Author: Joshua

Network Topology Types

Network Topology Types

Network topology can be defined as the layout pattern and connectivity scheme between the devices in a network. It is simply the layout of network communication. There are two main types of Network topology, and they are Physical and Logical Network topology. Physical Network Topology: Physical topology is the actual connectivity or layout according to real cabling & connections Logical Network Topology: Logical topology is the virtual view of the network devices see   Physical Topology Under the physical topology, there are about seven topologies:  Point-to-Point Network Topology  Star Network Topology  Ring Network Topology  Mesh Network Topology  Tree Network Topology  Bus Network Read More …

QoS (Quality of Service)

QoS Quality of services

QoS (Quality of Service) is simply Traffic discrimination. QoS in Networking can also be defined as a set of technologies used to manage traffic and ensure the performance of critical applications. It enables firms or organizations to adjust their entire network by prioritizing certain high-performing applications.   Problems Solved by Quality of Service (QoS) in Networking The problems that QoS solves are: It provides predictable management of network resources during times of congestion It helps in maximizing the end-user experience of critical sessions It provides differentiated services to packets based on pre-defined user criteria Factors affected by Quality of Service Read More …

Port Security

Port Security

Layer-2 Port Security is used for network traffic control. It allows only the authorized user or filtered MAC address configured to gain access to the network.   Enabling mode Pass/Secret in Port Security To enable mode Pass/Secret we have to Secure the Privileged Mode Access. An encrypted Password is recommended (enable secret)   Example of How to Enable mode Pass/Secret Below is an example of how to enable mode Pass/Secret on the IOS Command Line Interface: R1(config)# enable password networkwalks R1(config)# enable secret networkwalks   Secure the Console (local Access) Secure the Local access by adding a password to Console Read More …

ACL (Access Control List)

acl-access-control-lists 2

ACL (Access Control List) is a list of rules that specifies which users or systems are allowed access to a particular object or system resource. It can simply be defined as a set of instructions to filter inbound and outbound traffic on an interface.   Access Control List Overview and Access List Concepts Access Control List carries out a packet identification mechanism and can also identify packets on the basis of Layer 3 and Layer header. Each access list is composed of one or more ACEs (Access Control Entries) and each ACE is assigned a sequence number. ACEs are processed Read More …

Firewalls and VPNs

VPN

Firewalls are network security devices that monitor and control incoming traffic and outgoing traffic based on a pre-defined set of rules, while VPNs (Virtual Private Networks) are security services that allow devices to access the internet as if they were connected to a private network. Firewalls and VPNs (Virtual Private Networks) in general are both used for security purposes on the network What are Traditional Firewalls? Traditional firewalls sit in the forwarding path. They protect the network from different kinds of issues by allowing only the intended types of traffic to flow in and out of the network, as shown Read More …

STP (Spanning Tree Protocol)

STP (Spanning Tree Protocol) is a Layer-2 protocol that builds a loop-free network topology. Only one active path can exist between two stations in order for them to function properly. STP is a Network Protocol (Layer2) and has a Standard of IEEE 802.1D/W/S/Q, Cisco (Def on Cisco=PVST). Its function is to prevent Layer2 Loops within a network topology, adapt to network changes and failures. The STP Algorithm was designed by Radia Perlman. Spanning Tree Protocol has a Multicast Address of 01:80:C2:00:00:00,  01:00:0C:CC:CC:CD (Cisco’s PVST). There are 5 STP port states and 3 RSTP port states. Likewise, there are 3 STP Read More …

EtherChannel

etherchannel

What is EtherChannel? EtherChannel is a Layer-2 link aggregation protocol which is used to combine multiple physical links to a single logical link called an EtherChannel bundle or a PortChannel. It is a Cisco Proprietary and IEEE 802.3ad (2000) is a standard way of carrying out Link Aggregation. The purpose of EtherChannel is to achieve Link Aggregation or Logical Bundling. The no. of member ports are between 2 – 8 (a maximum of 8 active out of a total of 16 on most Cisco Switches). EtherChannel has a multicast address of LACP:01-80-c2-00-00-02,  PAgP:01-00-0C-CC-CC-CC   Why do we need EtherChannel in Read More …

BGP (Border Gateway Protocol)

BGP-routing-protocol

BGP (Border Gateway Protocol) is an open source, dynamic Exterior Gateway protocol designed to exchange routing and reachability information among various Autonomous Systems on the IP Networks and the Internet. It is a path-vector protocol type and uses the Composite metric (based on 11 factors usually) as its metric value.  It is an EGP (Exterior Gateway Protocol) used for routing the internet. BGP has 4 (Open, Update, Keepalive, Notification) no. of packets and has an Admin Distance of 20 (eBGP), 200 (iBGP). Its neighbor type is Statically (manually) configured and has 6 no. of neighbor states. BGP uses TCP connection Read More …

EIGRP Protocol

eigrp-routing-protocol

EIGRP (Enhanced Interior Gateway Routing) is a dynamic routing protocol for IP networks. It is considered a hybrid protocol type that supports a classless routing technique and uses the Diffusing Update Algorithm (DUAL) to help improve protocol efficiency and routing calculations. EIGRP was designed as a Cisco proprietary protocol for Cisco routers and uses composite metrics (BW, Load, Delay, Reliability, MTU). Enhanced Interior Gateway Routing Protocol uses MD5 and SHA-256 for authentication. It uses an admin distance of 90 for internal routes, 170 for external routes, and 5 for summary routes. EIGRP has a multicast address of 224.0.0.10 and supports Read More …

WLAN and WiFi Infrastructure

wlan-wifi-topologies

WLAN and WiFi Infrastructure refers to concepts like LAN topologies, pairing lightweight APs and WLCs, and finally, leveraging antennas for wireless coverage. It is very important to understand these concepts for computer networking & certifications like Cisco CCNA, CCNP, CCIE, CompTIA Network+, Huawei HCNA & Cybersecurity.   Wireless Infrastructure WLAN Topologies This concept explains autonomous, cloud-based centralized, embedded, and mobility wireless architectures.   Autonomous Topology Autonomous access points (APs) are self-contained and offer one or more standalone basic service sets (BSSs). They are an extension of a switched network, connecting wireless service set identifiers (SSIDs) to wired VLANs at the Read More …