Network Topology Design

This network design features a dual-infrastructure setup using two different firewall platforms, FortiGate and Palo Alto, to provide redundancy and segmentation. The design aims to ensure high availability and robust security for a network with critical assets, likely belonging to a mid to large-sized enterprise. The network is connected to two Internet Service Providers (ISPs) labeled ISP-A and ISP-B. The connections are managed through two switches (SW-15 and SW-16) on the FortiGate side, and two other switches (SW-19 and SW-110) on the Palo Alto side. These switches act as the primary and backup points of entry for the internet traffic, ensuring that if one ISP fails, the other can still provide connectivity. This setup provides resilience and fault tolerance. On the FortiGate side, two FortiGate firewalls are deployed in a high-availability (HA) configuration. This setup means that one firewall will take over if the other fails, providing uninterrupted security services. The firewalls are connected to layer 3 switches (L3-SW7 and L3-SW13) which manage internal routing and distribution of traffic. The layer 2 switches (L2-SW13) underneath connect to end devices or servers, shown as VPCs. This segmentation allows the internal network to be divided into different VLANs (VLAN 10, 21, 22, 23), each with its IP subnet, offering isolation and traffic management according to the organization’s requirements. Similarly, on the Palo Alto side, there are two firewalls, also configured in HA. They are connected to a layer 3 switch (L3-SW8) that performs a similar role in routing and distributing traffic. VLANs (30, 31, 32, 33) are used here as well, indicating that the network is segmented based on functions or departments. This helps in controlling and securing traffic flows, as well as in implementing policies such as access control lists (ACLs) or quality of service (QoS). The purpose of this design is twofold: to provide high availability and to ensure security and segmentation across the enterprise network. By using two different firewall platforms, the design can leverage the strengths of each while maintaining a diverse security posture, which is often recommended to avoid single points of failure or uniform vulnerabilities. The VLAN segmentation helps in managing and isolating traffic, ensuring that security policies can be applied more granularly. Additionally, the HA configurations on both the FortiGate and Palo Alto sides prevent downtime during hardware failures, contributing to the network's resilience. This setup offers a scalable, secure, and resilient architecture capable of supporting a range of enterprise applications and services while maintaining strict security controls and high availability.

