Segment Routing (SR-MPLS): Replacing LDP and RSVP-TE
SR-MPLS keeps the MPLS data plane and drops LDP and RSVP-TE. Prefix-SIDs, adjacency-SIDs, source-routed label stacks, SR-MPLS vs SRv6, and why networks migrate.
Archive
Latest posts — page 44
VTP (VLAN Trunking Protocol): v1, v2, v3 and Why It's Dangerous
How VTP propagates VLANs across a domain, the three modes, the revision-number disaster, v1/v2/v3 differences, and why many engineers disable it.
OSPF Passive Interface: What It Does and Where to Use It
OSPF passive-interface stops Hellos and adjacencies on an interface but still advertises its subnet. Config, the default pattern, and the route-filter gotcha.
EIGRP Neighbor Requirements: The 5 Things That Must Match
The 5 things that must match for EIGRP routers to become neighbors: subnet, AS number, K-values, authentication, and process membership. Plus what does NOT need to match.
HSRP States: The 6-State Machine with show standby Output
All 6 HSRP states (Initial, Learn, Listen, Speak, Standby, Active), what drives the election, why preempt matters, interface tracking, and real show standby output.
VLAN vs VXLAN: The L2 Overlay, Demystified
VLAN vs VXLAN explained: a VLAN tags L2 segments, VXLAN encapsulates them across L3. The 4,094 limit, VTEPs, BGP EVPN, and when you actually need VXLAN.
Cisco Catalyst SD-WAN: The Rebrand, the Architecture, OMP
Cisco Catalyst SD-WAN (formerly Viptela / Cisco SD-WAN): the naming history, the four-plane architecture, OMP routing, and the zero-touch edge onboarding flow.
How to Install Cisco CML 2.10 on VMware ESXi (Step-by-Step with Screenshots)
A step-by-step, screenshot-by-screenshot walkthrough of installing Cisco Modeling Labs (CML) 2.10 on VMware ESXi: deploy the OVA, size the VM, attach the refplat ISO, run setup, and start your first node.
QoS on a Router: A Practical Cisco IOS XE Walkthrough
How to build a working QoS policy on a Cisco router: MQC class maps, policy maps, the LLQ + CBWFQ model, and the shaper rule that makes it actually engage.
BGP Weight: The Cisco-Only Path Attribute (and When to Use It)
BGP weight is the first tiebreaker in the path-selection algorithm, set locally and never propagated. The three ways to set it, how it compares to LOCAL_PREF, and worked examples.
QoS for VoIP Across an MPLS WAN
End-to-end QoS for VoIP across an MPLS L3VPN: DSCP marking, the LLQ + CBWFQ policy at the CE edge, and the DSCP-to-MPLS-EXP mapping the carrier needs.
STP and EtherChannel: When They Collide and Who Wins
How EtherChannel hides bundled links from STP, the bundling protocols (LACP, PAgP, on), the dangerous failure modes, and why LACP active on both sides is the only safe configuration.