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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 …

Wireless WiFi Roaming

wireless wifi roaming

Understanding wireless & WiFi Roaming is very important in WLAN and WiFi computer networking. It occurs when a wireless client moves around in a region with many access points (APs). It may switch automatically to another access point (AP) with more preferred signal strength.   Understanding Wireless Roaming Types The wireless roaming types are: Intra-Controller roaming, Roaming between controllers (L2 Roaming and L3 Roaming), and Roaming between Autonomous APs   Understanding Wireless & WiFi Roaming between Centralized Controllers Also referred to as Inter-controller roaming. In this case, as the wireless network expands there are chances that the client needs to Read More …

Signals and Modulation of WiFi / Wireless

wireless-wifi-signals-modulation

Signals and Modulation of WiFi & Wireless are very important networking concepts for computer networking & are used in wireless communication. Wireless signals are crucial since they can transmit data in form of audio, video, etc without cables or wires. Modulation is the process of converting information signals into a different form. Some of the common types of wireless signals include Television and Radio Broadcasting, satellite, Global Positioning Systems (GPS), Bluetooth, Cellular phones, Wi-Fi, cellular phones, etc.   Wireless Signal terms Some of the important wireless terms are listed below: Frequency is defined as the number of cycles completed per Read More …

Network Assurance & Troubleshooting approaches

network assurance and troubleshooting

Network Assurance & troubleshooting is the act of finding network issues through a testable process and using provable methods to solve them. Network troubleshooting and assurance are implemented when there is a network failure or something bad happens to the network, to help diagnose and solve the issue. Network troubleshooting and assurance are implemented by network engineers to resolve network issues and improve operations   General Network Assurance & Troubleshooting Approach A structured network troubleshooting method is simply a guideline throughout the troubleshooting process. There are many approaches that we can choose from. The key to all structured troubleshooting methods Read More …

Network Troubleshooting Utilities and Tools

How to do network troubleshooting

Network Troubleshooting utilities and tools are used by network engineers to diagnose and resolve network issues or problems. The common type of network troubleshooting utilities and tools is the command-line tools and they include: ping, traceroute, debug, etc.   1. Ping (Network troubleshooting utilities) Ping as one of the network troubleshooting utilities and tools is one of the most valuable and well-known troubleshooting tools in networking. It uses a protocol known as ICMP (Internet Control Message Protocol). Ping uses two ICMP message types: Type8/Code0 (Echo Request) and Type0/Code0 (Echo Reply). When you issue a ping command, the source sends an Read More …

Wireshark

wireshark

What is Wireshark? Wireshark is an open-source free packet sniffer and analysis network troubleshooting tool. It captures network traffic on the local network and stores that data for offline analysis. Wireshark can be set up in software form for local traffic of servers/computers. For network setup, we need to enable a port mirroring solution to send all traffic where the Wireshark terminal is connected as shown in this diagram.   Uses of Wireshark (network troubleshooting tool) The uses of Wireshark are: It can be used by network engineers to examine security problems. It is used by network engineers to troubleshoot Read More …

SNMP (Simple Network Management Protocol)

snmp

What is SNMP? SNMP (Simple Network Management Protocol) is a Layer-7 protocol for collecting and organizing information about managed devices on IP networks and for modifying that information to change device behavior. It allows devices to communicate even if the devices are different hardware and run different software. There are two major types of devices in SNMP, they are Managed devices which are devices being managed using SNMP and Network Management Station (NMS) which could be a device or devices managing the managed devices. It could also be seen as the SNMP server.   Features of SNMP (Simple Network Management Read More …