An organized network structure in a data center is critical for performance, security, scalability, and ease of management. Below is a best-practice, real-world approach used in modern enterprise and data-center environments. --- 1️⃣ Core Design Principle – Layered Architecture A well-organized data center network follows a hierarchical (tiered) design. 🔹 A. Core Layer (Backbone) Purpose: High-speed data forwarding between major network segments Characteristics: High-capacity switches (40G / 100G / 400G) Redundant core switches (Active-Active) No access policies (pure routing) Low latency & high throughput Connects to: Internet routers DR site / WAN Data center edge firewalls --- 🔹 B. Aggregation / Distribution Layer Purpose: Policy enforcement and traffic control Functions: VLAN routing (Inter-VLAN) ACLs & QoS Load balancing Firewall integration Connects: Core layer Access layer switches Security appliances (FW, IPS) --- 🔹 C. Access Layer Purpose: Device connectivity Connected devices: Servers Storage (SAN / NAS) NVRs, CCTV servers Biometric / Access control systems Features: 1G / 10G / 25G ports PoE where required Port security & VLAN tagging --- 2️⃣ Physical Network Organization 🔹 Rack-wise Design Separate racks for: Network (Core, Agg switches) Compute (Servers) Storage (SAN / NAS) Top-of-Rack (ToR) switches for each server rack Structured cabling (fiber + Cat6A) 🔹 Cable Management Color-coded cables 🔵 Management 🟡 Storage 🔴 Production Fiber for uplinks, copper for short runs Proper labeling (both ends) --- 3️⃣ Logical Network Segmentation (Very Important) 🔹 VLAN & Subnet Separation Network Type Example VLAN Server Network VLAN 10 Storage Network VLAN 20 Management (iDRAC, iLO) VLAN 30 CCTV / IoT VLAN 40 User / Admin Access VLAN 50 Benefits: Better security Broadcast control Easy troubleshooting --- 4️⃣ Redundancy & High Availability 🔹 Network Redundancy Dual core switches Dual uplinks from access → aggregation LACP / Port-channel Spanning Tree (RSTP / MSTP) 🔹 Power Redundancy Dual power supplies Separate PDUs UPS + Generator backed --- 5️⃣ Security Layer Integration 🔹 Perimeter Security Edge firewall (HA mode) IDS / IPS DDoS protection 🔹 Internal Security Micro-segmentation East-West traffic firewalling Zero-Trust model (recommended) --- 6️⃣ Storage & High-Speed Traffic Design Dedicated Storage VLAN / Fabric iSCSI / FC / NVMe-oF separation Jumbo frames (if supported) No routing between storage & user networks --- 7️⃣ Monitoring & Management 🔹 Network Monitoring SNMP / NetFlow NMS tools (SolarWinds, PRTG, Zabbix) Syslog servers

Leaf-Spine Network Topology is one of the most underrated network topologies that powers the most expensive AI and HPC GPU datacenters in the world. You want 500K+ GPUs, stitch it together with hierarchical switching — the leaf switches, spine, super spine, and core groups for the GPU compute nodes and storage nodes for GPUDirect Storage RDMA from VRAM straight over your storage fabric. It has a dent on the performance of distributed MoE model inferencing if not collocating experts on near ranks under the same leaf switches or spine, and having to traverse a distant spine or a detached leaf has a significant impact on TPS/GPU throughput and latency. Switch topology also matters to NCCL collective efficiency, AllToAll collectives for expert dispatch and combine token routing communication latency among experts for MoE models, RDMA behaviour across nodes for token transfer over RDMA with NIXL in a P/D disaggregated inferencing. SemiAnalysis InferenceX v2 data makes this concrete — EP (Expert Parallel) AllToAll staying within NVLink (72 GPUs on NVL72) vs crossing the IB fabric is one of the biggest throughput levers between GB200 NVL72 