diff --git a/backend/src/MoShiro.Backend.Analysis/Metrics/MetricRegistry.cs b/backend/src/MoShiro.Backend.Analysis/Metrics/MetricRegistry.cs
index 79dbd57..a0d3066 100644
--- a/backend/src/MoShiro.Backend.Analysis/Metrics/MetricRegistry.cs
+++ b/backend/src/MoShiro.Backend.Analysis/Metrics/MetricRegistry.cs
@@ -12,7 +12,7 @@ public static class MetricRegistry
     [
         LinkMetrics.Rtt, LinkMetrics.LossUp, LinkMetrics.LossDown, LinkMetrics.LossTotal,
         LinkMetrics.JitterUp, LinkMetrics.JitterDown, LinkMetrics.LossRun, LinkMetrics.LossRunUp, LinkMetrics.LossRunDown, LinkMetrics.Reorder, LinkMetrics.Dup, LinkMetrics.SamplesUdp,
-        TcpMetrics.Rtt, TcpMetrics.Slow, TcpMetrics.Stall, TcpMetrics.StallMax, TcpMetrics.Retrans, TcpMetrics.Srtt, TcpMetrics.BulkRate, TcpMetrics.BulkPeak, TcpMetrics.SamplesTcp,
+        TcpMetrics.Rtt, TcpMetrics.Slow, TcpMetrics.Stall, TcpMetrics.StallMax, TcpMetrics.Retrans, TcpMetrics.RetransUp, TcpMetrics.RetransDown, TcpMetrics.Srtt, TcpMetrics.BulkRate, TcpMetrics.BulkPeak, TcpMetrics.SamplesTcp,
         SessionMetrics.ConnectSuccess, SessionMetrics.ConnectTcp, SessionMetrics.ConnectTls,
         SessionMetrics.FailTimeout, SessionMetrics.FailReset, SessionMetrics.FailTls,
         SessionMetrics.HoldResets, SessionMetrics.HoldLifetime,
@@ -24,7 +24,7 @@ public static class MetricRegistry
     [
         new("quic", "QUIC Datagram", ["loss.up", "loss.down", "loss.total", "rtt.p50", "rtt.p95", "rtt.p99", "jitter.up.p95", "jitter.down.p95", "loss.run.up_max", "loss.run.down_max", "reorder", "dup"]),
         new("udp", "QUIC Datagram (legacy alias)", ["loss.up", "loss.down", "loss.total", "rtt.p50", "rtt.p95", "rtt.p99", "jitter.up.p95", "jitter.down.p95", "loss.run_max", "reorder", "dup"]),
-        new("tcp", "TCP", ["tcp.rtt.p50", "tcp.rtt.p95", "tcp.rtt.p99", "tcp.rtt.p999", "tcp.rtt.max", "tcp.rtt.tail", "tcp.slow", "tcp.stall.per_min", "tcp.stall_max", "tcp.retrans", "tcp.srtt.p95"]),
+        new("tcp", "TCP", ["tcp.rtt.p50", "tcp.rtt.p95", "tcp.rtt.p99", "tcp.rtt.p999", "tcp.rtt.max", "tcp.rtt.tail", "tcp.slow", "tcp.stall.per_min", "tcp.stall_max", "tcp.retrans", "tcp.retrans.up", "tcp.retrans.down", "tcp.srtt.p95"]),
         new("connect", "Connect", ["connect.success", "connect.tcp_ms.p95", "connect.tls_ms.p95", "connect.fail.timeout", "connect.fail.rst", "connect.fail.tls"]),
         new("session", "Session", ["hold.resets.per_h", "hold.lifetime_max"]),
         new("scores", "Scores", ["score.base", "score.mc", "score.hy2", "score.reality"]),
diff --git a/backend/src/MoShiro.Backend.Analysis/Metrics/TcpMetrics.cs b/backend/src/MoShiro.Backend.Analysis/Metrics/TcpMetrics.cs
index a4759f1..1c27c3c 100644
--- a/backend/src/MoShiro.Backend.Analysis/Metrics/TcpMetrics.cs
+++ b/backend/src/MoShiro.Backend.Analysis/Metrics/TcpMetrics.cs
@@ -27,6 +27,14 @@ public static class TcpMetrics
     public static readonly MetricDef Retrans = Metric.Ratio(
         "tcp.retrans", s_tcpInfo, Ops.KernelDelta("retrans_total", "segs_out"), "TCP retransmissions", "Retransmitted segments as a share of segments sent (kernel counters).", good: 0.5, poor: 3);
 
