.load());
+                    *ctx.job_ctx.last_report_peers.lock().await = peer_list;
+                    ctx.job_ctx.last_report_time.store(Instant::now());
+                } else {
                     tracing::error!("report peers to center server got error result: {:?}", ret);
-                    return Ok(500);
                 }
 
-                ctx.job_ctx.last_center_peer.store(ctx.center_peer.load());
-                ctx.job_ctx.need_send_peers.store(false, Ordering::Relaxed);
-                Ok(3000)
+                Ok(5000)
             })
             .await;
     }
@@ -299,15 +289,61 @@ impl PeerCenterInstance {
             global_peer_map_digest: self.global_peer_map_digest.clone(),
         }
     }
+
+    pub fn get_cost_calculator(&self) -> RouteCostCalculator {
+        struct RouteCostCalculatorImpl {
+            global_peer_map: Arc<RwLock<GlobalPeerMap>>,
+
+            global_peer_map_clone: GlobalPeerMap,
+
+            last_update_time: AtomicCell<Instant>,
+            global_peer_map_update_time: Arc<AtomicCell<Instant>>,
+        }
+
+        impl RouteCostCalculatorInterface for RouteCostCalculatorImpl {
+            fn calculate_cost(&self, src: PeerId, dst: PeerId) -> i32 {
+                let ret = self
+                    .global_peer_map_clone
+                    .map
+                    .get(&src)
+                    .and_then(|src_peer_info| src_peer_info.direct_peers.get(&dst))
+                    .and_then(|info| Some(info.latency_ms));
+                ret.unwrap_or(80)
+            }
+
+            fn begin_update(&mut self) {
+                let global_peer_map = self.global_peer_map.read().unwrap();
+                self.global_peer_map_clone = global_peer_map.clone();
+            }
+
+            fn end_update(&mut self) {
+                self.last_update_time
+                    .store(self.global_peer_map_update_time.load());
+            }
+
+            fn need_update(&self) -> bool {
+                self.last_update_time.load() < self.global_peer_map_update_time.load()
+            }
+        }
+
+        Box::new(RouteCostCalculatorImpl {
+            global_peer_map: self.global_peer_map.clone(),
+            global_peer_map_clone: GlobalPeerMap::new(),
+            last_update_time: AtomicCell::new(
+                self.global_peer_map_update_time.load() - Duration::from_secs(1),
+            ),
+            global_peer_map_update_time: self.global_peer_map_update_time.clone(),
+        })
+    }
 }
 
 #[cfg(test)]
 mod tests {
-    use std::ops::Deref;
-
     use crate::{
         peer_center::server::get_global_data,
-        peers::tests::{connect_peer_manager, create_mock_peer_manager, wait_route_appear},
+        peers::tests::{
+            connect_peer_manager, create_mock_peer_manager, wait_for_condition, wait_route_appear,
+        },
     };
 
     use super::*;
@@ -340,43 +376,64 @@ mod tests {
         let center_data = get_global_data(center_peer);
 
         // wait center_data has 3 records for 10 seconds
-        let now = std::time::Instant::now();
-        loop {
-            if center_data.read().await.global_peer_map.map.len() == 3 {
-                println!(
-                    "center data ready, {:#?}",
-                    center_data.read().await.global_peer_map
-                );
-                break;
-            }
-            if now.elapsed().as_secs() > 60 {
-                panic!("center data not ready");
-            }
-            tokio::time::sleep(Duration::from_millis(100)).await;
-        }
+        wait_for_condition(
+            || async {
+                if center_data.global_peer_map.len() == 4 {
+                    println!("center data {:#?}", center_data.global_peer_map);
+                    true
+                } else {
+                    false
+                }
+            },
+            Duration::from_secs(10),
+        )
+        .await;
 
         let mut digest = None;
         for pc in peer_centers.iter() {
             let rpc_service = pc.get_rpc_service();
-            let now = std::time::Instant::now();
-            while now.elapsed().as_secs() < 10 {
-                if rpc_service.global_peer_map.read().await.map.len() == 3 {
-                    break;
-                }
-                tokio::time::sleep(Duration::from_millis(100)).await;
-            }
-            assert_eq!(rpc_service.global_peer_map.read().await.map.len(), 3);
+            wait_for_condition(
+                || async { rpc_service.global_peer_map.read().unwrap().map.len() == 3 },
+                Duration::from_secs(10),
+            )
+            .await;
+
             println!("rpc service ready, {:#?}", rpc_service.global_peer_map);
 
             if digest.is_none() {
-                digest = Some(rpc_service.global_peer_map_digest.read().await.clone());
+                digest = Some(rpc_service.global_peer_map_digest.load());
             } else {
-                let v = rpc_service.global_peer_map_digest.read().await;
-                assert_eq!(digest.as_ref().unwrap(), v.deref());
+                let v = rpc_service.global_peer_map_digest.load();
+                assert_eq!(digest.unwrap(), v);
             }
+
+            let mut route_cost = pc.get_cost_calculator();
+            assert!(route_cost.need_update());
+
+            route_cost.begin_update();
+            assert!(
+                route_cost.calculate_cost(peer_mgr_a.my_peer_id(), peer_mgr_b.my_peer_id()) < 30
+            );
+            assert!(
+                route_cost.calculate_cost(peer_mgr_b.my_peer_id(), peer_mgr_a.my_peer_id()) < 30
+            );
+            assert!(
+                route_cost.calculate_cost(peer_mgr_b.my_peer_id(), peer_mgr_c.my_peer_id()) < 30
+            );
+            assert!(
+                route_cost.calculate_cost(peer_mgr_c.my_peer_id(), peer_mgr_b.my_peer_id()) < 30
+            );
+            assert!(
+                route_cost.calculate_cost(peer_mgr_c.my_peer_id(), peer_mgr_a.my_peer_id()) > 50
+            );
+            assert!(
+                route_cost.calculate_cost(peer_mgr_a.my_peer_id(), peer_mgr_c.my_peer_id()) > 50
+            );
+            route_cost.end_update();
+            assert!(!route_cost.need_update());
         }
 