and B200 at the same interactivity target. Network topology isn't background plumbing. It's on the critical path. And selecting the right switch for the right workload profile also matters a lot in non-NVL72 clusters — InfiniBand Quantum NDR or later XDR for compute node leaf switches or Spectrum-X Ethernet switches — at good aggregate link speed matters more, and more importantly the cabling between switches: optical fibre? Leaf-Spine Network Topology is one of the most important topics I have been going deep on lately — and BGP routing (did more of this at Equinix) between backend network switches cross-node routing traffic straight from GPU nodes VRAM to Storage nodes. #GPUInfrastructure #DistributedInference #NetworkEngineering #AIInfrastructure #HPC

Structured cabling is no longer passive. It’s programmable infrastructure... ...engineered for determinism, not just connectivity. 𝗙𝗿𝗼𝗺 $𝟭𝟰𝗕 𝗶𝗻 𝟮𝟬𝟮𝟰 𝘁𝗼 $𝟮𝟭.𝟲𝟵𝗕 𝗯𝘆 𝟮𝟬𝟮𝟵, ...driven by 400 Gbps fabrics, Wi-Fi 7, and edge compute... ...and none of it tolerates signal degradation, crosstalk, or choke points. If you're building for high-bandwidth throughput, tight thermal margins, and zero-touch ops- anchor your spec to Corning Incorporated. 1. 𝗘𝗻𝗴𝗶𝗻𝗲𝗲𝗿 𝗻𝗼𝘁 𝗷𝘂𝘀𝘁 𝗹𝗮𝘆 𝗰𝗮𝗯𝗹𝗲.  Decommission legacy copper Cat5e/6 and OM1/OM2 fibre.  Standardise to Corning OM4/OM5 multimode for ≤150m links.  Use Corning single-mode trunks where low loss over distance is critical.  For <30m links running 25/40 Gbps...  ...use Everon® Cat. 8.1 jacks Class I ISO/IEC 11801, rated for 2 GHz operation.    2. 𝗗𝗲𝘀𝗶𝗴𝗻 𝗳𝗼𝗿 𝗺𝗼𝗱𝘂𝗹𝗮𝗿𝗶𝘁𝘆 𝗮𝗻𝗱 𝗿𝗲𝗽𝗲𝗮𝘁𝗮𝗯𝗶𝗹𝗶𝘁𝘆.  Manual terminations = variability.  Corning EDGE™ and EDGE8™ platforms deliver:   • MPO trunks factory-tested to IEC 61300-3-34   • Polarity-aligned connector schemas   • Zero field polishing, minimal insertion loss  This yields deterministic link budgets from day zero.    3. 𝗢𝗽𝘁𝗶𝗺𝗶𝘀𝗲 𝗳𝗼𝗿 𝗥𝗨 𝗱𝗲𝗻𝘀𝗶𝘁𝘆.  Stage front-access patches separately from rear trunk ingress to prevent cable crossovers.  Design rear trays to isolate thermals from active equipment exhaust zones.  Target 48 ports/RU with low-loss MTP cassettes and angled patch panels.  Maintain 30 mm bend radius backed by Corning ClearCurve® fibre    4. 𝗠𝗮𝗸𝗲 𝘁𝗼𝗽𝗼𝗹𝗼𝗴𝘆 𝗱𝗶𝘀𝗰𝗼𝘃𝗲𝗿𝗮𝗯𝗹𝗲 𝗮𝗻𝗱 𝗮𝘂𝗱𝗶𝘁𝗮𝗯𝗹𝗲.  Use Corning ClearTrack™ for link-level RFID/barcode tagging.  Ingest cable metadata into DCIM or NetBox.  Tie port IDs to MACs, serials, and circuit IDs.  Build a live, queryable physical twin...  ...enabling cable trace in seconds, not site visits.    5. 𝗖𝗲𝗿𝘁𝗶𝗳𝘆 𝗳𝗼𝗿 𝗦𝘂𝗿𝗲.  Use Fluke DSX-8000 for full-link testing...  ...length, attenuation, reflectance, and return loss.  Enforce IEC 61300-3-35 inspection before mating.  Validate end-to-end compliance with IEEE 802.3bs (100/200/400G).  Train field techs on airflow-aware routing, minimum bend radius, and physical strain relief best practices.    This is structured cabling reimagined as a data-driven subsystem. Because at 400 Gbps, you don’t get retries... ...you get signal or you don’t. Corning brings an integrated ecosystem... ...fibre, connectors, pre-termination, tagging, certification... ...to make physical layer performance predictable. Tell me - Which myth is still holding back your cabling refresh? 𝗣.𝗦. 𝗦𝗮𝘃𝗲 + 𝘀𝗵𝗮𝗿𝗲 𝘄𝗶𝘁𝗵 𝘆𝗼𝘂𝗿 𝗶𝗻𝗳𝗿𝗮 𝘁𝗲𝗮𝗺.

