Virtual Device Context (VDC) With Cisco NX-OS VDC you can divide a physical N7K series switch into multiple logical switches, it will have different management/control and definitely different data planes. By default all ports belong to the default VDC. From default VDC you can create other VDCs and/or jump to them (with command switchto vdc). […]
Double-Sided vPC Dual-sided vPC or Double-side vPC as known as back-to-back vPC or multilayer vPC is combination of multiple vPC layers. In double-sided vPC we have two layers of vPC pairs. Traditionally, our access layer switches are in vPC whose southbound links connect to servers. Their northbound links connect to aggregation layer who are also […]
vPC and STP By default, only vPC primary switch (Verify it using show vpc role) sends and receives BPDUs on the member ports (even if the root bridge is the vPC secondary switch. Verify it yourself by show spanning-tree interface pomember detail | i sent on the secondary switch). Let’s imagine that primary devices goes […]
In this section, let’s see vPC initialization process; then we will discuss on different failure scenarios: The minute you enable vPC feature, the switch sends UDP 3200 ping keepalive to establish connectivity with its peer. Once the connectivity established, the switch in turn enables CFSoE to synchronize the control plane and to carry PDUs for […]
In this topic, we are going to proceed with basic vPC configuration on NX-OS. Let’s review what we would need upfront before the configuration. We would need L3 connectivity for Peer Keepalive. For example, the management interface. We would require to enable vPC and LACP features. LACP must be used on all member interfaces as […]
After covering Port-Channel let’s know talk about virtual Port Channel (vPC). virtual Port Channel allows two NX-OS switches to provide a single port-channel to the downstream devices (Similar to VSS and Stackwise in Catalyst environment). Without vPC, STP blocks one of the ports. In addition, you don’t have high availability. Note that the downstream switch […]
Link Aggregation Port-channel is to NX-OS as EtherChannel is to Catalyst. Juniper calls it Aggregated Ethernet interface while Microsoft refers to NIC Teaming . In fact, all refer to the same concept of grouping couple of ports together in to a single logical interface. Above all, The main advantage of grouping some ports into a […]
STP Features In this section we will discuss on different improvement which added to the Rapid spanning-tree. In particular we talk about: Convergence Optimization Edge Port STP Filters BPDU Filter BPDU Guard Root Guard Unidirectional Link Detection Loop Guard Bridge Assurance Convergence Optimization Spanning-Tree Edge Port This is equivalent of PortFast feature with Common Spanning-Tree. […]
A Brief Introduction to MST IEEE 802.1s originally started as Cisco’s Multiple Instances Spanning Tree Protocol (MISTP). Remember that RapidPVST+ each VLAN is mapped to a single spanning tree instance. When you have 200 VLANs, it means there are 200 instances of spanning tree. This requires a lot of CPU power and memory. You can […]
A Brief Evolution of Spanning-Tree Protocols on NX-OS Before discussing on IEEE 802.1w, I would want to present a brief history of Spanning-tree evolution, the we continue with our main subject of this post. Spanning-tree is the loop prevention mechanism in Layer-2. According to graph theory: Spanning: A spanning graph is a subgraph obtained by […]
Elissa Garlin
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