-        let global_digest = get_global_data(center_peer).read().await.digest.clone();
+        let global_digest = get_global_data(center_peer).digest.load();
         assert_eq!(digest.as_ref().unwrap(), &global_digest);
     }
 }
diff --git a/easytier/src/peer_center/server.rs b/easytier/src/peer_center/server.rs
index 89a929f8..efa6029e 100644
--- a/easytier/src/peer_center/server.rs
+++ b/easytier/src/peer_center/server.rs
@@ -1,45 +1,48 @@
 use std::{
+    collections::BinaryHeap,
     hash::{Hash, Hasher},
     sync::Arc,
 };
 
+use crossbeam::atomic::AtomicCell;
 use dashmap::DashMap;
 use once_cell::sync::Lazy;
-use tokio::{sync::RwLock, task::JoinSet};
+use tokio::{task::JoinSet};
 
-use crate::common::PeerId;
+use crate::{common::PeerId, rpc::DirectConnectedPeerInfo};
 
 use super::{
     service::{GetGlobalPeerMapResponse, GlobalPeerMap, PeerCenterService, PeerInfoForGlobalMap},
     Digest, Error,
 };
 
-pub(crate) struct PeerCenterServerGlobalData {
-    pub global_peer_map: GlobalPeerMap,
-    pub digest: Digest,
-    pub update_time: std::time::Instant,
-    pub peer_update_time: DashMap<PeerId, std::time::Instant>,
+#[derive(Debug, Clone, PartialEq, PartialOrd, Ord, Eq, Hash)]
+pub(crate) struct SrcDstPeerPair {
+    src: PeerId,
+    dst: PeerId,
 }
 
-impl PeerCenterServerGlobalData {
-    fn new() -> Self {
-        PeerCenterServerGlobalData {
-            global_peer_map: GlobalPeerMap::new(),
-            digest: Digest::default(),
-            update_time: std::time::Instant::now(),
-            peer_update_time: DashMap::new(),
-        }
-    }
+#[derive(Debug, Clone)]
+pub(crate) struct PeerCenterInfoEntry {
+    info: DirectConnectedPeerInfo,
+    update_time: std::time::Instant,
+}
+
+#[derive(Default)]
+pub(crate) struct PeerCenterServerGlobalData {
+    pub(crate) global_peer_map: DashMap<SrcDstPeerPair, PeerCenterInfoEntry>,
+    pub(crate) peer_report_time: DashMap<PeerId, std::time::Instant>,
+    pub(crate) digest: AtomicCell<Digest>,
 }
 
 // a global unique instance for PeerCenterServer
-pub(crate) static GLOBAL_DATA: Lazy<DashMap<PeerId, Arc<RwLock<PeerCenterServerGlobalData>>>> =
+pub(crate) static GLOBAL_DATA: Lazy<DashMap<PeerId, Arc<PeerCenterServerGlobalData>>> =
     Lazy::new(DashMap::new);
 
-pub(crate) fn get_global_data(node_id: PeerId) -> Arc<RwLock<PeerCenterServerGlobalData>> {
+pub(crate) fn get_global_data(node_id: PeerId) -> Arc<PeerCenterServerGlobalData> {
     GLOBAL_DATA
         .entry(node_id)
-        .or_insert_with(|| Arc::new(RwLock::new(PeerCenterServerGlobalData::new())))
+        .or_insert_with(|| Arc::new(PeerCenterServerGlobalData::default()))
         .value()
         .clone()
 }
@@ -48,8 +51,6 @@ pub(crate) fn get_global_data(node_id: PeerId) -> Arc<RwLock<PeerCenterServerGlo
 pub struct PeerCenterServer {
     // every peer has its own server, so use per-struct dash map is ok.
     my_node_id: PeerId,
-    digest_map: DashMap<PeerId, Digest>,
-
     tasks: Arc<JoinSet<()>>,
 }
 
@@ -65,26 +66,32 @@ impl PeerCenterServer {
 
         PeerCenterServer {
             my_node_id,
-            digest_map: DashMap::new(),
-
             tasks: Arc::new(tasks),
         }
     }
 
     async fn clean_outdated_peer(my_node_id: PeerId) {
         let data = get_global_data(my_node_id);
-        let mut locked_data = data.write().await;
-        let now = std::time::Instant::now();
-        let mut to_remove = Vec::new();
-        for kv in locked_data.peer_update_time.iter() {
-            if now.duration_since(*kv.value()).as_secs() > 20 {
-                to_remove.push(*kv.key());
-            }
-        }
-        for peer_id in to_remove {
-            locked_data.global_peer_map.map.remove(&peer_id);
-            locked_data.peer_update_time.remove(&peer_id);
-        }
+        data.peer_report_time.retain(|_, v| {
+            std::time::Instant::now().duration_since(*v) < std::time::Duration::from_secs(180)
+        });
+        data.global_peer_map.retain(|_, v| {
+            std::time::Instant::now().duration_since(v.update_time)
+                < std::time::Duration::from_secs(180)
+        });
+    }
+
+    fn calc_global_digest(my_node_id: PeerId) -> Digest {
+        let data = get_global_data(my_node_id);
+        let mut hasher = std::collections::hash_map::DefaultHasher::new();
+        data.global_peer_map
+            .iter()
+            .map(|v| v.key().clone())
+            .collect::<BinaryHeap<_>>()
+            .into_sorted_vec()
+            .into_iter()
+            .for_each(|v| v.hash(&mut hasher));
+        hasher.finish()
     }
 }
 
@@ -95,39 +102,28 @@ impl PeerCenterService for PeerCenterServer {
         self,
         _: tarpc::context::Context,
         my_peer_id: PeerId,
-        peers: Option<PeerInfoForGlobalMap>,
-        digest: Digest,
+        peers: PeerInfoForGlobalMap,
     ) -> Result<(), Error> {
-        tracing::trace!("receive report_peers");
+        tracing::debug!("receive report_peers");
 
         let data = get_global_data(self.my_node_id);
-        let mut locked_data = data.write().await;
-        locked_data
-            .peer_update_time
+        data.peer_report_time
             .insert(my_peer_id, std::time::Instant::now());
 
-        let old_digest = self.digest_map.get(&my_peer_id);
-        // if digest match, no need to update
-        if let Some(old_digest) = old_digest {
-            if *old_digest == digest {
-                return Ok(());
-            }
+        for (peer_id, peer_info) in peers.direct_peers {
+            let pair = SrcDstPeerPair {
+                src: my_peer_id,
+                dst: peer_id,
+            };
+            let entry = PeerCenterInfoEntry {
+                info: peer_info,
+                update_time: std::time::Instant::now(),
+            };
+            data.global_peer_map.insert(pair, entry);
         }
 