+    public static readonly MetricDef RetransUp = Metric.Ratio(
+        "tcp.retrans.up", s_tcpInfo, Ops.KernelDelta("retrans_total", "segs_out", TcpSide.Forward), "TCP retransmissions (forward)",
+        "Retransmitted segments as a share of segments sent by the 拨号方 (kernel counters): loss on the 拨号方 to Agent path.", good: 0.5, poor: 3);
+
+    public static readonly MetricDef RetransDown = Metric.Ratio(
+        "tcp.retrans.down", s_tcpInfo, Ops.KernelDelta("retrans_total", "segs_out", TcpSide.Return), "TCP retransmissions (return)",
+        "Retransmitted segments as a share of segments sent by the Agent (kernel counters): loss on the Agent to 拨号方 path.", good: 0.5, poor: 3);
+
     public static readonly MetricDef Srtt = Metric.Histogram(
         "tcp.srtt", s_tcpInfo, Ops.Column("srtt_us", 0.001), "Kernel srtt", "Smoothed RTT sampled from the kernel.", Unit.Ms, [Stat.P95], good: 60, poor: 200);
 
diff --git a/backend/src/MoShiro.Backend.Analysis/Ops/Ops.cs b/backend/src/MoShiro.Backend.Analysis/Ops/Ops.cs
index 0755942..0713448 100644
--- a/backend/src/MoShiro.Backend.Analysis/Ops/Ops.cs
+++ b/backend/src/MoShiro.Backend.Analysis/Ops/Ops.cs
@@ -23,7 +23,7 @@ public static class Ops
 
     public static MetricOp RowCount { get; } = new RowCountOp();
 
-    public static MetricOp KernelDelta(string field, string over) => new KernelDeltaOp(field, over);
+    public static MetricOp KernelDelta(string field, string over, TcpSide only = TcpSide.Both) => new KernelDeltaOp(field, over, only);
 
     public static MetricOp Column(string column, double scale) => new ColumnValueOp(column, scale);
 
diff --git a/backend/src/MoShiro.Backend.Analysis/Ops/SessionOps.cs b/backend/src/MoShiro.Backend.Analysis/Ops/SessionOps.cs
index 2479342..77c379b 100644
--- a/backend/src/MoShiro.Backend.Analysis/Ops/SessionOps.cs
+++ b/backend/src/MoShiro.Backend.Analysis/Ops/SessionOps.cs
@@ -9,19 +9,32 @@ internal static class TcpInfoTime
         side is not null && side.Values[row] == 0 ? view.DialerToUtcMs(ts.Values[row]) : view.AgentToUtcMs(ts.Values[row]);
 }
 
-/// <summary>两次采样之间累计计数的差值（分子）与另一个累计计数的差值（分母），按 (side, conn) 分别计算；旧数据没有 conn 时按 side 计算。</summary>
+/// <summary>哪一侧的内核采样：拨号方 一侧发出的段走去程（拨号方到 Agent），Agent 一侧发出的段走回程。</summary>
+public enum TcpSide
+{
+    Both,
+    Forward,
+    Return,
+}
+
+/// <summary>
+/// 两次采样之间累计计数的差值（分子）与另一个累计计数的差值（分母），按 (side, conn) 分别计算；旧数据没有 conn 时按 side 计算。
+/// 只取一侧时，另一侧的行整个跳过（基线也不记），所以去程和回程的重传各自只由自己这一侧发出的段算出。
+/// </summary>
 internal sealed class KernelDeltaOp : MetricOp
 {
     private readonly string _field;
     private readonly string _over;
+    private readonly TcpSide _only;
 
