Networking Security
SD-WAN
Software-defined WAN: central control, path selection and secure branch connectivity.
- 17 notes
- 148 minutes of reading
- What is SD-WAN? Architecture, components and benefitsWhy traditional WANs struggle with cloud applications, what SD-WAN is, its components (edge devices, controller, orchestrator, management), how the overlay uses several transports, and the benefits and limits. 8 min · Intermediate
- SD-WAN path selection, SLAs and application performanceHow SD-WAN identifies applications, measures links with probes, applies SLA policies for latency, jitter and loss, steers or fails over traffic, and uses QoS, forward error correction and packet duplication to protect real-time traffic. 8 min · Advanced
- SD-WAN security, segmentation and SASEHow SD-WAN secures traffic with IPsec tunnels and segmentation, the security needed for local internet breakout, how SASE combines SD-WAN with cloud security services (SWG, CASB, ZTNA, FWaaS), and a migration plan from MPLS. 8 min · Advanced
- SD-WAN vs MPLS vs IPsec VPN: differences, costs and how to chooseA side-by-side comparison of MPLS, traditional router-based IPsec VPNs and SD-WAN: how each works, what they cost, how they handle cloud traffic and outages, and how to decide which mix suits an organisation. 8 min · Intermediate
- SD-WAN deployment models, zero-touch provisioning and choosing a vendorHow SD-WAN is bought and run (do it yourself, co-managed, fully managed and cloud-delivered), how zero-touch provisioning brings a new site online, typical use cases by sector, and what to check when you compare vendors. 9 min · Intermediate
- Monitoring and operating SD-WAN: link health, application SLAs and troubleshootingHow to monitor an SD-WAN day to day: watching underlay links, overlay tunnels, application SLAs and user experience, which metrics and alerts matter, how traditional monitoring tools fit in, and a simple troubleshooting order. 8 min · Intermediate
- Metro Ethernet and Carrier Ethernet services: E-Line, E-LAN and E-TreeWhat Metro Ethernet is, how providers deliver Ethernet across a city or country, the MEF service types (E-Line, E-LAN, E-Tree), port-based versus VLAN-based services, bandwidth profiles and how to connect a router to the service. 8 min · Intermediate
- HDLC and PPP on Cisco serial links: configuration and troubleshootingHow point-to-point serial WAN links work on Cisco routers: DCE and DTE and the clock rate, Cisco HDLC, PPP with LCP and NCPs, PAP and CHAP authentication, and the show and debug commands that find faults. 8 min · Beginner
- GRE tunnels on Cisco IOS: configuration, MTU and common problemsHow Generic Routing Encapsulation (GRE) builds virtual point-to-point links over another network, how to configure a GRE tunnel on Cisco IOS, why MTU and MSS matter, how to avoid recursive routing, and why GRE is combined with IPsec. 9 min · Intermediate
- Frame Relay (legacy WAN): DLCIs, LMI, point-to-point and multipointA concise guide to Frame Relay, the legacy packet-switched WAN: virtual circuits, DLCIs, LMI and Inverse ARP, the provider switch, point-to-point and multipoint sub-interfaces, split horizon problems, and what replaced it. 9 min · Intermediate
- Advanced PPP: multilink, fragmentation and interleaving, PPPoA and PPPoEHow PPP grew beyond single serial links: Multilink PPP to bundle links, link fragmentation and interleaving for voice, PPP over ATM for older DSL, and PPPoE, still used by many broadband providers, with Cisco IOS client and server examples. 10 min · Intermediate
- Performance Routing (PfR) and OER: legacy intelligent path controlA concise guide to Cisco Optimized Edge Routing (OER) and Performance Routing (PfR): master controllers and border routers, the five phases, policies and variance, timers for labs, and how SD-WAN application-aware routing replaced them. 8 min · Advanced
- Cellular WAN: from legacy 3G to 4G and 5G backup linksHow routers use mobile networks as a WAN link: what 3G wireless WAN was and why it is legacy, how a modern 4G or 5G interface is set up with an APN, and how to make it a reliable backup with floating static routes and IP SLA tracking. 8 min · Intermediate
- Cisco Catalyst SD-WAN architecture: Manager, Controller, Validator, OMP and TLOCsHow Cisco Catalyst SD-WAN (formerly Viptela) is built: the Manager, Controller and Validator roles and their old names, WAN edge routers, control connections, OMP, TLOCs and colours, system IP and site ID, and how the data plane tunnels form. 10 min · Advanced
- Cisco SD-WAN lab, onboarding and templates: from controllers to configured edgesHow to build a Cisco Catalyst SD-WAN lab, install the controllers, register devices through Plug and Play Connect, onboard vEdge and cEdge routers, and configure them with device templates, feature templates, CLI templates and configuration groups. 10 min · Advanced
- Cisco SD-WAN service VPNs, OSPF and BGP at the siteHow Cisco SD-WAN separates traffic with VPN 0, VPN 512 and service VPNs, how service VPNs map to VRFs on IOS XE edges, and how OSPF and BGP connect site LANs and data centres to the overlay through redistribution with OMP. 9 min · Advanced
- Cisco SD-WAN policies: localised, centralised, hub-and-spoke and application-aware routingHow Cisco SD-WAN policies work: localised policies on the edge (QoS, ACLs, policers, route policies for BGP and OSPF) and centralised policies on the Controller (control policies that build topologies such as hub-and-spoke, data policies and application-aware routing with SLA classes). 10 min · Advanced