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Module 44
Traffic Policing and Shaping
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# 📘 CCNA 200-301 - Video 44: Traffic Policing and Shaping ## Deep Study Notes --- ## 📌 Learning Objectives By the end of this video, you should understand: - What traffic policing and shaping are - Policing vs. Shaping differences - Traffic policing mechanisms (single-rate, two-rate) - Traffic shaping mechanisms - Configuration examples - When to use policing vs. shaping --- ## 🧠 Core Concepts ### 1. What are Policing and Shaping? **Definition:** Traffic policing and shaping are QoS mechanisms that control the rate of traffic to enforce a configured rate limit (CIR - Committed Information Rate). **Analogy:** Think of policing and shaping like water flow control: - **Policing:** A gate that either lets water through or stops it completely. If too much water comes, it spills over (dropped). - **Shaping:** A reservoir that stores excess water and releases it slowly over time, smoothing out the flow. ``` ┌─────────────────────────────────────────────────────────────────────────────┐ │ POLICING vs. SHAPING │ ├─────────────────────────────────────────────────────────────────────────────┤ │ │ │ POLICING: │ │ ┌─────────────────────────────────────────────────────────────────────┐ │ │ │ │ │ │ │ Incoming Traffic: ████████████████████████████ │ │ │ │ │ │ │ │ │ ▼ │ │ │ │ ┌─────────────────────────────────────────────────────────────┐ │ │ │ │ │ Police (Drop excess) │ │ │ │ │ │ │ │ │ │ │ │ CIR = 1 Mbps │ │ │ │ │ │ Excess traffic: DROPPED │ │ │ │ │ │ │ │ │ │ │ └─────────────────────────────────────────────────────────────┘ │ │ │ │ │ │ │ │ │ ▼ │ │ │ │ Outgoing Traffic: ████████████████████████████ │ │ │ │ (Rate limited, no buffering) │ │ │ │ │ │ │ └─────────────────────────────────────────────────────────────────────┘ │ │ │ │ SHAPING: │ │ ┌─────────────────────────────────────────────────────────────────────┐ │ │ │ │ │ │ │ Incoming Traffic: ████████████████████████████ │ │ │ │ │ │ │ │ │ ▼ │ │ │ │ ┌─────────────────────────────────────────────────────────────┐ │ │ │ │ │ Shaper (Buffer excess) │ │ │ │ │ │ │ │ │ │ │ │ CIR = 1 Mbps │ │ │ │ │ │ Excess traffic: BUFFERED │ │ │ │ │ │ Buffer: [Excess][Excess][Excess] │ │ │ │ │ │ │ │ │ │ │ └─────────────────────────────────────────────────────────────┘ │ │ │ │ │ │ │ │ │ ▼ │ │ │ │ Outgoing Traffic: ████████████████████████████ │ │ │ │ (Rate limited, smoothed) │ │ │ │ │ │ │ └─────────────────────────────────────────────────────────────────────┘ │ │ │ └─────────────────────────────────────────────────────────────────────────────┘ ``` --- ### 2. Policing vs. Shaping Comparison | Feature | Policing | Shaping | |---------|----------|---------| | **Action** | Drops or remarks excess traffic | Buffers excess traffic | | **Direction** | Inbound or outbound | Outbound only | | **Buffer** | No buffer (or limited) | Uses buffer (queue) | | **Delay** | No added delay | Adds delay (buffering) | | **Effect** | Hard rate limit | Smooths traffic bursts | | **Best For** | Enforcing strict limits, ingress | Egress, meeting CIR, provider links | | **Resource Usage** | Lower CPU/memory | Higher CPU/memory | | **Retransmission** | Relies on TCP retransmission | May cause TCP timeouts if buffer too large | ``` ┌─────────────────────────────────────────────────────────────────────────────┐ │ POLICING vs. SHAPING GRAPHICAL │ ├─────────────────────────────────────────────────────────────────────────────┤ │ │ │ INGRESS TRAFFIC (Bursty): │ │ ┌─────────────────────────────────────────────────────────────────────┐ │ │ │ Rate │ │ │ │ │ │ │ │ │ 1M│ ████ │ │ │ │ │ ████ │ │ │ │ 800K│ ████ ████ │ │ │ │ │ ████ ████ │ │ │ │ 600K│ ████ ████ ████ │ │ │ │ │ ████ ████ ████ │ │ │ │ 400K│ ████ ████ ████ ████ │ │ │ │ │ ████ ████ ████ ████ │ │ │ │ 200K│ ████ ████ ████ ████ ████ │ │ │ │ │ ████ ████ ████ ████ ████ │ │ │ │ └──────────────────────────────────────────────────► Time │ │ │ └─────────────────────────────────────────────────────────────────────┘ │ │ │ │ AFTER POLICING (Drop Excess): │ │ ┌─────────────────────────────────────────────────────────────────────┐ │ │ │ Rate │ │ │ │ │ │ │ │ │ 1M│ ████ │ │ │ │ │ ████ │ │ │ │ 800K│ ████ ████ │ │ │ │ │ ████ ████ │ │ │ │ 600K│ ████ ████ ████ │ │ │ │ │ ████ ████ ████ │ │ │ │ 400K│ ████ ████ ████ ████ │ │ │ │ │ ████ ████ ████ ████ │ │ │ │ 200K│ ████ ████ ████ ████ X │ │ │ │ │ ████ ████ ████ ████ X │ │ │ │ └──────────────────────────────────────────────────► Time │ │ │ │ X = Dropped packet │ │ │ └─────────────────────────────────────────────────────────────────────┘ │ │ │ │ AFTER SHAPING (Buffer Excess): │ │ ┌─────────────────────────────────────────────────────────────────────┐ │ │ │ Rate │ │ │ │ │ │ │ │ │ 1M│ │ │ │ │ │ │ │ │ │ 800K│ │ │ │ │ │ │ │ │ │ 600K│ │ │ │ │ │ │ │ │ │ 400K│ │ │ │ │ │ │ │ │ │ 200K│ ████ ████ ████ ████ ████ ████ ████ ████ │ │ │ │ │ ████ ████ ████ ████ ████ ████ ████ ████ │ │ │ │ └──────────────────────────────────────────────────► Time │ │ │ │ │ │ │ │ Traffic is smoothed, bursts are buffered and transmitted later │ │ │ │ │ │ │ └─────────────────────────────────────────────────────────────────────┘ │ │ │ └─────────────────────────────────────────────────────────────────────────────┘ ``` --- ### 3. Traffic Polishing (Policing) **Policing Terminology:** | Term | Description | |------|-------------| | **CIR (Committed Information Rate)** | Guaranteed rate (bits per second) | | **CBS (Committed Burst Size)** | Amount of traffic that can burst within CIR | | **EIR (Excess Information Rate)** | Rate above CIR that can be sent (if available) | | **EBS (Excess Burst Size)** | Amount of traffic that can burst above CIR | | **Conform Action** | Action for traffic within CIR (transmit) | | **Exceed Action** | Action for traffic above CIR but within EIR (drop/remark) | | **Violate Action** | Action for traffic above EIR (drop) | ``` ┌─────────────────────────────────────────────────────────────────────────────┐ │ POLICING BUCKET MODEL │ ├─────────────────────────────────────────────────────────────────────────────┤ │ │ │ Token Bucket Model: │ │ ┌─────────────────────────────────────────────────────────────────────┐ │ │ │ │ │ │ │ Tokens added at rate CIR │ │ │ │ │ │ │ │ │ ▼ │ │ │ │ ┌─────────────────────────────────────────────────────────────┐ │ │ │ │ │ Token Bucket │ │ │ │ │ │ (CBS) │ │ │ │ │ │ │ │ │ │ │ │ Tokens: [T][T][T][T][T] │ │ │ │ │ │ │ │ │ │ │ └─────────────────────────────────────────────────────────────┘ │ │ │ │ │ │ │ │ │ │ Packet arrives, consumes tokens │ │ │ │ ▼ │ │ │ │ ┌─────────────────────────────────────────────────────────────┐ │ │ │ │ │ If tokens available: Conform (transmit) │ │ │ │ │ │ If no tokens: Exceed (drop or remark) │ │ │ │ │ └─────────────────────────────────────────────────────────────┘ │ │ │ │ │ │ │ └─────────────────────────────────────────────────────────────────────┘ │ │ │ └─────────────────────────────────────────────────────────────────────────────┘ ``` --- ### 4. Policing Configuration **Single-Rate Policing (CIR only):** ```cisco ! Police traffic to 1 Mbps, burst 8000 bytes policy-map POLICE-1MB class class-default police 1000000 8000 conform-action transmit exceed-action drop interface GigabitEthernet0/0 service-policy input POLICE-1MB ``` **Two-Rate Policing (CIR + PIR):** ```cisco ! Two-rate policing: CIR 1 Mbps, PIR 2 Mbps policy-map POLICE-2RATE class class-default police cir 1000000 pir 2000000 conform-action transmit exceed-action set-dscp-transmit af11 violate-action drop interface GigabitEthernet0/0 service-policy input POLICE-2RATE ``` **Policing with Remarking:** ```cisco ! Police and remark excess traffic policy-map POLICE-REMARK class class-default