-    public KernelDeltaOp(string field, string over)
+    public KernelDeltaOp(string field, string over, TcpSide only = TcpSide.Both)
     {
         _field = field;
         _over = over;
+        _only = only;
     }
 
-    public override string Signature => $"kernel_delta/{_field}/{_over}/2";
+    public override string Signature => _only == TcpSide.Both ? $"kernel_delta/{_field}/{_over}/2" : $"kernel_delta/{_field}/{_over}/{_only}/2";
 
     public override void Evaluate(ChunkView view, RawStream stream, IObservationSink sink)
     {
@@ -43,7 +56,13 @@ internal sealed class KernelDeltaOp : MetricOp
                 continue;
             }
 
-            var key = (side?.Values[i] ?? 0, connection?.IsValid(i) == true ? connection.Values[i] : 0);
+            long rowSide = side?.Values[i] ?? 0;
+            if ((_only == TcpSide.Forward && rowSide != 0) || (_only == TcpSide.Return && rowSide == 0))
+            {
+                continue;
+            }
+
+            var key = (rowSide, connection?.IsValid(i) == true ? connection.Values[i] : 0);
             if (last.TryGetValue(key, out (long Ts, long Field, long Over) previous))
             {
                 // Ignore delayed/duplicate samples without replacing the newer baseline.
diff --git a/backend/tests/MoShiro.Backend.Analysis.Tests/OpTests.cs b/backend/tests/MoShiro.Backend.Analysis.Tests/OpTests.cs
index 949c0fb..9da06ce 100644
--- a/backend/tests/MoShiro.Backend.Analysis.Tests/OpTests.cs
+++ b/backend/tests/MoShiro.Backend.Analysis.Tests/OpTests.cs
@@ -260,6 +260,23 @@ public sealed class OpTests
         Assert.Equal(300UL, retrans.Denominator);
     }
 
+    [Fact]
+    public void Retrans_ForwardAndReturnAreSplitBySide()
+    {
+        long ts = ChunkFactory.DialerUs(0);
+        var builder = new StreamBuilder(Kinds.TcpEcho.FindStream("tcp_info")!);
+        builder.Add(ts, 0, 40_000, 0, 10, 10, 1000, 0, 1);
+        builder.Add(ts, 1, 40_000, 0, 10, 100, 2000, 0, 1);
+        builder.Add(ts + 1_000_000, 0, 40_000, 0, 10, 11, 1100, 0, 1);
+        builder.Add(ts + 1_000_000, 1, 40_000, 0, 10, 102, 2200, 0, 1);
+        RawChunk chunk = ChunkFactory.Echo(s_agent, "tcp_echo", T0, 10, 100,
+            _ => new EchoPacket(false, false, 20_000, 20_000), extraStreams: [builder.Build()]);
+        var forward = (RatioAcc)EvaluateOneBucket(chunk, "tcp.retrans.up").Items["tcp.retrans.up"];
+        var back = (RatioAcc)EvaluateOneBucket(chunk, "tcp.retrans.down").Items["tcp.retrans.down"];
+        Assert.Equal((1UL, 100UL), (forward.Numerator, forward.Denominator));
+        Assert.Equal((2UL, 200UL), (back.Numerator, back.Denominator));
+    }
+
     [Fact]
     public void Connect_Outcomes_AreCountedByClass()
     {
diff --git a/web/display/src/LineStrips.tsx b/web/display/src/LineStrips.tsx
index c14aac2..5fecb08 100644
--- a/web/display/src/LineStrips.tsx
+++ b/web/display/src/LineStrips.tsx
@@ -29,11 +29,11 @@ interface Props {
   m: Record<string, number | null | undefined>
 }
 
