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QoS, Monitoring & Network Assurance (350-401 ENCOR) Flashcards
Cisco CCNP Enterprise 350-401-ENCOR Flashcards
Study our QoS, Monitoring & Network Assurance (350-401 ENCOR) flashcards for the Cisco CCNP Enterprise 350-401-ENCOR exam with 60+ flashcards. View as flashcards, a searchable table, or as a fun matching game.
| Front | Back |
| Active monitoring | Synthetic probes such as ping iperf and synthetic transactions to measure performance |
| AF definition | Assured Forwarding DSCP classes with drop precedence levels |
| Assurance validation steps | Define SLO SLAs collect baseline apply tests and iterate remediation based on telemetry |
| Bufferbloat definition | Excessive buffering causing high latency and jitter under load |
| CBS meaning | Committed Burst Size maximum burst allowed above committed rate |
| CBWFQ definition | Class Based Weighted Fair Queuing allocates bandwidth to traffic classes with FIFO within class |
| CIR definition | Committed Information Rate the guaranteed bandwidth in policing or shaping |
| Class map purpose | Match traffic based on access lists dscp cos or protocols |
| Classification purpose | Identify and group traffic for policy enforcement |
| CoS definition | 3 bit Layer2 priority used in Ethernet VLAN tagged frames |
| Default DSCP for best effort | CS0 or DSCP 0 |
| DSCP definition | 6 bit IP header field used for packet marking and forwarding treatment |
| DSCP preservation troubleshooting | Check trust boundaries marking policies and MPLS EXP mapping across devices |
| ECN function | Explicit Congestion Notification marks IP header instead of dropping packets to signal congestion |
| EF meaning | Expedited Forwarding DSCP for low latency low jitter traffic typically voice |
| Exporter sampling rate impact | Lower sampling rate reduces export overhead but decreases fidelity of flow data |
| Hardware Queues vs software queues | Hardware queues are on ASICs faster and limited count software queues are flexible but slower |
| Hierarchical QoS purpose | Apply QoS policies at multiple levels such as per interface and per class for complex policies |
| How to validate QoS policies | Use packet captures DSCP counters NetFlow telemetry and synthetic tests to confirm behavior |
| Jitter definition | Variation in packet arrival time usually measured as delay variation |
| LLQ definition | Low Latency Queue strict priority queue with policing to protect bandwidth |
| Marking methods | DSCP CoS MPLS EXP |
| Model driven telemetry vs CLI parsing | Model driven uses YANG models and structured data more reliable than CLI parsing |
| MOS meaning | Mean Opinion Score user perceived voice quality from 1 worst to 5 best |
| MQC components | Modular QoS CLI uses class map policy map and service policy |
| NetFlow exporter collector roles | Exporter on device sends flow records collector stores and analyzes flows |
| NetFlow versions | Common NetFlow v5 v9 and IPFIX v10 template based flexible formats |
| One way delay vs RTT | One way delay measures single direction latency RTT measures round trip time both needed for troubleshooting |
| Outbound vs inbound policing | Policing on inbound can drop before crossing device shaping on outbound controls egress rate |
| Packet capture use | Use Wireshark or tcpdump to analyze packet headers timestamps and DSCP preservation |
| Packet loss causes | Congestion faulty hardware MTU mismatch or misconfigured QoS policies |
| Passive monitoring | Observing live traffic flows using NetFlow sFlow or packet capture without injecting probes |
| Path MTU discovery purpose | Determine largest packet size that can traverse path without fragmentation |
| Performance baseline purpose | Establish expected traffic patterns and metrics to compare during incidents |
| Policing action remark | Policing may remark DSCP to lower priority instead of dropping excess packets |
| Policing colors explanation | Colors green yellow red indicate conforming partially conforming and exceeding packets for remarking or drop |
| Policing vs shaping difference | Policing drops or remarks excess packets shaping buffers and delays to conform |
| Policy map purpose | Define actions such as mark police shape and queue for matched classes |
| PQ definition | Priority Queuing processes highest priority queue first possibly starving lower queues |
| R factor | E Model score mapping to MOS for voice quality assessment |
| RTCP XR use | RTCP Extended Reports provide detailed voice quality metrics such as loss jitter and MOS estimates |
| Service policy purpose | Attach policy map to interface inbound or outbound to enforce QoS |
| sFlow sampling concept | Packet sampling and counter polling for scalable flow accounting |
| Shaping effect on latency | Shaping can increase latency but reduces packet loss by smoothing bursts |
| Shaping recommended location | Shaping on egress links close to congestion point such as WAN interfaces |
| Show command for QoS counters | show policy interface displays class statistics queue drops and rates |
| SNMP MIB OID | MIB stores manageable objects OID is numeric identifier for each object |
| SNMP purpose | Simple Network Management Protocol collects device metrics and sends traps |
| SNMP v3 advantage | Adds authentication and encryption for secure management |
| Tail drop vs WRED difference | Tail drop drops packets when buffer full WRED randomly drops lower priority packets earlier |
| Telemetry protocols | gNMI gRPC RESTCONF NETCONF and streaming telemetry using gRPC |
| Telemetry streaming benefit | Continuous push of rich structured data lower overhead and real time insight |
| Token bucket concept | Tokens accumulate allowing bursts up to bucket size while enforcing average rate |
| Traceroute use in performance | Identify per hop latency and packet loss to isolate problem segment |
| Trust boundary concept | Point where device trusts or re marks incoming trust field such as DSCP or CoS |
| Useful debug commands | show interfaces show controllers show platform hardware and packet captures for troubleshooting |
| WFQ definition | Weighted Fair Queuing schedules packets based on flow weights to share bandwidth fairly |
| What is QoS goal? | Prioritize and manage network resources to meet application performance requirements |
| WRED parameters | WRED uses min threshold max threshold and drop probability to randomize drops |
| WRED purpose | Prevent global synchronization and favor higher priority traffic during congestion |
About the Flashcards
Flashcards for the Cisco CCNP Enterprise exam sharpen your grasp of network Quality of Service by guiding you through QoS goals, traffic classification, DSCP and CoS marking, and priority handling such as EF, AF, LLQ, and CBWFQ. You will quickly recall how policing, shaping, token buckets, CIR, and hierarchical policies guarantee committed rates and manage congestion effectively.
The deck also reinforces the measurement and assurance skills tested on the exam, including NetFlow, sFlow, SNMP, model-driven telemetry, and active versus passive monitoring. Review key performance metrics like jitter, MOS, and R-factor, compare tail drop with WRED, and practice show and debug commands that validate trust boundaries and policy effectiveness.
Topics covered in this flashcard deck:
- QoS fundamentals
- Traffic marking methods
- Queuing & congestion management
- Flow monitoring protocols
- Performance metrics & troubleshooting