police 1000000 8000 conform-action transmit exceed-action set-dscp-transmit af11 violate-action drop interface GigabitEthernet0/0 service-policy input POLICE-REMARK ``` --- ### 5. Traffic Shaping Configuration **Basic Shaping:** ```cisco ! Shape traffic to 10 Mbps policy-map SHAPE-10MB class class-default shape average 10000000 interface Serial0/0/0 service-policy output SHAPE-10MB ``` **Shaping with Hierarchical Policy (Parent-Child):** ```cisco ! Parent policy for shaping, child for queuing policy-map SHAPE-PARENT class class-default shape average 10000000 service-policy QUEUE-CHILD policy-map QUEUE-CHILD class VOICE priority percent 30 class VIDEO bandwidth percent 25 class DATA bandwidth percent 20 class class-default fair-queue interface Serial0/0/0 service-policy output SHAPE-PARENT ``` **Shaping with Adaptive Shaping (Frame Relay):** ```cisco ! Adaptive shaping based on BECN (Frame Relay) policy-map SHAPE-ADAPTIVE class class-default shape average 1000000 shape adaptive 500000 ! Drop to 500k when congestion detected interface Serial0/0/0 encapsulation frame-relay service-policy output SHAPE-ADAPTIVE ``` --- ### 6. Policing vs. Shaping Use Cases ``` ┌─────────────────────────────────────────────────────────────────────────────┐ │ WHEN TO USE POLICING vs. SHAPING │ ├─────────────────────────────────────────────────────────────────────────────┤ │ │ │ USE POLICING WHEN: │ │ ┌─────────────────────────────────────────────────────────────────────┐ │ │ │ • Enforcing strict rate limits (ISP ingress) │ │ │ │ • Preventing a customer from exceeding their CIR │ │ │ │ • Protecting network from DoS attacks │ │ │ │ • Ingress traffic (cannot buffer what hasn't arrived) │ │ │ │ • Marking down traffic (remark) │ │ │ │ • Simple, low-overhead rate limiting │ │ │ └─────────────────────────────────────────────────────────────────────┘ │ │ │ │ USE SHAPING WHEN: │ │ ┌─────────────────────────────────────────────────────────────────────┐ │ │ │ • Matching service provider CIR (avoid packet drops) │ │ │ │ • Smoothing bursty traffic (prevent tail drops) │ │ │ │ • Outbound traffic on WAN links │ │ │ │ • Frame Relay/ATM networks (BECN adaptation) │ │ │ │ • When buffering is acceptable (delay-tolerant traffic) │ │ │ │ • Meeting SLA commitments │ │ │ └─────────────────────────────────────────────────────────────────────┘ │ │ │ └─────────────────────────────────────────────────────────────────────────────┘ ``` --- ### 7. Policing and Shaping Verification | Command | Purpose | |---------|---------| | `show policy-map interface [int]` | Display policing/shaping statistics | | `show policy-map` | Display policy map configuration | | `show interfaces [int]` | Display interface drops | | `show queueing interface [int]` | Display shaping queue statistics | **Example Outputs:** ```cisco Router# show policy-map interface serial 0/0/0 Serial0/0/0 Service-policy output: SHAPE-10MB Class-map: class-default (match-any) 12345 packets, 12345678 bytes 5 minute offered rate 5000000 bps, drop rate 0 bps Match: any Traffic Shaping Target/Average Peak Rate Excess Rate Limit Bits/Int 10000000 31250 10000000 10000000 Adapt Queue Packets Bytes Packets Bytes Shaping Active Depth Delayed Delayed Active - 0 12345 12345678 0 0 no Router# show policy-map interface gigabitEthernet 0/0 GigabitEthernet0/0 Service-policy input: POLICE-1MB Class-map: class-default (match-any) 56789 packets, 56789012 bytes 5 minute offered rate 2000000 bps, drop rate 500000 bps Match: any police: cir 1000000 bps, bc 8000 bytes conformed 23456 packets, 23456789 bytes; actions: transmit exceeded 12345 packets, 12345678 bytes; actions: drop violated 0 packets, 0 bytes; actions: drop conformed 1000000 bps, exceed 500000 bps, violate 0 bps ``` --- ### 8. Policing and Shaping Burst Size Calculation **Burst Size Formula:** ``` Bc (Committed Burst) = CIR × Tc Where: - Bc = Committed