-/** 一条线路的 QUIC/TCP 双行摘要，各自显示时延、质量点阵和丢包/重传率。 */
+/** 一条线路的 QUIC/TCP 摘要：RTT 是往返（⇄）；去程是拨号方到监听方（→），回程反过来（←）；QUIC 看各方向丢包，TCP 看各方向重传，都配质量点阵。 */
 export function LineStrips({ lineId, range, m }: Props) {
   const info = OVERVIEW_RANGES.find((r) => r.value === range) ?? OVERVIEW_RANGES[0]
   const series = useQuery(
-    () => api.get<SeriesDto>(`/api/public/lines/${encodeURIComponent(lineId)}/series`, { range: info.value, anchor: 'now', step: info.step, preset: 'quic,tcp', metrics: 'loss.up,loss.down,loss.total,rtt.p50,rtt.p95,rtt.p99,tcp.retrans,tcp.rtt.p50' }),
+    () => api.get<SeriesDto>(`/api/public/lines/${encodeURIComponent(lineId)}/series`, { range: info.value, anchor: 'now', step: info.step, preset: 'quic,tcp', metrics: 'loss.up,loss.down,loss.total,rtt.p50,rtt.p95,rtt.p99,tcp.retrans.up,tcp.retrans.down,tcp.rtt.p50' }),
     [lineId, info.value],
     30_000,
   )
@@ -57,24 +57,25 @@ export function LineStrips({ lineId, range, m }: Props) {
   const at = shown !== null && t[shown] !== undefined ? shown : null
   const lossUp = col('loss.up')
   const lossDown = col('loss.down')
-  const retrans = col('tcp.retrans')
+  const retransUp = col('tcp.retrans.up')
+  const retransDown = col('tcp.retrans.down')
   const up = m['loss.up']
   const down = m['loss.down']
   const upText = up === null || up === undefined ? '丢包 —' : `${fmtPct(up)} 丢包`
   const downText = down === null || down === undefined ? '丢包 —' : `${fmtPct(down)} 丢包`
-  const retransValue = m['tcp.retrans']
-  const retransTone = levelOf(retransValue)
-  const retransText = retransValue === null || retransValue === undefined ? '重传 —' : `${fmtPct(retransValue)} 重传`
+  const retransUpValue = m['tcp.retrans.up']
+  const retransDownValue = m['tcp.retrans.down']
+  const retransText = (v: number | null | undefined) => (v === null || v === undefined ? '重传 —' : `${fmtPct(v)} 重传`)
   return (
     <div className="strips" ref={box} onMouseMove={onMove} onMouseLeave={() => setHover(null)}>
       <div className="line-mini-stack">
         <div className="line-mini-quic-head" title={`QUIC RTT p50 ${fmtMs(m['rtt.p50'])} · p95 ${fmtMs(m['rtt.p95'])} · p99 ${fmtMs(m['rtt.p99'])}`}>
-          <span>QUIC</span><strong className="num">{fmtMs(m['rtt.p50'])}</strong><small>悬停看 p95 / p99</small>
+          <span>QUIC RTT ⇄</span><strong className="num">{fmtMs(m['rtt.p50'])}</strong><small>悬停看 p95 / p99</small>
           {series.error ? <span className="line-mini-badge bad" title={`上一次取数失败：${series.error.message}`}>数据未更新</span> : null}
         </div>
         <div className="line-mini-direction">
           <div className="line-mini-direction-head" title={`去程 拨号方 → 监听方 丢包 ${fmtPct(up)}`}>
-            <span>去程</span>
+            <span>去程 →</span>
             <span className={`line-mini-badge ${levelOf(up)}`}>{upText}</span>
           </div>
           <div className="bars" role="img" aria-label={`近 ${common.hoursText}每 ${common.stepText}的去程丢包`}>
@@ -85,7 +86,7 @@ export function LineStrips({ lineId, range, m }: Props) {
         </div>
         <div className="line-mini-direction">
           <div className="line-mini-direction-head" title={`回程 监听方 → 拨号方 丢包 ${fmtPct(down)}`}>
