Switching Architectures - Network Traffic Models

Network Traffic Models Traffic flow is an important consideration when designing scalable, efficientnetworks. Fundamentally, this involves understanding two things:• Where do resources reside?• Where do the users reside that access those resources? Legacy networks adhered to the 80/20 design, which...

Switching Architectures - The Cisco Hierarchical Network Model

The Cisco Hierarchical Network Model To aid in designing scalable networks, Cisco developed a hierarchicalnetwork model, which consists of three layers: • Access Layer• Distribution layer • Core layer Cisco Hierarchical Model – Practical Application ...

Switching Architectures Hierarchical Model – Practical Application

Cisco Hierarchical Model – Practical Application The above example illustrates common block types:• User block – containing end users• Server block – containing the resources accessed by users• Edge block – containing the routers and firewalls that connect usersto the WAN or InternetEach...

Switching Architectures Hierarchical Model – Core Layer

Hierarchical Model – Core Layer The core layer is responsible for connecting all distribution layer switches. The core is often referred to as the network backbone, as it forwards trafficfrom to every end of the network. Switches at the core layer typically have the following characteristics:•...

Switching Architectures Hierarchical Model – Distribution Layer

Hierarchical Model – Distribution Layer The distribution layer is responsible for aggregating access layer switches,and connecting the access layer to the core layer. Switches at the distributionlayer typically have the following characteristics:• Layer-3 or multilayer forwarding•...

Switching Architectures Hierarchical Model – Access Layer

Hierarchical Model – Access Layer The access layer is where users and hosts connect into the network. Switches at the access layer typically have the following characteristics:• High port density• Low cost per port• Scalable, redundant uplinks to higher layers• Host-level functions...

Cisco Switch ADSL Port Configuration Best Practice - straight forward and Easy

 ADSL Port Configuration  only change  yellow shaded text interface GigabitEthernet0/2 description "CONNECTED TO INT" no ip address duplex auto speed auto pppoe enable group global pppoe-client dial-pool-number 1! interface GigabitEthernet0/1 ip nat inside no cdp enable interface Dialer1 bandwidth 100000 ip address negotiated no...

Cisco Switch Configuration Best Practice - straightforward and Easy

Advanced straight  Layer 3 switch configuration only replace the highlighted Words   no ip routing no service padservice tcp-keepalives-inservice tcp-keepalives-outservice timestamps debug datetime localtime show-timezoneservice timestamps log datetime localtime show-timezoneservice password-encryptionservice internalservice pt-vty-loggingservice sequence-numbersservice counters...

What is a VLAN, And Layer Function

VLANs – A Layer-2 or Layer-3 Function? By default, a switch will forward both broadcasts and multicasts out every port but the originating port. However, a switch can be logically segmented into multiple broadcast domains, using Virtual LANs (or VLANs). VLANs are covered in extensive detail in another guide. Each VLAN represents a unique broadcast domain: • Traffic between devices within...

What is Layer 3 Switching

Layer-3 Switching In addition to performing Layer-2 switching functions, a Layer-3 switchmust also meet the following criteria:• The switch must be capable of making Layer-3 forwarding decisions(traditionally referred to as routing).• The switch must cache network traffic flows, so that Layer-3forwarding...

The Difference Between Layer 3 Switching and Routing

Layer-3 Switching vs. Routing – End the Confusion! The evolution of network technologies has led to considerable confusionover the terms switch and router. Remember the following:• The traditional definition of a switch is a device that performs Layer-2forwarding decisions.• The traditional definition of a router is a device that performs Layer-3forwarding decisions. Remember also that, switching...

What Is Multilayer Switching

Multilayer Switching Multilayer switching is a generic term, referring to any switch thatforwards traffic at layers higher than Layer-2. Thus, a Layer-3 switch isconsidered a multilayer switch, as it forwards frames at Layer-2 and packetsat Layer-3. A Layer-4 switch provides the same functionality...

difference between Hubs, Switches, Routers

Hubs vs. Switches vs. Routers layered communication, The OSI model Icons for Network Devices The following icons will be used to represent network devices: Details Are in Below Links : Layer - 1 Hubs Layer 2 Switching Layer-3 Routing ...