Burst (bytes) - CIR = Committed Information Rate (bps) - Tc = Time interval (seconds) Example: CIR = 1,000,000 bps (1 Mbps) Tc = 0.008 seconds (8 ms) Bc = 1,000,000 × 0.008 = 8,000 bytes ``` ``` ┌─────────────────────────────────────────────────────────────────────────────┐ │ BURST SIZE CALCULATION │ ├─────────────────────────────────────────────────────────────────────────────┤ │ │ │ Recommended Burst Sizes: │ │ ┌─────────────────────────────────────────────────────────────────────┐ │ │ │ │ │ │ │ CIR (Mbps) │ Bc (Bytes) │ Tc (ms) │ │ │ │ ─────────────────────────────────────────────────────────────────│ │ │ │ 1.5 (T1) │ 12,000 │ 64 │ │ │ │ 2 │ 16,000 │ 64 │ │ │ │ 5 │ 40,000 │ 64 │ │ │ │ 10 │ 80,000 │ 64 │ │ │ │ 45 (DS3) │ 360,000 │ 64 │ │ │ │ 100 │ 800,000 │ 64 │ │ │ │ │ │ │ │ Formula: Bc = (CIR × Tc) / 8 │ │ │ │ Where Tc = 64 ms = 0.064 seconds │ │ │ │ │ │ │ └─────────────────────────────────────────────────────────────────────┘ │ │ │ └─────────────────────────────────────────────────────────────────────────────┘ ``` --- ### 9. Advanced Policing: Percentage-Based ```cisco ! Percentage-based policing (based on interface bandwidth) policy-map POLICE-PERCENT class class-default police percent 50 conform-action transmit exceed-action drop interface GigabitEthernet0/0 bandwidth 10000000 ! 10 Mbps service-policy input POLICE-PERCENT ! This will police to 50% of 10 Mbps = 5 Mbps ``` --- ### 10. Hierarchical QoS (HQoS) ``` ┌─────────────────────────────────────────────────────────────────────────────┐ │ HIERARCHICAL QoS (HQoS) │ ├─────────────────────────────────────────────────────────────────────────────┤ │ │ │ Parent Policy (Shaping): │ │ ┌─────────────────────────────────────────────────────────────────────┐ │ │ │ │ │ │ │ policy-map SHAPE-PARENT │ │ │ │ class class-default │ │ │ │ shape average 10000000 │ │ │ │ service-policy QUEUE-CHILD │ │ │ │ │ │ │ └─────────────────────────────────────────────────────────────────────┘ │ │ │ │ │ ▼ │ │ Child Policy (Queuing): │ │ ┌─────────────────────────────────────────────────────────────────────┐ │ │ │ │ │ │ │ policy-map QUEUE-CHILD │ │ │ │ class VOICE │ │ │ │ priority percent 30 │ │ │ │ class VIDEO │ │ │ │ bandwidth percent 25 │ │ │ │ class DATA │ │ │ │ bandwidth percent 20 │ │ │ │ class class-default │ │ │ │ fair-queue │ │ │ │ │ │ │ └─────────────────────────────────────────────────────────────────────┘ │ │ │ │ Benefits: │ │ ┌─────────────────────────────────────────────────────────────────────┐ │ │ │ • Shape total traffic to match CIR │ │ │ │ • Within shaped traffic, prioritize classes │ │ │ │ • Efficient bandwidth utilization │ │ │ └─────────────────────────────────────────────────────────────────────┘ │ │ │ └─────────────────────────────────────────────────────────────────────────────┘ ``` --- ## 🔧 Complete Configuration Examples ### Lab 1: Simple Policing (Drop Excess) ```cisco ! Police inbound traffic to 10 Mbps, drop excess policy-map POLICE-INGRESS class class-default police 10000000 80000 conform-action transmit exceed-action drop interface GigabitEthernet0/0 service-policy input POLICE-INGRESS ``` --- ### Lab 2: Policing with Remarking (Two-Rate) ```cisco ! Two-rate policing: CIR 5 Mbps, PIR 10 Mbps ! Conform: transmit ! Exceed: remark to AF11 ! Violate: drop policy-map POLICE-2RATE-REMARK class class-default police cir 5000000 pir 10000000 conform-action transmit exceed-action set-dscp-transmit af11 violate-action drop interface GigabitEthernet0/0 service-policy input POLICE-2RATE-REMARK ``` --- ### Lab 3: Basic Traffic Shaping ```cisco ! Shape outbound traffic to 10 Mbps policy-map SHAPE-OUTBOUND class class-default shape average 10000000 interface Serial0/0/0 service-policy output SHAPE-OUTBOUND ``` --- ### Lab 4: Hierarchical QoS (Shaping + Queuing) ```cisco ! Class maps class-map VOICE match dscp ef class-map VIDEO match dscp af41 