-            <span>回程</span>
+            <span>回程 ←</span>
             <span className={`line-mini-badge ${levelOf(down)}`}>{downText}</span>
           </div>
           <div className="bars" role="img" aria-label={`近 ${common.hoursText}每 ${common.stepText}的回程丢包`}>
@@ -96,12 +97,28 @@ export function LineStrips({ lineId, range, m }: Props) {
         </div>
         <div className="line-mini-tcp">
           <div className="line-mini-tcp-head" title={`TCP RTT p50 ${fmtMs(m['tcp.rtt.p50'])}`}>
-            <span>TCP</span><strong className="num">{fmtMs(m['tcp.rtt.p50'])}</strong>
-            <span className={`line-mini-badge ${retransTone}`}>{retransText}</span>
+            <span>TCP RTT ⇄</span><strong className="num">{fmtMs(m['tcp.rtt.p50'])}</strong>
           </div>
-          <div className="bars" role="img" aria-label={`近 ${common.hoursText}每 ${common.stepText}的 TCP 重传`}>
-            {(s ? retrans : Array.from({ length: common.cells }, () => null)).map((value, i) => (
-              <span key={`retrans-${t[i] ?? i}`} className={`bar ${s ? levelOf(value) : 'none'}${hover === i ? ' on' : ''}`} />
+        </div>
+        <div className="line-mini-direction">
+          <div className="line-mini-direction-head" title={`TCP 去程 拨号方 → 监听方 重传 ${fmtPct(retransUpValue)}`}>
+            <span>去程 →</span>
+            <span className={`line-mini-badge ${levelOf(retransUpValue)}`}>{retransText(retransUpValue)}</span>
+          </div>
+          <div className="bars" role="img" aria-label={`近 ${common.hoursText}每 ${common.stepText}的 TCP 去程重传`}>
+            {(s ? retransUp : Array.from({ length: common.cells }, () => null)).map((value, i) => (
+              <span key={`retrans-up-${t[i] ?? i}`} className={`bar ${s ? levelOf(value) : 'none'}${hover === i ? ' on' : ''}`} />
+            ))}
+          </div>
+        </div>
+        <div className="line-mini-direction">
+          <div className="line-mini-direction-head" title={`TCP 回程 监听方 → 拨号方 重传 ${fmtPct(retransDownValue)}`}>
+            <span>回程 ←</span>
+            <span className={`line-mini-badge ${levelOf(retransDownValue)}`}>{retransText(retransDownValue)}</span>
+          </div>
+          <div className="bars" role="img" aria-label={`近 ${common.hoursText}每 ${common.stepText}的 TCP 回程重传`}>
+            {(s ? retransDown : Array.from({ length: common.cells }, () => null)).map((value, i) => (
+              <span key={`retrans-down-${t[i] ?? i}`} className={`bar ${s ? levelOf(value) : 'none'}${hover === i ? ' on' : ''}`} />
             ))}
           </div>
         </div>
@@ -127,7 +144,10 @@ export function LineStrips({ lineId, range, m }: Props) {
             <div className="pop-group">
               <span className="pop-name">TCP</span>
               <span>
-                重传 <em className={levelOf(col('tcp.retrans')[at])}>{fmtPct(col('tcp.retrans')[at])}</em>
+                去程重传 <em className={levelOf(col('tcp.retrans.up')[at])}>{fmtPct(col('tcp.retrans.up')[at])}</em>
+              </span>
+              <span>
+                回程重传 <em className={levelOf(col('tcp.retrans.down')[at])}>{fmtPct(col('tcp.retrans.down')[at])}</em>