-        if peers.is_none() {
-            return Err(Error::DigestMismatch);
-        }
-
-        self.digest_map.insert(my_peer_id, digest);
-        locked_data
-            .global_peer_map
-            .map
-            .insert(my_peer_id, peers.unwrap());
-
-        let mut hasher = std::collections::hash_map::DefaultHasher::new();
-        locked_data.global_peer_map.map.hash(&mut hasher);
-        locked_data.digest = hasher.finish() as Digest;
-        locked_data.update_time = std::time::Instant::now();
+        data.digest
+            .store(PeerCenterServer::calc_global_digest(self.my_node_id));
 
         Ok(())
     }
@@ -138,15 +134,26 @@ impl PeerCenterService for PeerCenterServer {
         digest: Digest,
     ) -> Result<Option<GetGlobalPeerMapResponse>, Error> {
         let data = get_global_data(self.my_node_id);
-        if digest == data.read().await.digest {
+        if digest == data.digest.load() && digest != 0 {
             return Ok(None);
         }
 
-        let data = get_global_data(self.my_node_id);
-        let locked_data = data.read().await;
+        let mut global_peer_map = GlobalPeerMap::new();
+        for item in data.global_peer_map.iter() {
+            let (pair, entry) = item.pair();
+            global_peer_map
+                .map
+                .entry(pair.src)
+                .or_insert_with(|| PeerInfoForGlobalMap {
+                    direct_peers: Default::default(),
+                })
+                .direct_peers
+                .insert(pair.dst, entry.info.clone());
+        }
+
         Ok(Some(GetGlobalPeerMapResponse {
-            global_peer_map: locked_data.global_peer_map.clone(),
-            digest: locked_data.digest,
+            global_peer_map,
+            digest: data.digest.load(),
         }))
     }
 }
diff --git a/easytier/src/peer_center/service.rs b/easytier/src/peer_center/service.rs
index 647d3aa7..e6d4d04e 100644
--- a/easytier/src/peer_center/service.rs
+++ b/easytier/src/peer_center/service.rs
@@ -5,39 +5,23 @@ use crate::{common::PeerId, rpc::DirectConnectedPeerInfo};
 use super::{Digest, Error};
 use crate::rpc::PeerInfo;
 
-pub type LatencyLevel = crate::rpc::cli::LatencyLevel;
-
-impl LatencyLevel {
-    pub const fn from_latency_ms(lat_ms: u32) -> Self {
-        if lat_ms < 10 {
-            LatencyLevel::VeryLow
-        } else if lat_ms < 50 {
-            LatencyLevel::Low
-        } else if lat_ms < 100 {
-            LatencyLevel::Normal
-        } else if lat_ms < 200 {
-            LatencyLevel::High
-        } else {
-            LatencyLevel::VeryHigh
-        }
-    }
-}
-
 pub type PeerInfoForGlobalMap = crate::rpc::cli::PeerInfoForGlobalMap;
 
 impl From<Vec<PeerInfo>> for PeerInfoForGlobalMap {
     fn from(peers: Vec<PeerInfo>) -> Self {
         let mut peer_map = BTreeMap::new();
         for peer in peers {
-            let min_lat = peer
+            let Some(min_lat) = peer
                 .conns
                 .iter()
                 .map(|conn| conn.stats.as_ref().unwrap().latency_us)
                 .min()
-                .unwrap_or(0);
+            else {
+                continue;
+            };
 
             let dp_info = DirectConnectedPeerInfo {
-                latency_level: LatencyLevel::from_latency_ms(min_lat as u32 / 1000) as i32,
+                latency_ms: std::cmp::max(1, (min_lat as u32 / 1000) as i32),
             };
 
             // sort conn info so hash result is stable
@@ -73,11 +57,7 @@ pub struct GetGlobalPeerMapResponse {
 pub trait PeerCenterService {
     // report center server which peer is directly connected to me
     // digest is a hash of current peer map, if digest not match, we need to transfer the whole map
-    async fn report_peers(
-        my_peer_id: PeerId,
-        peers: Option<PeerInfoForGlobalMap>,
-        digest: Digest,
-    ) -> Result<(), Error>;
+    async fn report_peers(my_peer_id: PeerId, peers: PeerInfoForGlobalMap) -> Result<(), Error>;
 
     async fn get_global_peer_map(digest: Digest)
         -> Result<Option<GetGlobalPeerMapResponse>, Error>;
diff --git a/easytier/src/peers/foreign_network_manager.rs b/easytier/src/peers/foreign_network_manager.rs
index f0b179b6..35ef2f84 100644
--- a/easytier/src/peers/foreign_network_manager.rs
+++ b/easytier/src/peers/foreign_network_manager.rs
@@ -29,6 +29,7 @@ use super::{
     peer_conn::PeerConn,
     peer_map::PeerMap,
     peer_rpc::{PeerRpcManager, PeerRpcManagerTransport},
+    route_trait::NextHopPolicy,
     PacketRecvChan, PacketRecvChanReceiver,
 };
 
@@ -66,7 +67,10 @@ impl ForeignNetworkManagerData {
             .get(&network_name)
             .ok_or_else(|| Error::RouteError(Some("no peer in network".to_string())))?
             .clone();
-        entry.peer_map.send_msg(msg, dst_peer_id).await
+        entry
+            .peer_map
+            .send_msg(msg, dst_peer_id, NextHopPolicy::LeastHop)
+            .await
     }
 
     fn get_peer_network(&self, peer_id: PeerId) -> Option<String> {
@@ -275,7 +279,10 @@ impl ForeignNetworkManager {
                     }
 
                     if let Some(entry) = data.get_network_entry(&from_network) {
-                        let ret = entry.peer_map.send_msg(packet_bytes, to_peer_id).await;
+                        let ret = entry
+                            .peer_map
+                            .send_msg(packet_bytes, to_peer_id, NextHopPolicy::LeastHop)
+                            .await;
                         if ret.is_err() {
                             tracing::error!("forward packet to peer failed: {:?}", ret.err());
                         }
diff --git a/easytier/src/peers/peer_manager.rs b/easytier/src/peers/peer_manager.rs
index b6fec0f4..e040d250 100644
--- a/easytier/src/peers/peer_manager.rs
+++ b/easytier/src/peers/peer_manager.rs
@@ -22,7 +22,9 @@ use tokio_util::bytes::Bytes;
 use crate::{
     common::{error::Error, global_ctx::ArcGlobalCtx, PeerId},
     peers::{
-        peer_conn::PeerConn, peer_rpc::PeerRpcManagerTransport, route_trait::RouteInterface,
+        peer_conn::PeerConn,
+        peer_rpc::PeerRpcManagerTransport,
+        route_trait::{NextHopPolicy, RouteInterface},
         PeerPacketFilter,
     },
     tunnel::{
@@ -73,7 +75,10 @@ impl PeerRpcManagerTransport for RpcTransport {
             .ok_or(Error::Unknown)?;
         let peers = self.peers.upgrade().ok_or(Error::Unknown)?;
 