What Is Layered Communication, the OSI model

Layered Communication Network communication models are generally organized into layers. TheOSI model specifically consists of seven layers, with each layerrepresenting a specific networking function. These functions are controlledby protocols, which govern end-to-end communication between devices. As...

What is Routing Layer 3

Layer-3 Routing Layer-3 routing is the process of forwarding a packet from one network toanother network, based on the Network-layer header. Routers build routingtables to perform forwarding decisions, which contain the following:• The destination network and subnet mask• The next hop router to get to the destination network• Routing metrics and Administrative Distance Note that Layer-3 forwarding...

Diffrence Between Collision And Broadcast Domain

Collision vs. Broadcast Domain Example Consider the above diagram. Remember that:• Routers separate broadcast and collision domains.• Switches separate collision domains.• Hubs belong to only one collision domain.• Switches and hubs both only belong to one broadcast domain. In the above...

What is layer 2 switching

Layer-2 Switching Layer-2 devices build hardware address tables, which at a minimumcontain the following:• Hardware addresses for hosts• The port each hardware address is associated with Using this information, Layer-2 devices will make intelligent forwardingdecisions based on the frame (or data-link)...

Layer 2 Forwarding Types

Layer-2 Forwarding Methods Switches support three methods of forwarding frames. Each method copiesall or part of the frame into memory, providing different levels of latencyand reliability. Latency is delay - less latency results in quicker forwarding. The Store-and-Forward method copies the entire frame into memory, andperforms a Cycle Redundancy Check (CRC) to completely ensure theintegrity...

What are network layer 1 network hubs

Layer-1 Hubs Hubs are Layer-1 devices that physically connect network devices togetherfor communication. Hubs can also be referred to as repeaters. Hubs provide no intelligent forwarding whatsoever. Hubs are incapable ofprocessing either Layer-2 or Layer-3 information, and thus cannot makedecisions based on hardware or logical addressing. Thus, hubs will always forward every frame out every port,...

Power over Ethernet (POE)

Power over Ethernet (PoE) Power over Ethernet (PoE) allows both data and power to be sent acrossthe same twisted-pair cable, eliminating the need to provide separate powerconnections. This is especially useful in areas where installing separatepower might be expensive or difficult. PoE can be used to power many devices, including:• Voice over IP (VoIP) phones• Security cameras• Wireless access points•...

Ethernet Twisted-Pair Cabling – Cable and Interface Types

Ethernet Cable Types The layout or pinout of the wires in the RJ45 connector dictates the functionof the cable. There are three common types of twisted-pair cable:• Straight-through cable• Crossover cable• Rollover cable The network interface type determines when to use each cable:• Medium Dependent Interface (MDI)• Medium Dependent Interface with Crossover (MDIX)Host interfaces are generally MDI,...

Twisted-Pair – Rollover Cable arrangment

Twisted-Pair – Rollover Cable A rollover cable is used to connect a workstation or laptop into a Ciscodevice’s console or auxiliary port, for management purposes. A rollovercable is often referred to as a console cable, and its sheathing is usually flatand light-blue in color. To create a rollover...

Twisted Pair Cabling – Crossover Cable

Twisted-Pair Cabling – Crossover Cable A crossover cable is used in the following circumstances:• From a host to a host – MDI to MDI• From a hub to a hub - MDIX to MDIX• From a switch to a switch - MDIX to MDIX• From a hub to a switch - MDIX to MDIX• From a router to a router - MDI to MDI Remember...

Ethernet Cable Twisted Pair Overview

Twisted-Pair Cabling Overview A typical twisted-pair cable consists of four pairs of copper wires, for atotal of eight wires. Each side of the cable is terminated using an RJ45connector, which has eight pins. When the connector is crimped onto thecable, these pins make contact with each wire. The...