Last week, during a design discussion, someone asked me a question I hear a lot: “𝗢𝗻 𝗮𝗻 𝗜𝗘𝗖 𝟲𝟭𝟴𝟱𝟬 𝗽𝗿𝗼𝗰𝗲𝘀𝘀 𝗯𝘂𝘀... 𝘄𝗵𝗲𝗻 𝗱𝗼 𝘆𝗼𝘂 𝗰𝗵𝗼𝗼𝘀𝗲 𝗣𝗥𝗣 𝘃𝘀 𝗛𝗦𝗥? 𝗔𝗻𝗱 𝘄𝗵𝘆 𝗶𝘀 𝗲𝘃𝗲𝗿𝘆𝗼𝗻𝗲 𝘀𝗼 𝘀𝘁𝗿𝗶𝗰𝘁 𝗮𝗯𝗼𝘂𝘁 𝗣𝗧𝗣?” That question stuck with me, because it highlights something important: 𝗜𝗻 𝗮 𝗱𝗶𝗴𝗶𝘁𝗮𝗹 𝘀𝘂𝗯𝘀𝘁𝗮𝘁𝗶𝗼𝗻, 𝘁𝗵𝗲 𝗻𝗲𝘁𝘄𝗼𝗿𝗸 𝗶𝘀 𝗽𝗮𝗿𝘁 𝗼𝗳 𝘁𝗵𝗲 𝗽𝗿𝗼𝘁𝗲𝗰𝘁𝗶𝗼𝗻 𝗮𝗻𝗱 𝗰𝗼𝗻𝘁𝗿𝗼𝗹 𝘀𝘆𝘀𝘁𝗲𝗺. So “almost reliable” isn’t a thing. We engineer for 𝘇𝗲𝗿𝗼-𝗹𝗼𝘀𝘀 𝗮𝗻𝗱 𝘇𝗲𝗿𝗼-𝗿𝗲𝗰𝗼𝘃𝗲𝗿𝘆 𝘁𝗶𝗺𝗲. Here’s the simplest way to look at it: 𝟭. 𝗣𝗥𝗣 𝘃𝘀 𝗛𝗦𝗥 𝗶𝘀 𝗮𝗯𝗼𝘂𝘁 𝙝𝙤𝙬 𝙮𝙤𝙪 𝙨𝙪𝙧𝙫𝙞𝙫𝙚 𝙖 𝙛𝙖𝙞𝙡𝙪𝙧𝙚 🛣️ 𝗣𝗥𝗣 = 𝘁𝘄𝗼 𝘀𝗲𝗽𝗮𝗿𝗮𝘁𝗲 𝗵𝗶𝗴𝗵𝘄𝗮𝘆𝘀 You send the same packet on two independent networks (LAN A and LAN B). If one network fails, the other keeps delivering — 𝗻𝗼 𝘀𝘄𝗶𝘁𝗰𝗵𝗼𝘃𝗲𝗿 𝗱𝗲𝗹𝗮𝘆. 🔀 𝗛𝗦𝗥 = 𝘁𝘄𝗼-𝘄𝗮𝘆 𝗽𝗮𝘁𝗵 𝗶𝗻 𝗮 𝗹𝗼𝗼𝗽 𝘁𝗼𝗽𝗼𝗹𝗼𝗴𝘆 You send packets both ways around the topology. If one link fails, traffic still reaches the destination via the other direction — 𝘀𝗲𝗮𝗺𝗹𝗲𝘀𝘀𝗹𝘆. 𝟮. 𝗣𝗧𝗣 𝗶𝘀 𝗮𝗯𝗼𝘂𝘁 𝗺𝗮𝗸𝗶𝗻𝗴 𝘁𝗵𝗲 𝗱𝗮𝘁𝗮 𝗺𝗲𝗮𝗻𝗶𝗻𝗴𝗳𝘂𝗹 ⏱️ Even if packets arrive, measurements must be aligned in time. 𝗣𝗧𝗣 𝗽𝗿𝗼𝘃𝗶𝗱𝗲𝘀 𝘁𝗵𝗲 𝗽𝗿𝗲𝗰𝗶𝘀𝗲 𝘁𝗶𝗺𝗲 𝘀𝘆𝗻𝗰 needed for accurate sampling, time-stamping, and deterministic behavior at the process level. 𝟯. 𝗥𝗲𝗮𝗹 𝘀𝘂𝗯𝘀𝘁𝗮𝘁𝗶𝗼𝗻𝘀 𝗮𝗿𝗲 𝗺𝗶𝘅𝗲𝗱, 𝗻𝗼𝘁 𝗽𝗲𝗿𝗳𝗲𝗰𝘁 Not every device supports redundancy natively:  • 𝗗𝗔𝗡 (dual attached) supports redundant connectivity  • 𝗦𝗔𝗡 (single attached) has only one interface  • 𝗥𝗲𝗱𝗕𝗼𝘅 brings SAN devices into PRP/HSR by making them appear like a virtual DAN That’s why, in practice, you often see 𝗵𝘆𝗯𝗿𝗶𝗱 𝗱𝗲𝘀𝗶𝗴𝗻𝘀 (PRP backbone + HSR loops) to balance availability, topology, and retrofit constraints. 📌 I’ve shared a quick carousel that summarizes this visually. #IEC61850 #DigitalSubstation #PRP #HSR #SubstationAutomation #IEC62443 #Networksecurity

I often watched teams spend months debating which router, firewall, or vendor to choose - only to end up with a network that still behaved unpredictably under load. Modern enterprise networking problems aren’t hardware problems. They’re system design problems. This guide breaks down the Modern Enterprise Networking Stack the way it actually works in production - not as a list of devices, but as a set of behaviors and responsibilities that together define 100% of network outcomes. - At the foundation is Topology Design (30%). Leaf-spine, Clos fabrics, edge aggregation, and multi-region layouts determine blast radius, scalability, and failure isolation long before traffic ever flows. - Next is Traffic Behavior (25%). Path selection, latency variance, failover timing, and load balancing decide whether applications feel fast, slow, or randomly broken - even when links are technically “up.” - Then comes the Control Plane (20%). BGP architecture, policy distribution, route convergence, and segmentation control how the network reacts to change. This is where stability is either engineered or lost. - Finally, Security & Governance (25%) isn’t an add-on. Zero trust, microsegmentation, data sovereignty, and audit trails define whether the network can safely support modern workloads, regulations, and distributed teams. The key insight is this: You don’t get reliability by optimizing one layer. You get it by balancing all of them. Most failures I’ve seen weren’t caused by a bad box or a missing feature. They came from overweighting topology, ignoring traffic behavior, under-designing the control plane, or bolting on security too late. This is the mental shift architects have to make: Stop thinking in percentages of hardware. Start thinking in percentages of system responsibility. Because in modern enterprises, the network isn’t a collection of components - it’s a distributed system, and every layer contributes to the outcome.

