From c5e92b5cefedbed3fe48d2d6a06f59e07a66fc48 Mon Sep 17 00:00:00 2001
From: mo khan <mo@mokhan.ca>
Date: Mon, 15 Sep 2025 18:58:59 -0600
Subject: Shrink answer 1.4

---
 assignments/1/README.md | 76 +++++++++++++++++++++++--------------------------
 1 file changed, 36 insertions(+), 40 deletions(-)

diff --git a/assignments/1/README.md b/assignments/1/README.md
index 5f6779c..d00afa6 100644
--- a/assignments/1/README.md
+++ b/assignments/1/README.md
@@ -166,49 +166,45 @@ Key Points:
 
 ### Four Types of Network Delays
 
-The following four types of delays occur in packet-switched networks (Kurose & Ross, 2021, Section 1.4.1):
-
-1. Processing Delay (`d_proc`):
-  - Definition: Time required for a router to examine the packet header and determine where to direct the packet
-  - Where it occurs: At routers and switches when they process packet headers
-  - Typical values: Microseconds, depends on router hardware capabilities
-2. Queuing Delay (`d_queue`):
-  - Definition: Time a packet waits in router queues before being transmitted
-  - Where it occurs: In router output buffers when packets wait for transmission
-  - Characteristics: Highly variable, depends on network traffic intensity and congestion
-3. Transmission Delay (`d_trans`):
-  - Definition: Time required to push all packet bits onto the transmission link
-  - Where it occurs: At the sending router when transmitting packet bits
-  - Formula: `d_trans = L/R` (where L = packet length in bits, R = link transmission rate in bps)
-4. Propagation Delay (`d_prop`):
-  - Definition: Time for a signal to propagate from sender to receiver over physical medium
-  - Where it occurs: Along the physical transmission medium (cables, fiber, wireless)
-  - Formula: `d_prop = d/s` (where d = physical distance, s = propagation speed)
+In packet-switched networks, four main delays can occur (Kurose & Ross, 2021):
+
+1. Processing Delay (`d_proc`)
+   * What: Time to examine packet header and determine where to forward it
+   * Where: At routers and switches
+   * Typical duration: Microseconds
+2. Queuing Delay (`d_queue`)
+   * What: Time a packet waits in a queue before being transmitted
+   * Where: In router output queues
+   * Depends on: Network congestion and traffic load
+3. Transmission Delay (`d_trans`)
+   * What: Time to push all bits of the packet onto the link
+   * Where: At the sender’s interface
+   * Formula: `d_trans = L / R`
+     * `L` = packet length (bits)
+     * `R` = link rate (bps)
+4. Propagation Delay (`d_prop`)
+   * What: Time for the signal to travel across the link
+   * Where: Along the transmission medium (e.g., fiber, cable)
+   * Formula: `d_prop = d / s`
+     * `d` = physical distance
+     * `s` = propagation speed
 
 ### Traffic Intensity
 
-Definition: Traffic intensity `(ρ) = La/R` (Kurose & Ross, 2021, Section 1.4.2), where:
-
-- `L` = average packet length (bits)
-- `a` = average packet arrival rate (packets/sec)
-- `R` = transmission rate (bps)
-
-Why Traffic Intensity ≤ 1:
-
-Traffic intensity represents the fraction of time the link is busy transmitting packets. When designing networks:
-
-- ρ < 1: Link can handle the offered traffic load. Average queuing delay remains finite.
-- ρ = 1: Link operates at capacity. Queuing delays become very large and unstable.
-- ρ > 1: Traffic exceeds link capacity. Queues grow without bound, leading to packet loss and network instability.
-
-Design Principle: Networks must be designed with ρ < 1 to ensure:
-
-- Stable operation with bounded delays
-- Ability to handle traffic variations and bursts
-- Acceptable quality of service for applications
-- Prevention of congestion collapse
-
-A safety margin (typically `ρ ≤ 0.7-0.8`) is often used to account for traffic variability and ensure good performance.
+* Definition: `ρ = La / R`
+  * `L` = avg. packet length (bits)
+  * `a` = avg. packet arrival rate (packets/sec)
+  * `R` = link bandwidth (bps)
+* Why `ρ` should be ≤ 1:
+  * If `ρ < 1`: Network can handle the traffic -> delays stay manageable
+  * If `ρ = 1`: Link is fully utilized -> delays increase sharply
+  * If `ρ > 1`: Traffic exceeds capacity -> queues grow indefinitely -> packet loss
+* Design Rule:
+  Keep `ρ < 1` (ideally ≤ 0.7–0.8) for:
+  * Stability
+  * Low delays
+  * Room for bursts
+  * Preventing congestion collapse
 
 ## 1.5 Web Caching (5%)
 
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