-        if let Some(gateway_id) = peers.get_gateway_peer_id(dst_peer_id).await {
+        if let Some(gateway_id) = peers
+            .get_gateway_peer_id(dst_peer_id, NextHopPolicy::LeastHop)
+            .await
+        {
             tracing::trace!(
                 ?dst_peer_id,
                 ?gateway_id,
@@ -320,20 +325,33 @@ impl PeerManager {
         let my_peer_id = self.my_peer_id;
         let peers = self.peers.clone();
         let pipe_line = self.peer_packet_process_pipeline.clone();
+        let foreign_client = self.foreign_network_client.clone();
         let encryptor = self.encryptor.clone();
         self.tasks.lock().await.spawn(async move {
             log::trace!("start_peer_recv");
             while let Some(mut ret) = recv.next().await {
-                let Some(hdr) = ret.peer_manager_header() else {
+                let Some(hdr) = ret.mut_peer_manager_header() else {
                     tracing::warn!(?ret, "invalid packet, skip");
                     continue;
                 };
-                tracing::trace!(?hdr, ?ret, "peer recv a packet...");
+                tracing::trace!(?hdr, "peer recv a packet...");
                 let from_peer_id = hdr.from_peer_id.get();
                 let to_peer_id = hdr.to_peer_id.get();
                 if to_peer_id != my_peer_id {
+                    if hdr.forward_counter > 7 {
+                        tracing::warn!(?hdr, "forward counter exceed, drop packet");
+                        continue;
+                    }
+
+                    if hdr.forward_counter > 2 && hdr.is_latency_first() {
+                        tracing::trace!(?hdr, "set_latency_first false because too many hop");
+                        hdr.set_latency_first(false);
+                    }
+
+                    hdr.forward_counter += 1;
                     tracing::trace!(?to_peer_id, ?my_peer_id, "need forward");
-                    let ret = peers.send_msg(ret, to_peer_id).await;
+                    let ret =
+                        Self::send_msg_internal(&peers, &foreign_client, ret, to_peer_id).await;
                     if ret.is_err() {
                         tracing::error!(?ret, ?to_peer_id, ?from_peer_id, "forward packet error");
                     }
@@ -518,11 +536,31 @@ impl PeerManager {
         }
     }
 
+    fn get_next_hop_policy(is_first_latency: bool) -> NextHopPolicy {
+        if is_first_latency {
+            NextHopPolicy::LeastCost
+        } else {
+            NextHopPolicy::LeastHop
+        }
+    }
+
     pub async fn send_msg(&self, msg: ZCPacket, dst_peer_id: PeerId) -> Result<(), Error> {
-        if let Some(gateway) = self.peers.get_gateway_peer_id(dst_peer_id).await {
-            self.peers.send_msg_directly(msg, gateway).await
-        } else if self.foreign_network_client.has_next_hop(dst_peer_id) {
-            self.foreign_network_client.send_msg(msg, dst_peer_id).await
+        Self::send_msg_internal(&self.peers, &self.foreign_network_client, msg, dst_peer_id).await
+    }
+
+    async fn send_msg_internal(
+        peers: &Arc<PeerMap>,
+        foreign_network_client: &Arc<ForeignNetworkClient>,
+        msg: ZCPacket,
+        dst_peer_id: PeerId,
+    ) -> Result<(), Error> {
+        let policy =
+            Self::get_next_hop_policy(msg.peer_manager_header().unwrap().is_latency_first());
+
+        if let Some(gateway) = peers.get_gateway_peer_id(dst_peer_id, policy).await {
+            peers.send_msg_directly(msg, gateway).await
+        } else if foreign_network_client.has_next_hop(dst_peer_id) {
+            foreign_network_client.send_msg(msg, dst_peer_id).await
         } else {
             Err(Error::RouteError(None))
         }
@@ -564,6 +602,12 @@ impl PeerManager {
             .encrypt(&mut msg)
             .with_context(|| "encrypt failed")?;
 
+        let is_latency_first = self.global_ctx.get_flags().latency_first;
+        msg.mut_peer_manager_header()
+            .unwrap()
+            .set_latency_first(is_latency_first);
+        let next_hop_policy = Self::get_next_hop_policy(is_latency_first);
+
         let mut errs: Vec<Error> = vec![];
 
         let mut msg = Some(msg);
@@ -581,7 +625,11 @@ impl PeerManager {
                 .to_peer_id
                 .set(*peer_id);
 
-            if let Some(gateway) = self.peers.get_gateway_peer_id(*peer_id).await {
+            if let Some(gateway) = self
+                .peers
+                .get_gateway_peer_id(*peer_id, next_hop_policy.clone())
+                .await
+            {
                 if let Err(e) = self.peers.send_msg_directly(msg, gateway).await {
                     errs.push(e);
                 }
diff --git a/easytier/src/peers/peer_map.rs b/easytier/src/peers/peer_map.rs
index 821c9035..286b9d10 100644
--- a/easytier/src/peers/peer_map.rs
+++ b/easytier/src/peers/peer_map.rs
@@ -18,7 +18,7 @@ use crate::{
 use super::{
     peer::Peer,
     peer_conn::{PeerConn, PeerConnId},
-    route_trait::ArcRoute,
+    route_trait::{ArcRoute, NextHopPolicy},
     PacketRecvChan,
 };
 
@@ -94,18 +94,25 @@ impl PeerMap {
         Ok(())
     }
 
-    pub async fn get_gateway_peer_id(&self, dst_peer_id: PeerId) -> Option<PeerId> {
+    pub async fn get_gateway_peer_id(
+        &self,
+        dst_peer_id: PeerId,
+        policy: NextHopPolicy,
+    ) -> Option<PeerId> {
         if dst_peer_id == self.my_peer_id {
             return Some(dst_peer_id);
         }
 
