Top 20 Cisco Nexus Interview Questions and Answers (2024)
Network Engineer who wishes to build a network that unites the Data Center and Cloud must have knowledge of Cisco Nexus switches and since you are here, If your answer to these questions is “Yes”. Then, you are at the right place. We have a list of the top most asked Cisco Nexus interview questions and answers that are the interviewer’s favourite. These questions are selected by some of the geniuses in the networking field in collaboration with recruiters to help all network engineers. Go through these Cisco Nexus interview questions and answers for better interview preparation. Cisco Nexus switches are high-performance, scalable data center switches designed to meet the demanding requirements of modern IT environments. They are like powerful computers that lets big enterprises connect lot of devices at a single place. Some of the features offered by Cisco Nexus Switches are: Let’s move on to see the most asked Cisco Nexus Interview Questions and Answers. Due to popular demands, we at PyNet Labs have decided to separate these questions into two groups – It is of utmost importance to master both these technologies to top any Interview related to Nexus. Let’s get started. Here are the top 10 most asked Nexus vPC Interview Questions: Virtual Port-Channel (vPC) is a multi-chassis port channel in a feature in Cisco Nexus Switches with which we can logically bundle the links of two different chassis. It is similar to VSS, but the main difference is that vPC logically bundles the links. In contrast, VSS creates a single logical switch with one logical control plane for management and configuration. We need to configure and manage VPC on both switches independently. Benefits of vPC: The main components of vPC are as follows: Two Nexus switches and one or more linked devices make up the vPC topology. Peers are the two switches, and everything that supports port channels or LAGs can be the connected device. Among them are servers, switches, firewalls, and other devices. This is a layer two link (Port-Channel) with a minimum 10G capacity for connecting vPC Peer Switches, carrying ARP traffic, BPDUs, HSRPs and sharing mac-addresses traffic to vPC Peers. Between peer switches, the peer-link exchanges state data and carry control traffic. This connection creates a fictitious Control Plane between the two switches, giving the impression that there is just one logical switch. This layer-3 link, which must be at least 1G in speed, is segregated from other traffic by being in a different VRF. This is crucial because some failures could cause either switch to believe that a peer is down while, in reality, it is not. In a split-brain or dual-active situation, both switches believe they are the dominant switch. This issue is avoided by the keepalive link’s heartbeats. Even when there is a failure, both peers can still see one another. Servers and other devices connect to member ports on vPCs. For this to happen, the linked device must set up its port-channel. On both switches, the configuration is the same. While different port numbers are permitted, speed and duplex must be compatible. Although it is best to practice to maintain consistency, the vPC and port-channel numbers do not need to match. Orphan ports are the ports that are not configured as vPC even though they carry a vPC VLAN. We must avoid these ports by always having Dual Attached VPC connections. This includes any hardware that only has a single VPC switch connection. If VPC Peer-Link goes down, Orphan ports will have no way to route the traffic. “Show vpc orphan-ports” is the command to check the orphan ports. We should have the command “feature vpc” enabled. Similarly, we need to have features enabled for other functions, e.g. for LACP or Interface-VLAN. Yes, vPC is a technology used to provide redundancy and load balancing to multiple switches. It operates at level 2, while the routing protocols work on the level 3. While, vPC and routing protocols operate at different levels, they still interact to provide a scalable and robust network infrastructure. VPC simplifies routing configuration and management by presenting itself as a single logical switch, while routing protocols ensure that packets are routed efficiently to their destinations. By building a redundant environment, dividing traffic equally, keeping an eye on the condition of the peer link, enabling gentle shutdown, and integrating with other high availability technologies, VPC offers high availability and disaster recovery. This guarantees that in the case of a failure, the network can still function. These are the top 10 Nexus Interview Questions on vPC. Let’s now move on to Nexus Switch Interview Questions. Here are the top 10 Interview Questions on Nexus Switch: Initially, F Series cards were introduced for Layer 2 functionality only; now, advanced F Series cards have Layer 3 capability and new features. M series Modules support Layer 2 and Layer 3. At least one M1 series port should be in a VDC to be able to do routing. F1 series modules can use Proxy routing using M Series ports which are part of VDC. In shared mode, ports that are part of a group will share the total capacity. Let’s take an example of N7K-M132XP-12, which has 32 10G ports; it means that each port group (group of 4 ports for this line card) will share a 10G speed of total bandwidth among group members, and all ports will not get 10G of dedicated bandwidth. So, the total capacity of the card is 80G, not 320 (32x10G), because there can be eight-port groups of 4 ports each. Therefore, four ports in a group will share the total available bandwidth of 10G, which means oversubscription becomes 4:1. 