Chapter 2 : Basic Switch and End Device Configuration

 kernel The portion of the operating system that interacts directly with computer hardware.

Shell The portion of the operating system that interfaces with applications and the user.

Graphical user interface (GUI) A user-friendly interface that uses graphical images and widgets, along with text, to indicate the information and actions available to a user when interacting with a computer.

Command-line interface (CLI) A user interface to a computer operating system or application that depends on textual commands being entered by the user.

Cisco Internetwork Operating System (IOS) Generic term for the collection of network operating systems used by Cisco networking devices.

Firmware Permanent software programmed into ROM memory.

Cisco Device Access Methods 

• Console Term used to describe data transfer that requires the establishment of a virtual circuit. 
• Secure Shell (SSH) A protocol that provides a secure remote connection to a host through a TCP application. 
• Telnet A non-secure network service that supports CLI access to a remote host. It also can be used to verify the application layer software between source and destination stations.

IOS NAVIGATION

Cisco IOS software separates management access into the following two command modes: 

• User EXEC mode: This mode has limited capabilities but is useful for basic operations. It allows only a limited number of basic monitoring commands and does not allow the execution of any commands that might change the configuration of the device. User EXEC mode is identified by the CLI prompt that ends with the > symbol. 
• Privileged EXEC mode: To execute configuration commands, a network administrator must access privileged EXEC mode. Higher configuration modes, such as global configuration mode, can be reached only from privileged EXEC mode. Privileged EXEC mode can be identified by the prompt ending with the # symbol. 

IOS Command Modes

Global configuration mode A mode used to configure global parameters or enter other configuration submodes, such as interface, router, and line configuration submodes.

ping A troubleshooting tool used to verify network connectivity by sending a packet to a specific IP address and waiting for the reply.

Traceroute (tracert) A command on many computer operating systems that discovers the IP addresses and possibly hostnames of the routers used by the network when sending a packet from one computer to another.

Virtual terminal (vty) A text-based logical interface on an IOS device. It is accessed using Telnet or SSH to perform administrative tasks. A vty line is also called a virtual type terminal.

Configuration Files 

Two system files store the device configuration:

• Startup-config: This is the saved configuration file that is stored in nonvolatile random-access memory (NVRAM). It contains all the commands that will be used by the device upon startup or reboot. Flash does not lose its contents when the device is powered off. 

• Running-config: This is stored in random-access memory (RAM). It reflects the current configuration. Modifying a running configuration affects the operation of a Cisco device immediately. RAM is volatile memory. It loses all of its content when the device is powered off or restarted.

IP Addresses

The use of IP addresses is the primary means of enabling devices to locate one another and establish end-to-end communication on the internet. Each end device on a network must be configured with an IP address.

Examples of end devices include:

• Computers (workstations, laptops, file servers, web servers)
• Network printers 
• VoIP phones 
• Security cameras 
• Smartphones 
• Mobile handheld devices (such as wireless barcode scanners).

IPv4 address A 32-bit number, written in dotted decimal notation, used by the IPv4 protocol to uniquely identify an interface connected to an IP network. It is also used as a destination address in an IP header to allow routing. As a source address, it enables a computer to receive a packet and to know to which IP address a response should be sent.

IPv6 address A 128-bit address written in hexadecimal used by the IPv6 protocol. IPv6 addresses are the successor of IPv4 addresses.

Switched virtual interface (SVI) A virtual interface for which there is no associated physical hardware on the device. An SVI is created in software. The virtual interfaces are used as a means to remotely manage a switch over a network. They are also used for routing between VLANs. 

CONFIGURE IP ADDRESSING

IPv4 address information can be entered into end devices manually or automatically using Dynamic Host Configuration Protocol (DHCP). To manually configure an IPv4 address on a Windows host, open the Control Panel > Network Sharing Center > Change adapter settings and choose the adapter. Next, right-click and select Properties to display the Ethernet Properties dialog,

Dynamic Host Configuration Protocol (DHCP) A protocol used to dynamically assign IP configurations to hosts. The services defined by the protocol are used to request and assign an IP address, a default gateway, and a DNS server address to a network host. 

Domain Name System (DNS) An internet-wide system by which a hierarchical set of DNS servers collectively hold all the name-to-IP address mappings, and DNS servers refer users to the correct DNS server to successfully resolve a DNS name.