-        if self.has_peer(dst_peer_id) {
+        if self.has_peer(dst_peer_id) && matches!(policy, NextHopPolicy::LeastHop) {
             return Some(dst_peer_id);
         }
 
         // get route info
         for route in self.routes.read().await.iter() {
-            if let Some(gateway_peer_id) = route.get_next_hop(dst_peer_id).await {
+            if let Some(gateway_peer_id) = route
+                .get_next_hop_with_policy(dst_peer_id, policy.clone())
+                .await
+            {
                 // for foreign network, gateway_peer_id may not connect to me
                 if self.has_peer(gateway_peer_id) {
                     return Some(gateway_peer_id);
@@ -116,8 +123,13 @@ impl PeerMap {
         None
     }
 
-    pub async fn send_msg(&self, msg: ZCPacket, dst_peer_id: PeerId) -> Result<(), Error> {
-        let Some(gateway_peer_id) = self.get_gateway_peer_id(dst_peer_id).await else {
+    pub async fn send_msg(
+        &self,
+        msg: ZCPacket,
+        dst_peer_id: PeerId,
+        policy: NextHopPolicy,
+    ) -> Result<(), Error> {
+        let Some(gateway_peer_id) = self.get_gateway_peer_id(dst_peer_id, policy).await else {
             return Err(Error::RouteError(Some(format!(
                 "peer map sengmsg no gateway for dst_peer_id: {}",
                 dst_peer_id
diff --git a/easytier/src/peers/peer_ospf_route.rs b/easytier/src/peers/peer_ospf_route.rs
index 59bdbf43..758bcb78 100644
--- a/easytier/src/peers/peer_ospf_route.rs
+++ b/easytier/src/peers/peer_ospf_route.rs
@@ -10,6 +10,11 @@ use std::{
 };
 
 use dashmap::DashMap;
+use petgraph::{
+    algo::{all_simple_paths, astar, dijkstra},
+    graph::NodeIndex,
+    Directed, Graph,
+};
 use serde::{Deserialize, Serialize};
 use tokio::{select, sync::Mutex, task::JoinSet};
 
@@ -19,7 +24,14 @@ use crate::{
     rpc::{NatType, StunInfo},
 };
 
-use super::{peer_rpc::PeerRpcManager, PeerPacketFilter};
+use super::{
+    peer_rpc::PeerRpcManager,
+    route_trait::{
+        DefaultRouteCostCalculator, NextHopPolicy, RouteCostCalculator,
+        RouteCostCalculatorInterface,
+    },
+    PeerPacketFilter,
+};
 
 static SERVICE_ID: u32 = 7;
 static UPDATE_PEER_INFO_PERIOD: Duration = Duration::from_secs(3600);
@@ -360,11 +372,15 @@ impl SyncedRouteInfo {
     }
 }
 
+type PeerGraph = Graph<PeerId, i32, Directed>;
+type PeerIdToNodexIdxMap = DashMap<PeerId, NodeIndex>;
+type NextHopMap = DashMap<PeerId, (PeerId, i32)>;
+
 // computed with SyncedRouteInfo. used to get next hop.
 #[derive(Debug)]
 struct RouteTable {
     peer_infos: DashMap<PeerId, RoutePeerInfo>,
-    next_hop_map: DashMap<PeerId, (PeerId, i32)>,
+    next_hop_map: NextHopMap,
     ipv4_peer_id_map: DashMap<Ipv4Addr, PeerId>,
     cidr_peer_id_map: DashMap<cidr::IpCidr, PeerId>,
 }
@@ -393,7 +409,121 @@ impl RouteTable {
             .map(|x| NatType::try_from(x.udp_stun_info as i32).unwrap())
     }
 