class-map DATA match dscp af31 ! Child policy (queuing) policy-map QUEUE-POLICY class VOICE priority percent 30 class VIDEO bandwidth percent 25 class DATA bandwidth percent 20 class class-default fair-queue ! Parent policy (shaping) policy-map SHAPE-POLICY class class-default shape average 10000000 service-policy QUEUE-POLICY interface Serial0/0/0 service-policy output SHAPE-POLICY ``` --- ### Lab 5: Frame Relay Traffic Shaping ```cisco ! Frame Relay traffic shaping with adaptive shaping policy-map FR-SHAPE class class-default shape average 512000 shape adaptive 256000 ! Reduce to 256k when BECN received shape fecn-adapt interface Serial0/0/0 encapsulation frame-relay frame-relay traffic-shaping service-policy output FR-SHAPE ! Map to specific DLCI map-class frame-relay FR-CLASS frame-relay cir 512000 frame-relay bc 8000 frame-relay be 8000 frame-relay adaptive-shaping becn interface Serial0/0/0.1 point-to-point frame-relay interface-dlci 100 class FR-CLASS ``` --- ### Lab 6: Percentage-Based Policing ```cisco ! Police to 50% of interface bandwidth interface GigabitEthernet0/0 bandwidth 10000000 ! 10 Mbps policy-map POLICE-PERCENT class class-default police percent 50 conform-action transmit exceed-action drop interface GigabitEthernet0/0 service-policy input POLICE-PERCENT ``` --- ## ✅ Exam Tips (For CCNA 200-301) | Topic | What Cisco Tests | |-------|------------------| | **Policing** | Drops excess traffic, inbound/outbound, no buffer | | **Shaping** | Buffers excess traffic, outbound only, adds delay | | **CIR** | Committed Information Rate (guaranteed rate) | | **Bc** | Committed Burst (amount of traffic allowed in time interval) | | **Conform Action** | Traffic within CIR (transmit) | | **Exceed Action** | Traffic above CIR (drop/remark) | | **Hierarchical QoS** | Shaping (parent) + Queuing (child) | ### Common Exam Scenarios: **Scenario 1:** "A customer has a 10 Mbps circuit but only purchased 5 Mbps. The ISP wants to drop all traffic above 5 Mbps. Which QoS tool should be used?" - **Answer:** Policing (ingress on ISP router) **Scenario 2:** "A branch office has a 10 Mbps WAN link but needs to shape traffic to 5 Mbps to match the service provider's CIR. Which QoS tool should be used?" - **Answer:** Shaping (outbound on customer router) **Scenario 3:** "What is the difference between policing and shaping in terms of buffering?" - **Answer:** Policing does not buffer (drops excess); shaping buffers excess traffic ### Mnemonics: **Policing vs. Shaping:** **"P for Police, S for Store"** - **P**olicing: **P**unish (drop) excess traffic - **S**haping: **S**tore (buffer) excess traffic **Policing Actions:** **"C.E.V." - Conform, Exceed, Violate** - **C**onform: Within CIR (transmit) - **E**xceed: Above CIR but within PIR (drop/remark) - **V**iolate: Above PIR (drop) --- ## 📝 Summary (1-Minute Revision) ``` TRAFFIC POLICING AND SHAPING: POLICING: ├── Action: Drops or remarks excess traffic ├── Direction: Inbound or outbound ├── Buffer: None (or minimal) ├── Delay: No added delay ├── Use: Enforcing strict limits, ingress └── Command: police [cir] [bc] conform-action exceed-action SHAPING: ├── Action: Buffers excess traffic ├── Direction: Outbound only ├── Buffer: Uses queue ├── Delay: Adds delay ├── Use: Matching CIR, smoothing bursts └── Command: shape average [cir] KEY TERMS: ├── CIR: Committed Information Rate (guaranteed) ├── PIR: Peak Information Rate (maximum allowed) ├── Bc: Committed Burst (tokens per interval) ├── Be: Excess Burst (additional tokens) ├── Conform: Within CIR (transmit) ├── Exceed: Above CIR (drop/remark) └── Violate: Above PIR (drop) CONFIGURATION: ├── police [cir] [bc] conform-action [action] exceed-action [action] ├── shape average [cir] [bc] ├── shape adaptive [cir] (Frame Relay) └── hierarchical: shape average + service-policy VERIFICATION: ├── show policy-map interface ├── show policy-map └── show queueing interface ``` --- ## 🧪 Practice Questions **1. What is the primary difference between policing and shaping?