               </span>
               <span>
                 RTT p50 <em>{fmtMs(col('tcp.rtt.p50')[at])}</em>
diff --git a/web/display/src/pages/Compare.tsx b/web/display/src/pages/Compare.tsx
index f0e66c5..1abaa6f 100644
--- a/web/display/src/pages/Compare.tsx
+++ b/web/display/src/pages/Compare.tsx
@@ -22,14 +22,16 @@ const METRICS: MetricInfo[] = [
   { id: 'rtt.p50', label: '延迟 p50', unit: 'ms', better: 'lower' },
   { id: 'rtt.p95', label: '延迟 p95', unit: 'ms', better: 'lower' },
   { id: 'loss.total', label: 'QUIC 丢包', unit: '%', better: 'lower' },
-  { id: 'loss.up', label: 'QUIC 上行丢包', unit: '%', better: 'lower' },
-  { id: 'loss.down', label: 'QUIC 下行丢包', unit: '%', better: 'lower' },
-  { id: 'loss.run.up_max', label: 'QUIC 上行最长连续丢包', unit: '', better: 'lower' },
-  { id: 'loss.run.down_max', label: 'QUIC 下行最长连续丢包', unit: '', better: 'lower' },
-  { id: 'jitter.up.p95', label: '上行抖动', unit: 'ms', better: 'lower' },
-  { id: 'jitter.down.p95', label: '下行抖动', unit: 'ms', better: 'lower' },
+  { id: 'loss.up', label: 'QUIC 去程丢包', unit: '%', better: 'lower' },
+  { id: 'loss.down', label: 'QUIC 回程丢包', unit: '%', better: 'lower' },
+  { id: 'loss.run.up_max', label: 'QUIC 去程最长连续丢包', unit: '', better: 'lower' },
+  { id: 'loss.run.down_max', label: 'QUIC 回程最长连续丢包', unit: '', better: 'lower' },
+  { id: 'jitter.up.p95', label: 'QUIC 去程抖动', unit: 'ms', better: 'lower' },
+  { id: 'jitter.down.p95', label: 'QUIC 回程抖动', unit: 'ms', better: 'lower' },
   { id: 'tcp.rtt.p50', label: 'TCP RTT p50', unit: 'ms', better: 'lower' },
   { id: 'tcp.retrans', label: 'TCP 重传', unit: '%', better: 'lower' },
+  { id: 'tcp.retrans.up', label: 'TCP 去程重传', unit: '%', better: 'lower' },
+  { id: 'tcp.retrans.down', label: 'TCP 回程重传', unit: '%', better: 'lower' },
   { id: 'score.reality', label: 'REALITY 评分', unit: '', better: 'higher' },
   { id: 'score.hy2', label: 'Hy2 评分', unit: '', better: 'higher' },
   { id: 'score.mc', label: 'MC 评分', unit: '', better: 'higher' },
diff --git a/web/display/src/pages/Line.tsx b/web/display/src/pages/Line.tsx
index e5732e5..9b0ce0c 100644
--- a/web/display/src/pages/Line.tsx
+++ b/web/display/src/pages/Line.tsx
@@ -38,7 +38,8 @@ const TILES: { group: Exclude<MetricGroup, 'score'>; label: string; key: string;
   { group: 'tcp-connect', label: 'TCP RTT p50', key: 'tcp.rtt.p50', fmt: fmtMs },
   { group: 'tcp-connect', label: 'TCP RTT p99', key: 'tcp.rtt.p99', fmt: fmtMs },
   { group: 'tcp-connect', label: 'TCP RTT 最大', key: 'tcp.rtt.max', fmt: fmtMs },
-  { group: 'tcp-connect', label: 'TCP 重传率', key: 'tcp.retrans', fmt: fmtPct, good: 0.5, poor: 3 },
+  { group: 'tcp-connect', label: 'TCP 去程重传率', key: 'tcp.retrans.up', fmt: fmtPct, good: 0.5, poor: 3 },
+  { group: 'tcp-connect', label: 'TCP 回程重传率', key: 'tcp.retrans.down', fmt: fmtPct, good: 0.5, poor: 3 },
   { group: 'tcp-connect', label: 'TCP 建连 p95', key: 'connect.tcp_ms.p95', fmt: fmtMs, optional: true },
   { group: 'tcp-connect', label: 'TLS 握手 p95', key: 'connect.tls_ms.p95', fmt: fmtMs, optional: true },
   { group: 'tcp-connect', label: '建连成功率', key: 'connect.success', fmt: fmtPct, optional: true },
@@ -64,11 +65,11 @@ const GROUPS = [
 
