Networking Security
Transport Network Design
Designing LAN and WAN transport: design methods, VLANs, redundancy, routing, ACLs, WAN links, QoS, monitoring and troubleshooting.
- 20 notes
- 175 minutes of reading
- Network design fundamentals: building blocks, network types and the design planWhat a network needs (end devices, intermediary devices, protocols and media), how networks are classified by size, topology and where resources live, physical versus logical topology, and why every network starts with a design plan. 7 min · Beginner
- Choosing switches and routers, and configuring them for the first timeThe kinds of switch and router you can buy and how to choose between them, how to reach a device (console, SSH, AUX), the Cisco IOS command modes, and a secure first-time configuration. 8 min · Beginner
- Network design overview: goals, the hierarchical model and design methodologyWhy modern networks must be designed, the four fundamental design goals, the five steps to building a good network, the three-layer and two-layer hierarchical models, modular enterprise architecture and the design methodology. 9 min · Intermediate
- VLANs, trunking, VTP and inter-VLAN routingCollision and broadcast domains, how VLANs split a switched network into separate logical networks, 802.1Q trunking, VTP modes and its risks, access and trunk ports, and the three ways to route between VLANs. 9 min · Intermediate
- Layer 2 redundancy: spanning tree and EtherChannelWhy redundant switch links create Layer 2 loops, how spanning tree elects a root bridge and assigns port roles, how STP, RSTP, MST, PVST+ and Rapid PVST+ compare, and how LACP, PAgP and static EtherChannel bundle links. 10 min · Intermediate
- Routing operations: static routing and dynamic routing protocols comparedHow routers choose paths, static versus dynamic routing, the families of routing protocols (distance vector, link state, advanced distance vector, path vector), RIP, OSPF, IS-IS, EIGRP and BGP, and administrative distance. 10 min · Intermediate
- Layer 3 redundancy: HSRP, VRRP and GLBPWhy the default gateway is a single point of failure, and how first hop redundancy protocols (HSRP, VRRP and GLBP) share a virtual gateway between routers: roles, elections, preemption, states and configuration. 9 min · Intermediate
- Access control lists: purpose, types, placement and best practiceWhat access control lists do and why they are used, standard, extended and named ACLs, how routers process them, inbound versus outbound, where to place each type, and practical guidelines. 9 min · Intermediate
- Network monitoring and management: syslog, NTP, SNMP and controllersWhat network monitoring is and why it matters, a step-by-step approach, syslog message fields, facilities and severity levels, NTP and stratum, SNMP managers, agents and MIBs, and centralised network controllers. 9 min · Intermediate
- WAN technologies: leased lines, PPP, MPLS, Metro Ethernet, broadband and VPNsHow organisations connect sites over long distances: private and public WANs, leased lines and PPP with PAP and CHAP, legacy Frame Relay, MPLS, Metro Ethernet, broadband and mobile, internet VPNs, and how to choose. 9 min · Intermediate
- Quality of service (QoS) for voice, video and business applicationsWhy converged networks need QoS, what voice and video require, classification and DSCP marking, trust boundaries, queuing with LLQ, policing versus shaping, congestion avoidance, and a sample policy. 9 min · Advanced
- Troubleshooting LAN and WAN networks: methods, tools and common faultsA structured troubleshooting process, the top-down, bottom-up, divide-and-conquer and follow-the-path methods, the main tools and commands, and the common LAN and WAN faults with their likely causes. 9 min · Intermediate
- Data centre risks, replication and secure transport (TLS, SSH, Tor, MPLS)The risks a data centre faces, how replica data centres keep services running, and the protocols that protect data in transit: SSL/TLS, SSH and Tor, plus how MPLS carries traffic across provider networks. 8 min · Intermediate
- QoS fundamentals: delay, jitter, loss, the bandwidth-delay product and the three QoS modelsWhat quality of service really controls, the four kinds of delay, jitter and packet loss, how to calculate the bandwidth-delay product, and how best effort, IntServ with RSVP and DiffServ compare. 8 min · Intermediate
- IP Precedence and DSCP values: CS, AF and EF classes and how to decode themHow the ToS byte evolved from IP Precedence to DSCP and ECN, how class selector, assured forwarding and expedited forwarding values are built, how to convert between decimal, binary and ToS values, and common marking choices. 8 min · Intermediate
- QoS classification and marking on Cisco IOS: class maps, NBAR and set commandsHow to classify traffic with class maps using ACLs, DSCP, CoS and NBAR application recognition, how to mark it with set commands in a policy map, where to apply the policy, how QoS pre-classify works on tunnels, and how to verify the result. 9 min · Intermediate
- QoS on LAN switches: trust boundaries, CoS-DSCP mapping and egress queuesWhy switches need QoS even on fast links, where to place the trust boundary, how conditional trust works with IP phones, how switches map CoS and DSCP, and how egress queues are configured on legacy Catalyst MLS QoS and modern Catalyst 9000 switches. 8 min · Intermediate
- Congestion management: CBWFQ, LLQ, bandwidth remaining and hierarchical policiesHow class-based weighted fair queuing guarantees bandwidth, how low latency queuing adds a policed priority queue, why priority queues used to starve other traffic, the difference between bandwidth and bandwidth remaining, and why sub-interfaces need a parent shaper. 9 min · Advanced
- Traffic shaping and policing: CIR, Bc, Be, token buckets and Cisco IOS configurationHow shapers and policers use token buckets, what CIR, Bc, Be and Tc mean, average versus peak shaping, single-rate and two-rate policers with conform, exceed and violate actions, and the legacy Frame Relay traffic shaping you may still read about. 9 min · Advanced
- Congestion avoidance and other QoS tools: WRED, ECN, link fragmentation, RSVP and IP SLA testingHow tail drop causes TCP global synchronisation, how RED and WRED avoid it, where ECN fits, and other QoS tools: legacy multilink PPP fragmentation and interleaving, RSVP admission control, and IP SLA operations to measure delay and jitter. 9 min · Advanced