** - A) Policing buffers, shaping drops - B) Policing drops, shaping buffers - C) Both buffer traffic - D) Both drop traffic <details> <summary>Answer</summary> <b>B) Policing drops, shaping buffers</b> - Policing drops excess traffic, shaping buffers it. </details> **2. Which direction can shaping be applied?** - A) Inbound only - B) Outbound only - C) Both inbound and outbound - D) Neither <details> <summary>Answer</summary> <b>B) Outbound only</b> - Shaping can only be applied to outbound traffic. </details> **3. What does CIR stand for?** - A) Committed Information Rate - B) Committed Internet Rate - C) Constant Information Rate - D) Configurable Information Rate <details> <summary>Answer</summary> <b>A) Committed Information Rate</b> - The guaranteed rate of traffic. </details> **4. Which QoS tool adds delay to traffic?** - A) Policing - B) Shaping - C) Marking - D) Classification <details> <summary>Answer</summary> <b>B) Shaping</b> - Shaping buffers traffic, adding delay. </details> **5. Which command configures traffic shaping?** - A) `police` - B) `shape average` - C) `bandwidth` - D) `priority` <details> <summary>Answer</summary> <b>B) `shape average`</b> - Configures traffic shaping. </details> **6. What is the typical action for conforming traffic?** - A) Drop - B) Transmit - C) Remark - D) Queue <details> <summary>Answer</summary> <b>B) Transmit</b> - Conforming traffic is within the CIR and is transmitted. </details> **7. Which QoS tool is typically used on ingress to prevent DoS attacks?** - A) Shaping - B) Policing - C) Queuing - D) WRED <details> <summary>Answer</summary> <b>B) Policing</b> - Policing can be applied inbound to drop excess traffic. </details> **8. What is the purpose of hierarchical QoS?** - A) Combine shaping and queuing - B) Combine policing and shaping - C) Combine marking and queuing - D) Combine classification and marking <details> <summary>Answer</summary> <b>A) Combine shaping and queuing</b> - Parent policy shapes, child policy queues. </details> **9. Which command displays policing statistics on an interface?** - A) `show policy-map interface` - B) `show shaping` - C) `show policing` - D) `show queue` <details> <summary>Answer</summary> <b>A) `show policy-map interface`</b> - Displays policing/shaping statistics. </details> **10. What is the recommended burst size for a 10 Mbps shaped link?** - A) 8,000 bytes - B) 40,000 bytes - C) 80,000 bytes - D) 800,000 bytes <details> <summary>Answer</summary> <b>C) 80,000 bytes</b> - 10 Mbps × 64 ms = 80,000 bytes. </details> **11. Which QoS tool is better suited for meeting a service provider's CIR?** - A) Policing - B) Shaping - C) Marking - D) WRED <details> <summary>Answer</summary> <b>B) Shaping</b> - Shaping smooths bursts to match CIR and avoid packet drops. </details> **12. What happens to traffic that exceeds the PIR?** - A) Transmitted - B) Buffered - C) Dropped - D) Remarked <details> <summary>Answer</summary> <b>C) Dropped</b> - Traffic exceeding PIR is typically dropped (violate action). </details> --- ## 📌 Next Steps After completing Video 44, you should be ready for: - **Video 45:** QoS Configuration Examples - **Video 46:** CDP and LLDP **Lab Practice:** 1. Configure policing to limit inbound traffic to 10 Mbps 2. Configure shaping to limit outbound traffic to 5 Mbps 3. Verify with `show policy-map interface` 4. Test with traffic generator 5. Configure hierarchical QoS (shaping + LLQ) 6. Compare policing vs. shaping with bursty traffic --- **Ready for Video 45?** Share the link or say "next" and I'll continue with QoS Configuration Examples. I'll continue with **Video 45: QoS Configuration Examples** based on the standard CCNA 200-301 curriculum. ---