Architecture is not a branding term. It is a structural commitment that will define feeder density, optical margin, upgrade exposure, and capital strategy for the next thirty years. Centralized. Distributed. Cascade. TAP. Active Ethernet. These are not interchangeable labels. Each model imposes measurable consequences on corridor geometry, conduit diameter, splice environments, and long-term scalability. A 1:32 split is not just a ratio. It is 15 to 17 dB of structural reality. Cascade staging is not just flexibility. It is compounded insertion loss sensitivity. Active Ethernet is not just “dedicated fiber.” It is powered field dependency and operational cost exposure. When architecture is selected without integrating routing constraints, optical physics, feeder density modeling, and take rate projections, the outcome is predictable: • Optical margin exhaustion • Feeder congestion • Enclosure proliferation • Reconstruction disguised as “upgrade” Architecture cannot be evaluated independently from corridor geometry. If routing hierarchy constrains conduit diameter, it constrains architectural feasibility. If feeder density is mis-modeled, lifecycle sustainability erodes quietly. Architectural Selection and Structural Consequences challenges the industry habit of choosing topology first and modeling consequences later. If architecture defines optical margin, feeder density, and upgrade potential for decades, what quantitative discipline must govern feeder sizing before construction begins? #TelecomEngineeringDoneRight; #FTTH; #PONDesign; #NetworkArchitecture; #FiberEngineering; #OSPEngineering; #BroadbandInfrastructure; #OpticalBudget; #FeederDensity; #EngineeringDiscipline

🔧 Enterprise Network Infrastructure Design – Ready for Implementation I'm excited to share a detailed topology design for a highly available, multi-area enterprise network that I have carefully planned and will be implementing soon. This project combines core network segmentation, efficient routing protocols, security zoning, and city-wide distribution — all structured for performance, scalability, and reliability. 🌐 Project Overview This infrastructure supports two major enterprise areas (Area 1 & Area 2), each with its own LAN and DMZ zones, interlinked through a Backbone Area 0 using OSPF routing protocol, and extended further to city clusters via RIP v2 redistribution. 🔻 Key elements included in this design: ✔DMZ Zones for hosting servers (Web, Email, DNS, SQL, Storage) securely separated from the internal LAN. ✔LAN Segments for internal users, printers, VoIP phones, and city offices. ✔Firewall Integration at all major ingress/egress points. ✔Zone-A and Zone-B connecting 6 remote cities via dedicated routers and Core sites. ✔Multiple Clouds and Cellular Backup solutions. 🔻Routing Protocols: ✔OSPF: Backbone and Area connections ✔RIP v2: Used in city-wide and rural-area links ✔Redistribution between protocols ensures seamless communication. 