Category Archives: Cisco
Service-provider core resilience is not the number of redundant routers in a diagram. It is the set of customer services, control planes, and operating functions that remain usable when a defined failure occurs. The current 350-501 SPCOR v1.1 blueprint includes core architectures, routing protocols, MPLS, Segment Routing, traffic engineering, QoS, security, virtualization, and network assurance, […]
Provider QoS troubleshooting is difficult because congestion can appear as packet loss, delay, jitter, reduced throughput, application timeouts, or customer complaints long after the original bottleneck. The current 350-501 SPCOR v1.1 blueprint includes MPLS QoS models, DiffServ/IntServ concepts, trust boundaries, classification, marking, policing, shaping, queuing, and traffic engineering. The practical skill is to identify where […]
Traffic engineering exists because shortest-path routing does not automatically produce the best use of a provider network. The current 350-501 SPCOR v1.1 blueprint includes MPLS traffic engineering, SRTE, QoS models, path computation, policy, and network assurance. The useful mental model is cause and effect: demand enters the network, routing selects available paths, capacity becomes uneven, […]
Segment Routing changes the way a provider expresses a path through the network. Instead of requiring every transit node to maintain per-tunnel signaling state, the ingress can steer traffic through an ordered list of segments that identify nodes, adjacencies, services, or instructions. The current 350-501 SPCOR v1.1 blueprint explicitly includes SR, SRTE, and SRv6, so […]
Layer 2 VPN and EVPN services are valuable because they let a provider carry customer Ethernet semantics across a routed core without turning the entire provider network into one Layer 2 domain. The current 350-501 SPCOR v1.1 blueprint includes L2VPN, EVPN, MPLS, Segment Routing, and service-provider architecture, so the useful design question is not merely […]
MPLS Layer 3 VPN diagrams often show customer edges connected to provider edges, a cloud in the middle, and colored VPNs that appear perfectly isolated. The real control boundary is created by VRFs, route distinguishers, route targets, MP-BGP policy, MPLS forwarding, PE-CE routing, and the operational processes that prevent one customer’s routes from entering another […]
MPLS is easiest to understand when the label is treated as forwarding context rather than as a replacement for IP routing. The current 350-501 SPCOR v1.1 blueprint still includes MPLS, LDP, traffic engineering, VPN services, and related provider-core behavior. Routers use routing information to establish reachability, label-distribution mechanisms advertise label bindings, and the data plane […]
IS-IS is often harder to learn than it is to operate because its terminology feels unfamiliar to engineers who first learned OSPF. In a provider core, however, the useful mental model is simple: IS-IS is a link-state IGP that distributes topology information so routers can calculate shortest paths to infrastructure prefixes and next hops. The […]
BGP in a service-provider network is not simply a protocol for exchanging internet routes. It is a policy system that connects customer reachability, infrastructure, MPLS VPNs, peering, transit, route reflection, traffic engineering, and security. Cisco’s current 350-501 SPCOR exam remains the core requirement for CCNP and CCIE Service Provider, and the current v1.1 blueprint explicitly […]
Modern data centers produce more telemetry than most teams can comfortably interpret: interface counters, routing state, controller faults, flow records, streaming telemetry, logs, APIs, host metrics, storage events, application traces, and automation history. The active 350-601 DCCOR v1.1 blueprint still includes SPAN/ERSPAN, NetFlow, streaming telemetry, monitoring, configuration management, and troubleshooting across network, compute, and storage […]
NX-API and REST automation should be understood as a state-control loop rather than as a way to send commands faster. The active 350-601 DCCOR v1.1 blueprint still includes automation, programmability, REST APIs, Python, Ansible, and data-center controller interactions. The production question is whether automation can read the current state, express the intended state, change only […]
Leaf-spine fabrics are often described as inherently resilient because every leaf can connect to multiple spines and ECMP can use parallel paths. That is a good starting property, not a complete high-availability design. The active 350-601 DCCOR v1.1 blueprint still emphasizes data-center routing, switching, VXLAN EVPN, first-hop behavior, software lifecycle, and monitoring—all of which determine […]
Data-center network security is strongest when the architecture starts with the assets and trust relationships that matter, not with a list of controls. The active 350-601 DCCOR v1.1 blueprint includes management security, authentication/authorization/accounting, ACI security, infrastructure protection, and network/data-center control boundaries. The operational question is which path an attacker or accidental change can use and […]
Cisco UCS makes more sense when it is viewed as a system for composing server identity, connectivity, firmware policy, and lifecycle rather than as a collection of blade and rack hardware. That mental model sits directly inside the active 350-601 DCCOR v1.1 compute domain, which still covers UCS rack servers, blade chassis, infrastructure/network/storage/server policies, software […]
Choosing between Fibre Channel and IP-based storage is not a contest between an old technology and a modern one. It is a decision about latency, loss behavior, operational skill, scale, failure domains, convergence, cost, and what the application expects from block storage. Those trade-offs remain directly relevant to 350-601 DCCOR, whose active v1.1 blueprint still […]