1,3,5,7 will be in the same port group, and 2,4,6,8 and so on. In Dedicated mode, only one interface gets dedicated bandwidth, 10G in the case of the N7K-M132XP-12 line card. The other three interfaces in the group are disabled since only one interface is used in dedicated mode. On a Cisco nexus Line card, the dedicated ports are easily distinguished by their yellow colour. We must first shut down all four of the ports in the group, then switch the rate mode to dedicated, and finally, open the port to configure it as a dedicated port. The command to set the mode is “rate-mode dedicated” inside an Interface. FEX (Nexus 2000) stands for Fabric Extender, a dumb switch that acts as a line card in a parent switch (Nexus 5K or 7K or 9K). It does not have its own IOS or CPU for the control plane, and it downloads the image from the parent switch and appears as a module. It is primarily used when we need more interfaces for connecting servers; however, the management will happen from the parent only. The FEX front ports for servers are connected the same way as others. As long as we have a cable connected between the VDCs and the configuration is correctly done, then servers will communicate. VDCs are virtual switches, and one physical chassis may have multiple VDCs, so each VDC would work independently. Therefore, we need a cable connection between VDCs even if these reside in the same physical chassis. OTV (Overlay Transport Virtualization) offers layer 2 extension capabilities between various data centres. We can extend LANs between Data Centers with the help of OTV, which is an NX-OS feature. OTV is transport-independent, meaning that nearly anything that can transmit IP can be used for communication between data centres, including L2, L3, and even IP switched. Before making any changes, you may always take a snapshot (backup) of the Cisco Nexus configuration with the Cisco NX-OS checkpoint feature. The original configuration can be restored and rolled back using the captured configuration (checkpoint). Checkpoints are typically employed in rollback circumstances. They enable you to modify the system and, if an error arises, roll back to a previous stable configuration. When working on a piece of vital equipment, this function is very crucial. Fibre Channel over Ethernet, or FCOE, is a technique that uses Ethernet to encapsulate Fibre Channel frames. This makes it possible for data centre networking and storage to come together, allowing data and storage traffic to be carried over a single network. Nexus switches support FCOE by providing the following features: The deployment of unified fabric environments—where data centre networks and storage networks merge into a single infrastructure—is made possible by Nexus switches’ support for these functionalities. This can lower expenses, streamline network administration, and boost efficiency. LACP stands for Link Aggregation Control Protocol, which is used to aggregate multiple physical links into a single logical link. On the interfaces of the two devices that require aggregation, LACP is set up. The devices decide on the aggregation’s characteristics and negotiate the LACP mode (passive or active). Once the negotiation is over, the physical links are combined into one logical link. LACP equitably distributes traffic among the aggregated links using a hash-based method. It also keeps an eye on each physical link’s condition and automatically redistribute traffic over the remaining links in the event of a link failure. Nexus Switches comes with a set of security features to protect your network infrastructure. Here is a list of some of the most important security features: By using these features, you can easily enhance the security of your network based on nexus switches. These are the top 20 most asked Cisco Nexus Interview questions and answers. We hope you like these questions and wish you all the best for the interview. If you, as a network engineer, feel stuck at a package that is not your worth, you can check out our 100% Job Guarantee Course, a perfect program to learn all the latest and trending skills to get ahead in your career. If you are looking for more Cisco Nexus interview questions, you can get this PDF containing more than 40 important interview questions. All you have to do is to enter your Email address in the form below, and you will get an Email containing the link to download the interview questions. In this blog, we have covered the top 20 Cisco Nexus Interview Questions with their answers and also provided a PDF for more interview questions. Preparing for a interview requires a solid understanding of the technology and with these questions and answers, you should have covered some key areas. By practicing these questions, you will be well prepared for any Nexus Interview.
About Cisco Nexus
Cisco Nexus Interview Questions and Answers
Nexus vPC Interview Questions and Answers
Q1 – What is vPC, and what are its benefits?
Q2 – What are the components of vPC?
Q3 – What do you mean by “vPC Peer-Switch”?
Q4 – What do you mean by “vPC Peer-Link”?
Q5 – What do you mean by “vPC Keep-Alive”?
Q6 – What are Member Ports in vPC?
Q7 – What are Orphan Ports in vPC? What is the command to check the Orphan Ports?
Q8 – What is the possible reason I cannot use the “vPC domain” command on Nexus Switch?
Q9 – Does vPC interact with routing protocols like OSPF, EIGRP, or BGP?
Q10 – How does vPC support high availability and disaster recovery?
Cisco Nexus Switch Interview Questions and Answers
Q11 – What is the main Difference between M series Line Card and the F Series?
Q12 – Explain “Shared Mode” in Nexus Switches?
Q13 – Explain “Dedicated Mode” in Nexus Switches?
Q14 – What do you mean by “FEX”?
Q15 – Can a device in one VDC communicate with a device in another VDC?
Q16 – Please explain the concept of OTV?
Q17 – What is the concept of “checkpoint” in Nexus?
Q18 – What is FCOE and how is it supported by Nexus Switches?
Q19 – What is LACP?
Q20 – What are the security features available on Nexus Switches?
Cisco Nexus Interview Questions and Answers PDF
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