Ping Labz (Page 3)

EIGRP Metric and K Values Explained

The EIGRP composite metric formula, the five K values and why never to change them, the 64-bit wide metric for modern interfaces, and how to verify metrics in show output.

5 min read Apr 26, 2026

EIGRP public

EIGRP DUAL Algorithm Deep Dive: Successors, Feasible Successors, FD, RD

J

DUAL gives EIGRP sub-second failover via pre-computed feasible successors. The four key concepts (successor, FS, FD, RD), the feasibility condition that prevents loops, active states, and queries.

6 min read Apr 26, 2026

QoS public

QoS in Modern Networks: SD-WAN, Cloud, and Application-Aware Steering

J

QoS in 2026 is application-aware steering at the SD-WAN edge plus local queueing per tunnel. Why DSCP stops being honored at administrative boundaries, and how SD-WAN path conditioning compensates.

7 min read Apr 25, 2026

QoS public

Voice and Video QoS on Cisco IOS XE

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Voice and video are the use cases QoS exists for. Latency and jitter budgets, DSCP markings, IP phone trust, LLQ configuration, codec bandwidth math, and wireless voice via WMM.

6 min read Apr 25, 2026

QoS public

QoS Queueing, Policing, and Shaping Compared

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LLQ, CBWFQ, policing, and shaping each do something different. The three primitives, when to use which, hierarchical shaping for sub-rate WAN handoffs, and the production patterns.

7 min read Apr 25, 2026

QoS public

QoS Classification, Marking, and Trust Boundaries

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Classification and marking at the trust boundary are the foundation of every QoS deployment. The patterns (untrusted access ports, conditional trust for IP phones, explicit MQC marking) and the discipline that makes them work.

7 min read Apr 25, 2026

QoS public

Cisco MQC (Modular QoS CLI): The Operator's Walkthrough

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The Cisco MQC three-construct model (class-map, policy-map, service-policy) covers every QoS feature on IOS, IOS XE, and IOS XR. The grammar, common actions, hierarchical policies, and verification.

6 min read Apr 25, 2026

QoS public

DSCP and IP Precedence Explained Byte by Byte

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DSCP is the 6-bit Layer 3 marking that drives modern QoS. The byte format, the standardized PHBs (CS, AF, EF), Cisco's DSCP-to-CoS-to-MPLS-EXP mapping, and trust boundary discipline.

6 min read Apr 25, 2026

SD-WAN public

SD-WAN Security and the SASE Convergence

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SD-WAN provides encryption and segmentation but creates an inspection gap. SASE fills that gap with cloud-delivered SWG, CASB, FWaaS, ZTNA, and DLP. The 2026 vendor landscape compared.

6 min read Apr 25, 2026

SD-WAN public

SD-WAN Deployment Models: Hybrid, Internet-Only, and Cloud On-Ramp

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The four SD-WAN branch deployment models compared (hybrid, internet-only, cloud on-ramp, multi-cloud), HQ patterns, and the typical 18-30 month migration from MPLS-only.

6 min read Apr 25, 2026

SD-WAN public

Cisco vManage / SD-WAN Manager: The Operator's Walkthrough

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Cisco vManage (now SD-WAN Manager) is the management plane of Cisco Catalyst SD-WAN. Templates, policies, dashboards, the REST API, HA model, and the operational realities at scale.

5 min read Apr 25, 2026

SD-WAN public

Cisco Catalyst SD-WAN Architecture: vManage, vSmart, vBond, WAN Edge

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The four-component Cisco Catalyst SD-WAN (formerly Viptela) architecture: vManage, vSmart, vBond, and WAN Edge. OMP routing protocol, cEdge vs vEdge, fabric bring-up walkthrough.

6 min read Apr 25, 2026