-    fn build_from_synced_info(&self, my_peer_id: PeerId, synced_info: &SyncedRouteInfo) {
+    fn build_peer_graph_from_synced_info<T: RouteCostCalculatorInterface>(
+        peers: Vec<PeerId>,
+        synced_info: &SyncedRouteInfo,
+        cost_calc: &mut T,
+    ) -> (PeerGraph, PeerIdToNodexIdxMap) {
+        let mut graph: PeerGraph = Graph::new();
+        let peer_id_to_node_index = PeerIdToNodexIdxMap::new();
+        for peer_id in peers.iter() {
+            peer_id_to_node_index.insert(*peer_id, graph.add_node(*peer_id));
+        }
+
+        for peer_id in peers.iter() {
+            let connected_peers = synced_info
+                .get_connected_peers(*peer_id)
+                .unwrap_or(BTreeSet::new());
+            for dst_peer_id in connected_peers.iter() {
+                let Some(dst_idx) = peer_id_to_node_index.get(dst_peer_id) else {
+                    continue;
+                };
+
+                graph.add_edge(
+                    *peer_id_to_node_index.get(&peer_id).unwrap(),
+                    *dst_idx,
+                    cost_calc.calculate_cost(*peer_id, *dst_peer_id),
+                );
+            }
+        }
+
+        (graph, peer_id_to_node_index)
+    }
+
+    fn gen_next_hop_map_with_least_hop<T: RouteCostCalculatorInterface>(
+        my_peer_id: PeerId,
+        graph: &PeerGraph,
+        idx_map: &PeerIdToNodexIdxMap,
+        cost_calc: &mut T,
+    ) -> NextHopMap {
+        let res = dijkstra(&graph, *idx_map.get(&my_peer_id).unwrap(), None, |_| 1);
+        let next_hop_map = NextHopMap::new();
+        for (node_idx, cost) in res.iter() {
+            if *cost == 0 {
+                continue;
+            }
+            let all_paths = all_simple_paths::<Vec<_>, _>(
+                graph,
+                *idx_map.get(&my_peer_id).unwrap(),
+                *node_idx,
+                *cost - 1,
+                Some(*cost - 1),
+            )
+            .collect::<Vec<_>>();
+
+            assert!(!all_paths.is_empty());
+
+            // find a path with least cost.
+            let mut min_cost = i32::MAX;
+            let mut min_path = Vec::new();
+            for path in all_paths.iter() {
+                let mut cost = 0;
+                for i in 0..path.len() - 1 {
+                    let src_peer_id = *graph.node_weight(path[i]).unwrap();
+                    let dst_peer_id = *graph.node_weight(path[i + 1]).unwrap();
+                    cost += cost_calc.calculate_cost(src_peer_id, dst_peer_id);
+                }
+
+                if cost <= min_cost {
+                    min_cost = cost;
+                    min_path = path.clone();
+                }
+            }
+            next_hop_map.insert(
+                *graph.node_weight(*node_idx).unwrap(),
+                (*graph.node_weight(min_path[1]).unwrap(), *cost as i32),
+            );
+        }
+
+        next_hop_map
+    }
+
+    fn gen_next_hop_map_with_least_cost(
+        my_peer_id: PeerId,
+        graph: &PeerGraph,
+        idx_map: &PeerIdToNodexIdxMap,
+    ) -> NextHopMap {
+        let next_hop_map = NextHopMap::new();
+        for item in idx_map.iter() {
+            if *item.key() == my_peer_id {
+                continue;
+            }
+
+            let dst_peer_node_idx = *item.value();
+
+            let Some((cost, path)) = astar::astar(
+                graph,
+                *idx_map.get(&my_peer_id).unwrap(),
+                |node_idx| node_idx == dst_peer_node_idx,
+                |e| *e.weight(),
+                |_| 0,
+            ) else {
+                continue;
+            };
+
+            next_hop_map.insert(*item.key(), (*graph.node_weight(path[1]).unwrap(), cost));
+        }
+
+        next_hop_map
+    }
+
+    fn build_from_synced_info<T: RouteCostCalculatorInterface>(
+        &self,
+        my_peer_id: PeerId,
+        synced_info: &SyncedRouteInfo,
+        policy: NextHopPolicy,
+        mut cost_calc: T,
+    ) {
         // build  peer_infos
         self.peer_infos.clear();
         for item in synced_info.peer_infos.iter() {
@@ -410,28 +540,20 @@ impl RouteTable {
         // build next hop map
         self.next_hop_map.clear();
         self.next_hop_map.insert(my_peer_id, (my_peer_id, 0));
-        for item in self.peer_infos.iter() {
-            let peer_id = *item.key();
-            if peer_id == my_peer_id {
-                continue;
-            }
-            let Some(path) = pathfinding::prelude::bfs(
-                &my_peer_id,
-                |p| {
-                    synced_info
-                        .get_connected_peers(*p)
-                        .unwrap_or_else(|| BTreeSet::new())
-                },
-                |x| *x == peer_id,
-            ) else {
-                continue;
-            };
-            if !path.is_empty() {
-                assert!(path.len() >= 2);
-                self.next_hop_map
-                    .insert(peer_id, (path[1], (path.len() - 1) as i32));
-            }
+        let (graph, idx_map) = Self::build_peer_graph_from_synced_info(
+            self.peer_infos.iter().map(|x| *x.key()).collect(),
+            &synced_info,
+            &mut cost_calc,
+        );
+        let next_hop_map = if matches!(policy, NextHopPolicy::LeastHop) {
+            Self::gen_next_hop_map_with_least_hop(my_peer_id, &graph, &idx_map, &mut cost_calc)
+        } else {
+            Self::gen_next_hop_map_with_least_cost(my_peer_id, &graph, &idx_map)
+        };
+        for item in next_hop_map.iter() {
+            self.next_hop_map.insert(*item.key(), *item.value());
         }
+        // build graph
 
         // build ipv4_peer_id_map, cidr_peer_id_map
         self.ipv4_peer_id_map.clear();
@@ -563,7 +685,9 @@ struct PeerRouteServiceImpl {
 
     interface: Arc<Mutex<Option<RouteInterfaceBox>>>,
 
+    cost_calculator: Arc<std::sync::Mutex<Option<RouteCostCalculator>>>,
     route_table: RouteTable,
+    route_table_with_cost: RouteTable,
     synced_route_info: Arc<SyncedRouteInfo>,
     cached_local_conn_map: std::sync::Mutex<RouteConnBitmap>,
 }
@@ -585,9 +709,17 @@ impl PeerRouteServiceImpl {
         PeerRouteServiceImpl {
             my_peer_id,
             global_ctx,
-            interface: Arc::new(Mutex::new(None)),
             sessions: DashMap::new(),
+
+            interface: Arc::new(Mutex::new(None)),
+
+            cost_calculator: Arc::new(std::sync::Mutex::new(Some(Box::new(
+                DefaultRouteCostCalculator,
+            )))),
+
             route_table: RouteTable::new(),
+            route_table_with_cost: RouteTable::new(),
+
             synced_route_info: Arc::new(SyncedRouteInfo {
                 peer_infos: DashMap::new(),
                 conn_map: DashMap::new(),
@@ -649,8 +781,32 @@ impl PeerRouteServiceImpl {
     }
 
     fn update_route_table(&self) {
-        self.route_table
-            .build_from_synced_info(self.my_peer_id, &self.synced_route_info);
+        let mut calc_locked = self.cost_calculator.lock().unwrap();
+
+        calc_locked.as_mut().unwrap().begin_update();
+        self.route_table.build_from_synced_info(
+            self.my_peer_id,
+            &self.synced_route_info,
+            NextHopPolicy::LeastHop,
+            calc_locked.as_mut().unwrap(),
+        );
+
+        self.route_table_with_cost.build_from_synced_info(
+            self.my_peer_id,
+            &self.synced_route_info,
+            NextHopPolicy::LeastCost,
+            calc_locked.as_mut().unwrap(),
+        );
+        calc_locked.as_mut().unwrap().end_update();
+    }
+
+    fn cost_calculator_need_update(&self) -> bool {
+        self.cost_calculator
+            .lock()
+            .unwrap()
+            .as_ref()
+            .map(|x| x.need_update())
+            .unwrap_or(false)
     }
 
     fn update_route_table_and_cached_local_conn_bitmap(&self) {
@@ -1173,6 +1329,7 @@ impl PeerRoute {
         session_mgr.maintain_sessions(service_impl).await;
     }
 
+    #[tracing::instrument(skip(session_mgr))]
     async fn update_my_peer_info_routine(
         service_impl: Arc<PeerRouteServiceImpl>,
         session_mgr: RouteSessionManager,
@@ -1183,6 +1340,11 @@ impl PeerRoute {
                 session_mgr.sync_now("update_my_infos");
             }
 
