Several network devices available in the market operates at different levels of layers#. The following sections are organised in a way that the network devices are group together regarding their corresponding layer.
The following devices operate at Physical Layer# :
The following devices operate at Data Link Layer# :
The following devices operate at Network Layer# :
WAN is a network that covers a broad geographic area, which often uses service providers’ (SP) transmission facilities and operates on Physical Layer#, Data Link Layer# and Network Layer# to connect several #Local-Area Network (LAN). Several network devices could operate within WAN such as Switch# (at data link layer) and Router#.
We can apply access rules and provision services to the users of same or similar responsibilities without the need to change the topology of the network or changing the IP Address. Furthermore, VLAN can also create their own Broadcast Domain# without the help from Network Layer Network Device (modern #Switch and #Router). Basically, we could assign the hosts in a subnet# to be in the same VLAN. By using VLAN, we could have different broadcast domains even in a single switch so that broadcast flooding affects only those in the same grouping. If a link needs to handle more than one VLAN, #VLAN Trunking will be used.
Note: When assigning host addresses, use the last addressable address and work from there to the beginning. The Network Devices usually use the first and the following addressable addresses.
Switch is a #Network Device that can operates in either Data Link Layer# or Network Layer# (modern implementation). It is an intelligence Bridge, which provide superior throughput performance, more ports (lower per-port cost), high-speed connections, segmentation using Virtual LAN (VLAN)# or Broadcast Domain# (modern), and even routing (in the case of Multilayer Switch). This makes large-scale segmentation possible within the [Local-Area Network (LAN)](202207051554)❌.
Straight-Through Cable is a #Twisted Pair Cable where the pin mapping is identical from one end to the other end. It is used when connecting two different kinds of Network Device.
SNMP is a lightweight #Application Layer Protocol# allowing remote and local #management# of items or Network Device on the network. It is part of #Internet Protocol Suite (TCP/IP). SNMP comprises of two entities: agents who are running on managed node and collecting information about the node, and managers who are running on management workstation that requests information about devices on the network.
Router is a #Network Device operates at Network Layer# which forwards packets from source to destination based on network layers protocols (reading the source and destination IP Address). It will communicate with other routers using Routing Protocol# (dynamic routing) or be manually edited by network administrators (static routing) to maintain or update their Routing Table# that contain optimal routing paths. Of course Router needs to be connected to a network to establish either dynamic routing or static routing.
Repeater is a #202207051821 operates at 202206131647# which extends the range of the networks (i.e. 202207051554#). This is done by regenerate an electrical signal at the amplitude of the original signal.
The client from the user side will initiate a request to remote access server (which could be NAS or other Network Device, that has RADIUS client installed) to gain network access. The server will ask the user for credentials, which the user will provide. It forwards the request alongside with the authentication information to an AAA server, where it checks the information against the database that stores user information (e.g., Active Directory, Novell NetWare eDirectory, or UNIX NIS). The AAA server will return the success or failure of the authentication to the RADIUS client (that is the NAS in this case), and if it is a success, the remote access server will grant the network access to the user client.
Physical Topology Diagram is used to show the physical location of Network Device#, configured ports and cable installation#. It could be abstracted as Logical Topology Diagram.
NMS is a set of #hardware and/or #software tools that allows administration of individual components of a network within a larger Network Management# framework. It consists of Management Station or Manager#, Management Agent#, Management Information Base (MIB)#, and Network Management Protocol#. These components assist in Network Device# discovery, network device monitoring, network performance analysis, and intelligent notifications.
MBI is a representation of network resources as objects being managed. It is a collection point of access points at Management Agent for Management Station or Manager.
Management Agent is a Network Device# equipped with agent software from #Network Management System (NMS) which allow remote management from the Management Station or Manager. In addition of requiring to respond to requests for information and/or action, it asynchronously and voluntarily sends the manager its information.
LAN is a network that usually cover a small area such as a building or a home. The number of the devices can be connected to and the range of it can be enhanced by the Network Device. There are several protocols that make possible for the communication betweem the computers within the defined area:
Ethernet Hub is a #202207051821 operates at 202206131647# which enable devices to be plugged in or out without disturbing the #202207051550 network. Its ports also function as a 202207051832. Since it doesn’t have the information of the network topology, it will simply propagate the received package to every other port, which raises security concerns and wastes bandwidth.
DHCP is a protocol used for automatic #IPv4 Address assignment. Using this protocol, the network will be able to allot an available IP address to a Network Device# upon requested. It saves up network administrative costs and conserves IP address space.
Crossover Cable is a #Twisted Pair Cable where the pins 1 and 3, and pins 2 and 6 are swapped on one end of the cable. It is used to connect two Network Devices# of the same kind.
Classless Routing Protocols are the Routing Protocols that don’t follow the Address Classes subnet masking instead favour the Variable-Length Subnet Masking (VLSM)#. All protocols will include network mask when sending the routing information to other Network Device. It is aimed to replace Classful Routing Protocols.
Cisco IOS is a collection of network operating systems used on Cisco Network Devices#, usually stored at the flash of the device or TFTP server. It can be used from input and output devices. It also provides the mean for memory management, process management, file systems management, security management, hardware management, network interface configuration, and enabling routing# and switching# functions.
Global Configuration will show up when the command configure is executed in Privileged EXEC. From here, we can configure the settings for the Network Device#.
Broadcast Domain is a network segment where a device can receive all broadcast messages from the members of the segment. It is usually segmented by Network Layer# Network Device# (modern #Switch and #Router).
Bridge is a #202207051821 operates at 202206131651# which provides the ability to split the #202207051805 into smaller ones, controls data flow, handles transmission error and enables access to physical device.
AS is a #logical network segment that contains several Network Devices# especially Routers# under a common administration sharing a common routing strategy. An AS is typically identified using 16-bit autonomous system number (ASN) given by the American Registry of Internet Numbers (ARIN), an Internet Service Provider (ISP) or a network administrator. It is a basic unit in Routing inside AS involves #IGP whereas routing outside AS involves #EGP.