 const CHARTS: ChartDef[] = [
   { id: 'rtt', title: '延迟', group: 'quic', unit: 'ms', series: [{ key: 'rtt.p50', label: 'p50', color: '--chart-1' }, { key: 'rtt.p95', label: 'p95', color: '--chart-2' }, { key: 'rtt.p99', label: 'p99', color: '--chart-3' }] },
-  { id: 'jitter', title: '抖动（p95）', group: 'quic', unit: 'ms', series: [{ key: 'jitter.up.p95', label: '上行', color: '--chart-2' }, { key: 'jitter.down.p95', label: '下行', color: '--chart-1' }] },
-  { id: 'loss', title: '丢包', group: 'quic', unit: '%', series: [{ key: 'loss.up', label: '上行', color: '--chart-2' }, { key: 'loss.down', label: '下行', color: '--chart-3' }, { key: 'loss.total', label: '合计', color: '--chart-1', dash: [4, 3] }] },
-  { id: 'loss-runs', title: '最长连续丢包', group: 'quic', unit: '包', series: [{ key: 'loss.run.up_max', label: '上行', color: '--chart-2' }, { key: 'loss.run.down_max', label: '下行', color: '--chart-3' }] },
+  { id: 'jitter', title: '抖动（p95）', group: 'quic', unit: 'ms', series: [{ key: 'jitter.up.p95', label: '去程', color: '--chart-2' }, { key: 'jitter.down.p95', label: '回程', color: '--chart-1' }] },
+  { id: 'loss', title: '丢包', group: 'quic', unit: '%', series: [{ key: 'loss.up', label: '去程', color: '--chart-2' }, { key: 'loss.down', label: '回程', color: '--chart-3' }, { key: 'loss.total', label: '合计', color: '--chart-1', dash: [4, 3] }] },
+  { id: 'loss-runs', title: '最长连续丢包', group: 'quic', unit: '包', series: [{ key: 'loss.run.up_max', label: '去程', color: '--chart-2' }, { key: 'loss.run.down_max', label: '回程', color: '--chart-3' }] },
   { id: 'tcp', title: '往返时延（RTT）', group: 'tcp-connect', unit: 'ms', series: [{ key: 'tcp.rtt.p50', label: 'p50', color: '--chart-1' }, { key: 'tcp.rtt.p95', label: 'p95', color: '--chart-2' }, { key: 'tcp.rtt.max', label: '最大', color: '--chart-3' }] },
-  { id: 'retrans', title: '重传率', group: 'tcp-connect', unit: '%', fill: true, series: [{ key: 'tcp.retrans', label: '重传率', color: '--chart-3' }] },
+  { id: 'retrans', title: '重传率', group: 'tcp-connect', unit: '%', series: [{ key: 'tcp.retrans.up', label: '去程', color: '--chart-2' }, { key: 'tcp.retrans.down', label: '回程', color: '--chart-3' }, { key: 'tcp.retrans', label: '合计', color: '--chart-1', dash: [4, 3] }] },
   { id: 'connect-time', title: '建连耗时（p95）', group: 'tcp-connect', unit: 'ms', series: [{ key: 'connect.tcp_ms.p95', label: 'TCP 建连', color: '--chart-1' }, { key: 'connect.tls_ms.p95', label: 'TLS 握手', color: '--chart-2' }] },
   { id: 'connect-ok', title: '建连成功率', group: 'tcp-connect', unit: '%', zero: false, series: [{ key: 'connect.success', label: '成功率', color: '--chart-3' }] },
   { id: 'score', title: '综合评分', group: 'score', wide: true, unit: '', series: [{ key: 'score.reality', label: 'REALITY', color: '--chart-1' }, { key: 'score.hy2', label: 'Hy2', color: '--chart-2' }, { key: 'score.mc', label: 'MC', color: '--chart-4' }, { key: 'score.base', label: '综合', color: '--chart-5', dash: [4, 3] }] },
@@ -316,7 +317,7 @@ export function Line() {
               <div className="line-combo-card">
                 <h3>QUIC Datagram 丢包</h3>
                 <div className="line-combo-primary"><span>总丢包</span><strong className={`combo-tone-${tone(m['loss.total'], 0.5, 3)}`}>{fmtPct(m['loss.total'])}</strong></div>
-                <div className="line-combo-secondary"><span>↑ {fmtPct(m['loss.up'])}</span><span>/</span><span>↓ {fmtPct(m['loss.down'])}</span></div>
+                <div className="line-combo-secondary"><span>去 {fmtPct(m['loss.up'])}</span><span>/</span><span>回 {fmtPct(m['loss.down'])}</span></div>
                 <span className="line-combo-badge">最长连续 ↑ {fmtNum(m['loss.run.up_max'])} / ↓ {fmtNum(m['loss.run.down_max'])} 包</span>
               </div>
               <div className="line-combo-card">
diff --git a/web/display/src/pages/Overview.tsx b/web/display/src/pages/Overview.tsx
index 3299065..1f4463c 100644
--- a/web/display/src/pages/Overview.tsx
+++ b/web/display/src/pages/Overview.tsx
@@ -12,7 +12,7 @@ import { PageError } from '../lib'
 import { IPV6_STATES, IpVersionPicker, ipVersionOf } from '@shared/ipVersions'
 import { LineStrips, OVERVIEW_RANGES, type OverviewRange } from '../LineStrips'
 
