support to change rtt dynamically in gym (#12)

* support change rtt dynamically in gym and make a test script

* bugfix : error when handling trace with no rtt and update test script

* remove hardcode in test script about rtt

alphartc_gym/tests/data/rtt/trace_rtt_200.json

@@ -0,0 +1,16 @@
+{
+    "type": "video",
+    "downlink": {},
+    "uplink": {
+        "trace_pattern": [
+            {
+                "duration": 1000,
+                "capacity": 1000,
+                "rtt": 200,
+                "loss": 0,
+                "jitter": 0,
+                "time": 0.0
+            }
+        ]
+    }
+}

alphartc_gym/tests/data/rtt/trace_rtt_400.json

@@ -0,0 +1,16 @@
+{
+    "type": "video",
+    "downlink": {},
+    "uplink": {
+        "trace_pattern": [
+            {
+                "duration": 1000,
+                "capacity": 1000,
+                "rtt": 400,
+                "loss": 0,
+                "jitter": 0,
+                "time": 0.0
+            }
+        ]
+    }
+}

alphartc_gym/tests/data/rtt/trace_rtt_600.json

@@ -0,0 +1,16 @@
+{
+    "type": "video",
+    "downlink": {},
+    "uplink": {
+        "trace_pattern": [
+            {
+                "duration": 1000,
+                "capacity": 1000,
+                "rtt": 600,
+                "loss": 0,
+                "jitter": 0,
+                "time": 0.0
+            }
+        ]
+    }
+}

alphartc_gym/tests/data/rtt/trace_rtt_pattern_2.json

@@ -0,0 +1,24 @@
+{
+    "type": "video",
+    "downlink": {},
+    "uplink": {
+        "trace_pattern": [
+            {
+                "duration": 2000,
+                "capacity": 1000,
+                "loss": 0,
+                "rtt": 200,
+                "jitter": 0,
+                "time": 0.0
+            },
+            {
+                "duration": 2000,
+                "capacity": 1000,
+                "loss": 0,
+                "rtt": 400,
+                "jitter": 0,
+                "time": 0.0
+            }
+        ]
+    }
+}

alphartc_gym/tests/data/rtt/trace_rtt_pattern_3.json

@@ -0,0 +1,32 @@
+{
+    "type": "video",
+    "downlink": {},
+    "uplink": {
+        "trace_pattern": [
+            {
+                "duration": 2000,
+                "capacity": 1000,
+                "loss": 0,
+                "rtt": 200,
+                "jitter": 0,
+                "time": 0.0
+            },
+            {
+                "duration": 2000,
+                "capacity": 1000,
+                "loss": 0,
+                "rtt": 200,
+                "jitter": 0,
+                "time": 0.0
+            },
+            {
+                "duration": 2000,
+                "capacity": 1000,
+                "loss": 0,
+                "rtt": 200,
+                "jitter": 0,
+                "time": 0.0
+            }
+        ]
+    }
+}

alphartc_gym/tests/data/rtt/trace_rtt_pattern_4.json

@@ -0,0 +1,40 @@
+{
+    "type": "video",
+    "downlink": {},
+    "uplink": {
+        "trace_pattern": [
+            {
+                "duration": 2000,
+                "capacity": 1000,
+                "loss": 0,
+                "rtt": 200,
+                "jitter": 0,
+                "time": 0.0
+            },
+            {
+                "duration": 2000,
+                "capacity": 1000,
+                "loss": 0,
+                "rtt": 400,
+                "jitter": 0,
+                "time": 0.0
+            },
+            {
+                "duration": 2000,
+                "capacity": 1000,
+                "loss": 0,
+                "rtt": 300,
+                "jitter": 0,
+                "time": 0.0
+            },
+            {
+                "duration": 2000,
+                "capacity": 1000,
+                "loss": 0,
+                "rtt": 500,
+                "jitter": 0,
+                "time": 0.0
+            }
+        ]
+    }
+}