Twisted Pair Types - Straight-Through Cable

Straight Cable Twisted-Pair Cabling – Straight-Through Cable A straight-through cable is used in the following circumstances: • From a host to a hub – MDI to MDIX • From a host to a switch - MDI to MDIX • From a router to a hub - MDI to MDIX • From a router to a switch - MDI to MDIX Essentially,...

Speed and Duplex Autonegotiation

Speed and Duplex Auto negotiation Fast Ethernet is backwards-compatible with the original Ethernet standard.A device that supports both Ethernet and Fast Ethernet is often referred to asa 10/100 device. Fast Ethernet also introduced the ability to autonegotiate both the speed andduplex of an interface. Autonegotiation will attempt to use the fastest speedavailable, and will attempt to use full-duplex...

Categories of Ethernet

speed and duplex auto negotiation Categories of Ethernet The original 802.3 Ethernet standard has evolved over time, supporting faster transmission rates, longer distances, and newer hardware technologies. These revisions or amendments are identified by the letter appended to the standard, such...

Full-Duplex Communication

Full-Duplex Communication Unlike half-duplex, full-duplex Ethernet supports simultaneouslycommunication by providing separate transmit and receive paths. Thiseffectively doubles the throughput of a network interface. Full-duplex Ethernet was formalized in IEEE 802.3x, and does not useCSMA/CD or slot times. Collisions should never occur on a functional fullduplexlink. Greater distances are supported...

CSMA/CD and Half-Duplex Communication

CSMA/CD and Half-Duplex Communication Ethernet was originally developed to support a shared media environment.This allowed two or more hosts to use the same physical network medium. There are two methods of communication on a shared physical medium:• Half-Duplex – hosts can transmit or receive, but not simultaneously• Full-Duplex – hosts can both transmit and receive simultaneously On a half-duplex...

The Ethernet Frame

The Ethernet Frame An Ethernet frame contains the following fields: The preamble is 56 bits of alternating 1s and 0s that synchronizescommunication on an Ethernet network. It is followed by an 8-bit start offrame delimiter (10101011) that indicates a valid frame is about to begin.The preamble...

Network Topologies

A topology defines both the physical and logical structure of a network.Topologies come in a variety of configurations, including:• Bus  : Bus Topology • Star  : Star Topology• Ring • Full or partial mesh Ethernet supports two topology types – bus and sta...

Ethernet Star Topology

Ethernet Star Topology In a star topology, each host has an individual point-to-point connection to acentralized hub or switch: A hub provides no intelligent forwarding whatsoever, and will alwaysforward every frame out every port, excluding the port originating the frame.As with a bus topology,...

Ethernet Bus Network Topology

Ethernet Bus TopologyIn a bus topology, all hosts share a single physical segment (the bus or thebackbone) to communicate: A frame sent by one host is received by all other hosts on the bus. However,a host will only process a frame if it matches the destination hardwareaddress in the...

Ethernet Cabling Types

Ethernet Cabling Types Ethernet can be deployed over three types of cabling: • Coaxial cabling – almost entirely deprecated in Ethernet networking • Twisted-pair cabling • Fiber optic cabling Coaxial cable, often abbreviated as coax, consists of a single wire surrounded by insulation, a metallic shield, and a plastic sheath. The shield helps protect against electromagnetic interference (EMI), which...

What is Ethernet?

Ethernet is a family of technologies that provides data-link and physicalspecifications for controlling access to a shared network medium. It hasemerged as the dominant technology used in LAN networking.Ethernet was originally developed by Xerox in the 1970s, and operated at2.94Mbps. The technology was standardized as Ethernet Version 1 by aconsortium of three companies - DEC, Intel, and Xerox, collectively...

Active directory Password Policy

1-     Enforce Password History: how frequently the old passwords can be reused (user can’t repeat the same Previous password on reset until the password has been reset 1/2/3/10 times) 2-     Maximum Password Age: how long a user can use the same password (1 day/ 10 days/20days etc.) 3-     Minimum Password Age: how many days or hours...