🧩 Technical Highlights ✅ VLAN segmentation for traffic control ✅ Server roles distributed in DMZ for scalability ✅ Dual-layer firewall architecture for security ✅ Dynamic routing via OSPF and RIP with redistribution at the core ✅ Cloud and cellular integration for redundancy ✅ IP schema and subnetting well-documented ✅ Suitable for enterprise, governmental, or multi-branch organizations 📌 Current Status ✅ Design Phase: Completed 🚀 Implementation: Starting Soon 💬 Feedback & Collaboration If you're a network professional or enthusiast, feel free to share your thoughts or suggestions on the design. 📩 Drop a comment below if you spot any area that could be improved or optimized before deployment. Your input is valuable! 🔹Telegram https://lnkd.in/djw9emVb 🔁 #Networking #OSPF #EnterpriseNetwork #NetworkDesign #Infrastructure #Cisco #RIPv2 #Routing #Firewall #GNS3

High Availability Network Design - A Lab-Based Implementation   Maintaining seamless connection in enterprise networks is more than only strong hardware -- it is about redundancy and smart architecture. "Hardening Network Security" by Abi Adrian, an intensive lab-packed study on how to set up and verify a robust network with FortiGate, Cisco, MikroTik devices.   Among the lab’s key findings:   Static and Dynamic OSPF Routing Configurations Link Aggregation (EtherChannel) for bandwidth and redundancy requirements Realistic failure simulation (ISP, switch, firewall) and transparent failover behavior Active-passive Internet and dual-firewall architecture,Dual firewall Complete scripts for Mikrotik, FortiGate and Cisco switches/routers   The result? A reliable topology that tolerates outages and retires nodes smoothly without affecting users—this allows to make a statement that the design fulfills its defined HA goals.   This is a good book for engineers designing lab and production netoworks that require real world resiliency.   Authored by: Abi Adrian   What part of your network would get the most use out of a setup like this? Let’s discuss!   #HighAvailability #NetworkDesign #FortiGate #Cisco #MikroTik #OSPF #LinkAggregation #Redundancy #NetworkLab #smenode #smenodelabs #smenodeacademy

Office Network Infrastructure Overview This diagram illustrates a typical enterprise network architecture following hierarchical design principles: 🔹 Internet Gateway Layer: Edge router provides WAN connectivity with integrated firewall security 🔹 Core Layer: High-performance core switch serves as the network backbone, enabling fast switching between distribution segments 🔹 Distribution Layer: Distribution switches aggregate access layer traffic and implement network policies 🔹 Access Layer: Access switches provide direct connectivity to end devices including workstations, IP phones, servers, and printers Key Features: Redundant distribution switches for high availability Segmented design for improved performance and security Voice over IP (VoIP) integration with dedicated IP phones Centralized server resources Print services accessible across the network This three-tier hierarchical model ensures scalability, redundancy, and efficient traffic flow while maintaining security boundaries through the integrated firewall at the network perimeter. #NetworkArchitecture #ITInfrastructure #EnterpriseNetworking #CiscoNetworking #NetworkDesign #ITSecurityRetryClaude