alphartc_gym/tests/test_gym_rtt.py

@@ -0,0 +1,114 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+
+from alphartc_gym import gym
+import os, json
+
+
+ERROR = 0.05
+
+
+def get_gym_stats(trace_path, duration_time_ms=3000, bandwidth_bps=1000):
+    total_stats = []
+    g = gym.Gym()
+    g.reset(trace_path=trace_path, duration_time_ms=duration_time_ms)
+
+    while True:
+        stats, done = g.step(bandwidth_bps)
+        if not done:
+            total_stats += stats
+        else:
+            return total_stats
+
+
+def cal_pkt_transmit_time_ms(header_bytes, payload_bytes, bw_kps):
+    return (header_bytes + payload_bytes) * 8 / bw_kps
+
+
+def get_info_from_trace(trace_file):
+    with open(trace_file, 'r') as f:
+        return json.loads(f.read())
+
+
+def get_abs_path_by_name(trace_name):
+    trace_path = os.path.join(
+            os.path.dirname(__file__),
+            "data/rtt",
+            trace_name)
+    return trace_path
+
+
+def single_rtt_available(trace_path):
+    total_stats = get_gym_stats(trace_path)
+    assert (total_stats)
+
+    for stats in total_stats:
+        assert (isinstance(stats, dict))
+
+
+def single_rtt_persistence(trace_path):
+    # get information from trace
+    trace_data = get_info_from_trace(trace_path)
+    trace_pattern = trace_data["uplink"]["trace_pattern"]
+    one_way_delay = trace_pattern[0]["rtt"] / 2
+    bandwidth_kbps = trace_pattern[0]["capacity"]
+
+    total_stats = get_gym_stats(trace_path)
+    assert (total_stats)
+
+    for status in total_stats:
+        transmission_delay = cal_pkt_transmit_time_ms(status["header_length"], 
+                                                            status["payload_size"], bw_kps=bandwidth_kbps)
+        predict_arrival_time_ms = status["send_time_ms"] + one_way_delay + transmission_delay
+        assert abs(status["arrival_time_ms"] - predict_arrival_time_ms) <= ERROR * status["arrival_time_ms"]
+
+
+def single_rtt_dynamically(trace_path, run_times=1):
+    # get information from trace
+    trace_data = get_info_from_trace(trace_path)
+    trace_pattern = trace_data["uplink"]["trace_pattern"]
+    one_way_delay_list = sorted([item["rtt"] / 2 for item in trace_pattern])
+    rtt_sample_cnt = [0] * len(one_way_delay_list)
+    bandwidth_kbps = trace_pattern[0]["capacity"]
+    duration_time_ms = sum([item["duration"] for item in trace_pattern]) * run_times
+
+    total_stats = get_gym_stats(trace_path, duration_time_ms=duration_time_ms)
+    assert (total_stats)
+
+    for status in total_stats:
+        transmission_delay = cal_pkt_transmit_time_ms(status["header_length"], 
+                                                            status["payload_size"], bw_kps=bandwidth_kbps)
+        actual_delay = status["arrival_time_ms"] - status["send_time_ms"] - transmission_delay
+        rtt_in_trace = False
+        for i in range(len(one_way_delay_list)):
+            if abs(actual_delay - one_way_delay_list[i]) <= ERROR * one_way_delay_list[i]:
+                rtt_sample_cnt[i] += 1
+                rtt_in_trace = True
+
+        assert rtt_in_trace == True, "actual rtt not exist in trace"
+
+    for i in range(len(rtt_sample_cnt)):
+        assert rtt_sample_cnt[i] > 0
+        if i:
+            assert abs(rtt_sample_cnt[i-1] - rtt_sample_cnt[i]) <= ERROR * rtt_sample_cnt[i]
+
+
+def test_rtt_available():
+    traces_name = ["trace_rtt_200.json", "trace_rtt_400.json", "trace_rtt_600.json"]
+    for trace in traces_name:
+        trace_path = get_abs_path_by_name(trace)
+        single_rtt_available(trace_path)
+
+
+def test_rtt_persistence():
+    traces_name = ["trace_rtt_200.json", "trace_rtt_400.json", "trace_rtt_600.json"]
+    for trace in traces_name:
+        trace_path = get_abs_path_by_name(trace)
+        single_rtt_persistence(trace_path)
+
+
+def test_rtt_dynamically():
+    traces_name = ["trace_rtt_pattern_2.json", "trace_rtt_pattern_3.json", "trace_rtt_pattern_4.json"]
+    for trace in traces_name:
+        trace_path = get_abs_path_by_name(trace)
+        single_rtt_dynamically(trace_path, run_times=20)

ns-app/scratch/webrtc_test/trace_player.cc

@@ -2,6 +2,8 @@
 
 #include "ns3/point-to-point-net-device.h"
 #include "ns3/simulator.h"
+#include "ns3/string.h"
+#include "ns3/channel.h"
 
 #include <nlohmann/json.hpp>
 #include <boost/lexical_cast.hpp>
@@ -40,6 +42,9 @@ void TracePlayer::LoadTrace() {
         TraceItem ti;
         ti.capacity_ = lexical_cast<decltype(ti.capacity_)>(trace["capacity"]);
         ti.duration_ms_ = lexical_cast<decltype(ti.duration_ms_)>(trace["duration"]);
+        if (trace.find("rtt") != trace.end()) {
+            ti.rtt_ms_ = lexical_cast<std::uint64_t>(trace["rtt"]);
+        }        
         traces.push_back(std::move(ti));
     }
     traces_.swap(traces);
@@ -55,6 +60,10 @@ void TracePlayer::PlayTrace(size_t trace_index) {
     const auto &trace = traces_[trace_index];
     for (size_t i = 0; i < nodes_.GetN(); i++) {
         auto node = nodes_.Get(i);
+        // set delay in channel
+        if (trace.rtt_ms_) {
+            node->GetDevice(0)->GetChannel()->SetAttribute("Delay", StringValue(std::to_string(trace.rtt_ms_.value()/2.0) + "ms"));
+        }
         for (size_t j = 0; j < node->GetNDevices(); j++) {
             auto device =
                 dynamic_cast<PointToPointNetDevice *>(PeekPointer(node->GetDevice(j)));

ns-app/scratch/webrtc_test/trace_player.h

@@ -5,10 +5,12 @@
 #include <string>
 #include <cinttypes>
 #include <vector>
+#include <boost/optional.hpp>
 
 struct TraceItem {
     std::uint64_t capacity_;
     std::uint64_t duration_ms_;
+    boost::optional<std::uint64_t> rtt_ms_;
 };
 
 class TracePlayer {