+            if service_impl.cost_calculator_need_update() {
+                tracing::debug!("cost_calculator_need_update");
+                service_impl.update_route_table();
+            }
+
             select! {
                 ev = global_event_receiver.recv() => {
                     tracing::info!(?ev, "global event received in update_my_peer_info_routine");
@@ -1234,6 +1396,19 @@ impl Route for PeerRoute {
         route_table.get_next_hop(dst_peer_id).map(|x| x.0)
     }
 
+    async fn get_next_hop_with_policy(
+        &self,
+        dst_peer_id: PeerId,
+        policy: NextHopPolicy,
+    ) -> Option<PeerId> {
+        let route_table = if matches!(policy, NextHopPolicy::LeastCost) {
+            &self.service_impl.route_table_with_cost
+        } else {
+            &self.service_impl.route_table
+        };
+        route_table.get_next_hop(dst_peer_id).map(|x| x.0)
+    }
+
     async fn list_routes(&self) -> Vec<crate::rpc::Route> {
         let route_table = &self.service_impl.route_table;
         let mut routes = Vec::new();
@@ -1265,6 +1440,11 @@ impl Route for PeerRoute {
         tracing::info!(?ipv4_addr, "no peer id for ipv4");
         None
     }
+
+    async fn set_route_cost_fn(&self, _cost_fn: RouteCostCalculator) {
+        *self.service_impl.cost_calculator.lock().unwrap() = Some(_cost_fn);
+        self.service_impl.update_route_table();
+    }
 }
 
 impl PeerPacketFilter for Arc<PeerRoute> {}
@@ -1282,7 +1462,7 @@ mod tests {
         connector::udp_hole_punch::tests::replace_stun_info_collector,
         peers::{
             peer_manager::{PeerManager, RouteAlgoType},
-            route_trait::Route,
+            route_trait::{NextHopPolicy, Route, RouteCostCalculatorInterface},
             tests::{connect_peer_manager, wait_for_condition},
         },
         rpc::NatType,
@@ -1609,4 +1789,91 @@ mod tests {
         println!("session: {:?}", r_a.session_mgr.dump_sessions());
         check_rpc_counter(&r_a, p_b.my_peer_id(), 2, 2);
     }
+
+    #[tokio::test]
+    async fn test_cost_calculator() {
+        let p_a = create_mock_pmgr().await;
+        let p_b = create_mock_pmgr().await;
+        let p_c = create_mock_pmgr().await;
+        let p_d = create_mock_pmgr().await;
+        connect_peer_manager(p_a.clone(), p_b.clone()).await;
+        connect_peer_manager(p_a.clone(), p_c.clone()).await;
+        connect_peer_manager(p_d.clone(), p_b.clone()).await;
+        connect_peer_manager(p_d.clone(), p_c.clone()).await;
+        connect_peer_manager(p_b.clone(), p_c.clone()).await;
+
+        let _r_a = create_mock_route(p_a.clone()).await;
+        let _r_b = create_mock_route(p_b.clone()).await;
+        let _r_c = create_mock_route(p_c.clone()).await;
+        let r_d = create_mock_route(p_d.clone()).await;
+
+        // in normal mode, packet from p_c should directly forward to p_a
+        wait_for_condition(
+            || async { r_d.get_next_hop(p_a.my_peer_id()).await != None },
+            Duration::from_secs(5),
+        )
+        .await;
+
+        struct TestCostCalculator {
+            p_a_peer_id: PeerId,
+            p_b_peer_id: PeerId,
+            p_c_peer_id: PeerId,
+            p_d_peer_id: PeerId,
+        }
+
+        impl RouteCostCalculatorInterface for TestCostCalculator {
+            fn calculate_cost(&self, src: PeerId, dst: PeerId) -> i32 {
+                if src == self.p_d_peer_id && dst == self.p_b_peer_id {
+                    return 100;
+                }
+
+                if src == self.p_d_peer_id && dst == self.p_c_peer_id {
+                    return 1;
+                }
+
+                if src == self.p_c_peer_id && dst == self.p_a_peer_id {
+                    return 101;
+                }
+
+                if src == self.p_b_peer_id && dst == self.p_a_peer_id {
+                    return 1;
+                }
+
+                if src == self.p_c_peer_id && dst == self.p_b_peer_id {
+                    return 2;
+                }
+
+                1
+            }
+        }
+
+        r_d.set_route_cost_fn(Box::new(TestCostCalculator {
+            p_a_peer_id: p_a.my_peer_id(),
+            p_b_peer_id: p_b.my_peer_id(),
+            p_c_peer_id: p_c.my_peer_id(),
+            p_d_peer_id: p_d.my_peer_id(),
+        }))
+        .await;
+
+        // after set cost, packet from p_c should forward to p_b first
+        wait_for_condition(
+            || async {
+                r_d.get_next_hop_with_policy(p_a.my_peer_id(), NextHopPolicy::LeastCost)
+                    .await
+                    == Some(p_c.my_peer_id())
+            },
+            Duration::from_secs(5),
+        )
+        .await;
+
+        wait_for_condition(
+            || async {
+                r_d.get_next_hop_with_policy(p_a.my_peer_id(), NextHopPolicy::LeastHop)
+                    .await
+                    == Some(p_b.my_peer_id())
+            },
+            Duration::from_secs(5),
+        )
+        .await;
+    }
 }
diff --git a/easytier/src/peers/route_trait.rs b/easytier/src/peers/route_trait.rs
index 66364355..ad64df32 100644
--- a/easytier/src/peers/route_trait.rs
+++ b/easytier/src/peers/route_trait.rs
@@ -5,6 +5,18 @@ use tokio_util::bytes::Bytes;
 
 use crate::common::{error::Error, PeerId};
 
+#[derive(Clone, Debug)]
+pub enum NextHopPolicy {
+    LeastHop,
+    LeastCost,
+}
+
+impl Default for NextHopPolicy {
+    fn default() -> Self {
+        NextHopPolicy::LeastHop
+    }
+}
+
 #[async_trait]
 pub trait RouteInterface {
     async fn list_peers(&self) -> Vec<PeerId>;
@@ -19,6 +31,31 @@ pub trait RouteInterface {
 
 pub type RouteInterfaceBox = Box<dyn RouteInterface + Send + Sync>;
 
