diff --git a/simulations/Cargo.toml b/simulations/Cargo.toml
index 86ef6f5f..e33ecbcc 100644
--- a/simulations/Cargo.toml
+++ b/simulations/Cargo.toml
@@ -21,6 +21,7 @@ crossbeam = { version = "0.8.2", features = ["crossbeam-channel"] }
 consensus-engine = { path = "../consensus-engine" }
 fixed-slice-deque = "0.1.0-beta2"
 futures = "0.3"
+humantime = "2.1"
 humantime-serde = "1"
 nomos-core = { path = "../nomos-core" }
 nomos-consensus = { path = "../nomos-services/consensus" }
diff --git a/simulations/config/carnot.json b/simulations/config/carnot.json
index da92b5cf..483f4a01 100644
--- a/simulations/config/carnot.json
+++ b/simulations/config/carnot.json
@@ -1,42 +1,15 @@
 {
   "network_settings": {
     "network_behaviors": {
-      "north america:north america": {
-        "secs": 1,
-        "nanos": 0
-      },
-      "north america:europe": {
-        "secs": 1,
-        "nanos": 0
-      },
-      "north america:asia": {
-        "secs": 1,
-        "nanos": 0
-      },
-      "europe:europe": {
-        "secs": 1,
-        "nanos": 0
-      },
-      "europe:asia": {
-        "secs": 1,
-        "nanos": 0
-      },
-      "europe:north america": {
-        "secs": 1,
-        "nanos": 0
-      },
-      "asia:north america": {
-        "secs": 1,
-        "nanos": 0
-      },
-      "asia:europe": {
-        "secs": 1,
-        "nanos": 0
-      },
-      "asia:asia": {
-        "secs": 1,
-        "nanos": 0
-      }
+      "north america:north america": "1s",
+      "north america:europe": "1s",
+      "north america:asia": "1s",
+      "europe:europe": "1s",
+      "europe:asia": "1s",
+      "europe:north america": "1s",
+      "asia:north america": "1s",
+      "asia:europe": "1s",
+      "asia:asia": "1s"
     },
     "regions": {
       "north america": 0.4,
diff --git a/simulations/src/network/mod.rs b/simulations/src/network/mod.rs
index 52e8e163..347c4257 100644
--- a/simulations/src/network/mod.rs
+++ b/simulations/src/network/mod.rs
@@ -56,12 +56,51 @@ impl<'de> Deserialize<'de> for NetworkBehaviourKey {
 
 #[derive(Clone, Debug, Serialize, Deserialize, Default)]
 pub struct NetworkSettings {
+    #[serde(with = "network_behaviors_serde")]
     pub network_behaviors: HashMap<NetworkBehaviourKey, Duration>,
     /// Represents node distribution in the simulated regions.
     /// The sum of distributions should be 1.
     pub regions: HashMap<regions::Region, f32>,
 }
 
+/// Ser/Deser `HashMap<NetworkBehaviourKey, Duration>` to humantime format.
+mod network_behaviors_serde {
+    use super::{Deserialize, Duration, HashMap, NetworkBehaviourKey};
+
+    /// Have to implement this manually because of the `serde_json` will panic if the key of map
+    /// is not a string.
+    pub fn serialize<S>(
+        vals: &HashMap<NetworkBehaviourKey, Duration>,
+        serializer: S,
+    ) -> Result<S::Ok, S::Error>
+    where
+        S: serde::Serializer,
+    {
+        use serde::ser::SerializeMap;
+        let mut ser = serializer.serialize_map(Some(vals.len()))?;
+        for (k, v) in vals {
+            ser.serialize_key(&k)?;
+            ser.serialize_value(&humantime::format_duration(*v).to_string())?;
+        }
+        ser.end()
+    }
+
+    pub fn deserialize<'de, D>(
+        deserializer: D,
+    ) -> Result<HashMap<NetworkBehaviourKey, Duration>, D::Error>
+    where
+        D: serde::Deserializer<'de>,
+    {
+        let map = HashMap::<NetworkBehaviourKey, String>::deserialize(deserializer)?;
+        map.into_iter()
+            .map(|(k, v)| {
+                let v = humantime::parse_duration(&v).map_err(serde::de::Error::custom)?;
+                Ok((k, v))
+            })
+            .collect::<Result<HashMap<_, _>, _>>()
+    }
+}
+
 pub struct Network<M> {
     pub regions: regions::RegionsData,
     network_time: NetworkTime,
diff --git a/simulations/src/runner/mod.rs b/simulations/src/runner/mod.rs
index 5d265f16..c65a4c91 100644
--- a/simulations/src/runner/mod.rs
+++ b/simulations/src/runner/mod.rs
@@ -148,6 +148,7 @@ where
             views_count: _,
             leaders_count: _,
             network_settings: _,
+            step_time: _,
         } = settings;
         Ok(Self {
             runner_settings,
diff --git a/simulations/src/settings.rs b/simulations/src/settings.rs
index 6157b330..f30cba0f 100644
--- a/simulations/src/settings.rs
+++ b/simulations/src/settings.rs
@@ -42,6 +42,8 @@ pub struct SimulationSettings {
     #[serde(default)]
     pub runner_settings: RunnerSettings,
     pub stream_settings: StreamSettings,
+    #[serde(with = "humantime_serde")]
+    pub step_time: std::time::Duration,
     pub node_count: usize,
     pub views_count: usize,
     pub leaders_count: usize,