Designing a network with high availability in mind is a vital aspect of network architecture. Employing redundancy in both physical network links as well as network devices is a fundamental part of such design. Cisco’s Virtual Port Channel (vPC) is a technology that delivers a high degree of redundancy, providing mission-critical enterprise and datacenter networks […]
About Lazaros Agapidis
Lazaros Agapidis is a Telecommunications and Networking Specialist with over twenty years of experience.
He works primarily with IP networks, VoIP, Wi-Fi, and 5G, has extensive experience in training professionals for Cisco certifications, and his expertise extends into telecommunications services and infrastructure from both an enterprise and a service provider perspective.
In addition to his numerous vendor certifications, Lazaros has a solid online presence as an expert in his field, having worked in both public and private sectors within North America and in Europe.
He has enjoyed sharing his practical experiences in writing as well as through engaging online training.
Follow Lazaros at LinkedIn: Lazaros Agapidis or at his Youtube Channel.
What is a Wildcard Mask – All About Wildcard Masks Used in Networking
A wildcard mask is a bitmask used with IPv4 to specify ranges of IP addresses, which are then leveraged by various features, including access control lists and routing protocols. There’s a lot more to wildcard masks than meets the eye, and they’re a lot more powerful than you may initially think. In this article, we’ll […]
Comparison of Interface MTU vs IP MTU vs MSS in Computer IP Networks
Packet-based communication networks that operate using protocols like IP follow layered models such as the OSI and TCP/IP frameworks. These models involve the encapsulation and decapsulation of protocol data units (PDUs) through the addition and removal of headers at each layer. Two key parameters involved in this encapsulation process are the Maximum Transmission Unit (MTU) […]
Discussion and Explanation of BPDU Guard (With Cisco Config Example)
Spanning Tree Protocol (STP) is a mechanism that is used on network switches to eliminate layer 2 loops. Within the framework of STP operations, there are various additional features that can be enabled to further protect a topology from malicious users that may attempt to leverage STP to their advantage. BPDU Guard is one of […]
Explanation and Comparison of STP vs RSTP Protocols
Spanning Tree Protocol, or STP is an important part of Layer 2 networking. STP is virtually ubiquitous in switches of all types, including both managed and unmanaged devices from a multitude of vendors. Over the years, various newer versions of the protocol have been introduced, further refining, perfecting, and accelerating the functionality of this vital […]
Cisco IOS Configuration Command Modes Explained with Examples
Cisco’s command line interface (CLI) is a powerful tool that allows network administrators to configure network devices such as routers, switches, firewalls and others. In this article, we’ll examine the major configuration modes that are available within the IOS framework, how to enter them, how to recognize them, and what primary configuration parameters and commands […]
Should Servers be on Their Own VLAN in an Enterprise Network?
When it comes to network design, it is typically considered best practice to place your network servers within their own dedicated VLAN. But why? And is this always the case or are there situations in which you would use a different approach? In this article we’ll examine these questions and more about how to deploy […]
Redistribution and OSFP – Discussion With Cisco Commands Examples
Redistribution in networks and in particular, in the context of IP routing, refers to the process of transferring or injecting routing information from one routing protocol or domain, into another. OSPF, as a routing protocol, can either be the protocol from which routes are redistributed, into which routes are redistributed, or both! In this article, […]
What is SFTP – Discussion of SSH File Transfer Protocol
File transfers are an important network service. There are many protocols that can achieve this function, however, the SSH File Transfer Protocol, or SFTP is one of the safest, most efficient, and most popular methods around. It is arguably the most relied upon secure file transfer protocol used today! Image by freepik In this article, we’ll […]
SNMP Security in Networks: Best Practices and Common Pitfalls
The Simple Network Management Protocol (SNMP) has long been a fundamental part of monitoring and managing network devices such as routers, switches, firewalls, access points, servers, and many others. Its simplicity and universal support make it a powerful tool for network administrators. However, its ease of use comes at a cost: if not properly secured, […]
Cisco HSRP States and Troubleshooting (With Commands)
Hot Standby Router Protocol or HSRP is a Cisco proprietary first hop redundancy protocol that is used to configure default gateway redundancy. With HSRP (like other gateway redundancy protocols), two or more routers can achieve default gateway failover in the event that the primary gateway fails or becomes inaccessible. In this article, we will focus […]
Discussion and Explanation of Route Maps in Networking
Route maps are a powerful tool used to manipulate routing information and policies within a network. They allow network administrators to control and influence how routes are advertised, received, and selected on Cisco routers. Route maps are extremely versatile and can be used in conjunction with routing protocols and other features to very granularly manipulate […]
How are Networks Advertised Using BGP? With Cisco Config Examples
Border Gateway Protocol (BGP), as an exterior gateway protocol, is in a class on its own. It is the de facto standard routing protocol used on the Internet. Unlike its Interior Gateway Protocol (IGP) cousins, such as OSPF or EIGRP, BGP advertises networks in a somewhat different way. In this article, we will highlight the […]