+#[auto_impl::auto_impl(Box , &mut)]
+pub trait RouteCostCalculatorInterface: Send + Sync {
+    fn begin_update(&mut self) {}
+    fn end_update(&mut self) {}
+
+    fn calculate_cost(&self, _src: PeerId, _dst: PeerId) -> i32 {
+        1
+    }
+
+    fn need_update(&self) -> bool {
+        false
+    }
+
+    fn dump(&self) -> String {
+        "All routes have cost 1".to_string()
+    }
+}
+
+#[derive(Clone, Debug, Default)]
+pub struct DefaultRouteCostCalculator;
+
+impl RouteCostCalculatorInterface for DefaultRouteCostCalculator {}
+
+pub type RouteCostCalculator = Box<dyn RouteCostCalculatorInterface>;
+
 #[async_trait]
 #[auto_impl::auto_impl(Box, Arc)]
 pub trait Route {
@@ -26,11 +63,21 @@ pub trait Route {
     async fn close(&self);
 
     async fn get_next_hop(&self, peer_id: PeerId) -> Option<PeerId>;
+    async fn get_next_hop_with_policy(
+        &self,
+        peer_id: PeerId,
+        _policy: NextHopPolicy,
+    ) -> Option<PeerId> {
+        self.get_next_hop(peer_id).await
+    }
+
     async fn list_routes(&self) -> Vec<crate::rpc::Route>;
 
     async fn get_peer_id_by_ipv4(&self, _ipv4: &Ipv4Addr) -> Option<PeerId> {
         None
     }
+
+    async fn set_route_cost_fn(&self, _cost_fn: RouteCostCalculator) {}
 }
 
 pub type ArcRoute = Arc<Box<dyn Route + Send + Sync>>;
diff --git a/easytier/src/tests/three_node.rs b/easytier/src/tests/three_node.rs
index 1ecdee33..279b166a 100644
--- a/easytier/src/tests/three_node.rs
+++ b/easytier/src/tests/three_node.rs
@@ -187,12 +187,13 @@ pub async fn basic_three_node_test(#[values("tcp", "udp", "wg", "ws", "wss")] pr
 pub async fn tcp_proxy_three_node_test(#[values("tcp", "udp", "wg")] proto: &str) {
     use crate::tunnel::{common::tests::_tunnel_pingpong_netns, tcp::TcpTunnelListener};
 
-    let insts = init_three_node(proto).await;
+    let mut insts = init_three_node(proto).await;
 
     insts[2]
         .get_global_ctx()
         .add_proxy_cidr("10.1.2.0/24".parse().unwrap())
         .unwrap();
+    insts[2].run_ip_proxy().await.unwrap();
     assert_eq!(insts[2].get_global_ctx().get_proxy_cidrs().len(), 1);
 
     wait_proxy_route_appear(
@@ -222,12 +223,13 @@ pub async fn tcp_proxy_three_node_test(#[values("tcp", "udp", "wg")] proto: &str
 #[tokio::test]
 #[serial_test::serial]
 pub async fn icmp_proxy_three_node_test(#[values("tcp", "udp", "wg")] proto: &str) {
-    let insts = init_three_node(proto).await;
+    let mut insts = init_three_node(proto).await;
 
     insts[2]
         .get_global_ctx()
         .add_proxy_cidr("10.1.2.0/24".parse().unwrap())
         .unwrap();
+    insts[2].run_ip_proxy().await.unwrap();
     assert_eq!(insts[2].get_global_ctx().get_proxy_cidrs().len(), 1);
 
     wait_proxy_route_appear(
@@ -318,12 +320,13 @@ pub async fn proxy_three_node_disconnect_test(#[values("tcp", "wg")] proto: &str
 pub async fn udp_proxy_three_node_test(#[values("tcp", "udp", "wg")] proto: &str) {
     use crate::tunnel::{common::tests::_tunnel_pingpong_netns, udp::UdpTunnelListener};
 
-    let insts = init_three_node(proto).await;
+    let mut insts = init_three_node(proto).await;
 
     insts[2]
         .get_global_ctx()
         .add_proxy_cidr("10.1.2.0/24".parse().unwrap())
         .unwrap();
+    insts[2].run_ip_proxy().await.unwrap();
     assert_eq!(insts[2].get_global_ctx().get_proxy_cidrs().len(), 1);
 
     wait_proxy_route_appear(
diff --git a/easytier/src/tunnel/packet_def.rs b/easytier/src/tunnel/packet_def.rs
index 036b40d8..567bfa65 100644
--- a/easytier/src/tunnel/packet_def.rs
+++ b/easytier/src/tunnel/packet_def.rs
@@ -59,6 +59,7 @@ pub enum PacketType {
 bitflags::bitflags! {
     struct PeerManagerHeaderFlags: u8 {
         const ENCRYPTED = 0b0000_0001;
+        const LATENCY_FIRST = 0b0000_0010;
     }
 }
 
@@ -69,7 +70,8 @@ pub struct PeerManagerHeader {
     pub to_peer_id: U32<DefaultEndian>,
     pub packet_type: u8,
     pub flags: u8,
-    reserved: U16<DefaultEndian>,
+    pub forward_counter: u8,
+    reserved: u8,
     pub len: U32<DefaultEndian>,
 }
 pub const PEER_MANAGER_HEADER_SIZE: usize = std::mem::size_of::<PeerManagerHeader>();
@@ -90,6 +92,22 @@ impl PeerManagerHeader {
         }
         self.flags = flags.bits();
     }
+
+    pub fn is_latency_first(&self) -> bool {
+        PeerManagerHeaderFlags::from_bits(self.flags)
+            .unwrap()
+            .contains(PeerManagerHeaderFlags::LATENCY_FIRST)
+    }
+
+    pub fn set_latency_first(&mut self, latency_first: bool) {
+        let mut flags = PeerManagerHeaderFlags::from_bits(self.flags).unwrap();
+        if latency_first {
+            flags.insert(PeerManagerHeaderFlags::LATENCY_FIRST);
+        } else {
+            flags.remove(PeerManagerHeaderFlags::LATENCY_FIRST);
+        }
+        self.flags = flags.bits();
+    }
 }
 
 // reserve the space for aes tag and nonce
@@ -362,6 +380,7 @@ impl ZCPacket {
         hdr.to_peer_id.set(to_peer_id);
         hdr.packet_type = packet_type;
         hdr.flags = 0;
+        hdr.forward_counter = 1;
         hdr.len.set(payload_len as u32);
     }