-const METRICS = ['rtt.p50', 'rtt.p95', 'rtt.p99', 'loss.total', 'loss.up', 'loss.down', 'tcp.rtt.p50', 'tcp.retrans'].join(',')
+const METRICS = ['rtt.p50', 'rtt.p95', 'rtt.p99', 'loss.total', 'loss.up', 'loss.down', 'tcp.rtt.p50', 'tcp.retrans', 'tcp.retrans.up', 'tcp.retrans.down'].join(',')
 
 type SortKey = 'name' | 'rtt' | 'loss'
 
@@ -136,7 +136,7 @@ function NodeCard({ node, labels, infos }: { node: HostItem; labels: string[]; i
   )
 }
 
-/** 一条线路（拨号方 → 监听方）：近一段时间的 QUIC Datagram 上下行丢包、RTT 和 TCP 重传。 */
+/** 一条线路（拨号方 ⇄ 监听方）：RTT 是往返；去程是拨号方到监听方（左到右），回程是监听方到拨号方（右到左）。QUIC 看两个方向的丢包，TCP 看两个方向的重传。 */
 function LineCard({ l, range, infos }: { l: OverviewLineDto; range: OverviewRange; infos: Map<string, NodeInfoDto> }) {
   const dialerInfo = infos.get(l.dialer_id)
   const agentInfo = infos.get(l.agent_id)
@@ -159,7 +159,7 @@ function LineCard({ l, range, infos }: { l: OverviewLineDto; range: OverviewRang
           {dialerInfo?.country ? <Flag code={dialerInfo.country} /> : null}
           <span className="name">{l.dialer_name}</span>
           {dialerInfo?.isp_key ? <IspIcon ispKey={dialerInfo.isp_key} name={dialerInfo.isp_name} /> : null}
-          <span className="arrow">→</span>
+          <span className="arrow" title="RTT 是往返；去程：左 → 右，回程：右 → 左">⇄</span>
           {agentInfo?.country ? <Flag code={agentInfo.country} /> : null}
           <span className="name">{l.name}</span>
         </span>