Cisco Installation and Startup Settings

We will share very useful information about a switch included in the network or a newly purchased Cisco Installation.

We will use the console method to connect to a device such as a switch or router that has never been configured before. New Cisco products now come in plug-and-play mode. An Ip address is set on it. However, if you are going to add multiple new switches, this may cause conflicts because the default ip addresses will be the same.

The healthiest method is to access the CLI console interface of the device via the Serial-Console Port(RS-232 port) and perform the initial setup. In addition to this method, there are many models with web interface. If you are not very good at the console, you can also use the web interface.

Connecting to Serial Port (Management Port-RS232) with Console Cable

To access the management console of the Switch, connect to the RS-232 or RJ45 Management Console port on the back panel or front panel with the help of a console cable.

Since newer computers do not have a serial port, you need to have a“USB to RS232 Converter dongle“. Once connected, you can test the connection on any of your computer’s serial ports such as Com1, Com2, Com3.

When installing a Cisco Switch, you need to have a console software on your computer after providing the physical connection. Make your connection with one of the commonly used programs such as SecureCRT, Putty, Hyper Terminal.

Since we will have very little chance of finding a physical switch in a home education environment, we will perform this process on Cisco Packet Tracer.

Connect the computer to the console port of the switch by selecting the console cable (blue) via Rs-232. Then run the Terminal application from Desktop and the CLI will open.

Cisco Installation and Startup Settings

We connected to the switch through the console port and let’s start managing it. First, let’s give the switch a name.

Hostname

Switch> enable 
Switch# conf t
Enter configuration commands, one per line.  End with CNTL/Z.
Switch (config)# hostname SATINALMA-SW1
SATINALMA-SW1 (config)#

Cancel – Return to Initial State (No Command)

SATINALMA-SW1 (config)# no hostname
Switch (config)#

Switch Management Ip Address Identification

In order to manage the switch remotely, it will be enough to define a management ip address. For this

SATINALMA-SW1(config)#int vlan 1
SATINALMA-SW1(config-if)#ip address 192.168.1.100 255.255.255.0
SATINALMA-SW1(config-if)#no shutdown 

SATINALMA-SW1(config-if)#line vty 0 3

SATINALMA-SW1(config-line)#password Pp1234
SATINALMA-SW1(config-line)#login
SATINALMA-SW1(config-line)#

SATINALMA-SW1(config-line)#enable password 1234Pp
SATINALMA-SW1(config)#

Here the line vty 0 3 command allows 4 simultaneous connections. Set a password with the password command and then disable passwordless login with the login command. enable password command is the password that will be requested when enable command is written to the switch.

Switch Gateway Identification

Defining the default gateway on Cisco Switch is done as follows:

SATINALMA-SW1(config)#ip default-gateway 192.168.1.1

Remote Connection to Switch with Telnet

Let’s connect remotely to the Cisco Switch that we made the initial setup settings via the Management Console. To do this, run the CMD Prompt application on the PC Desktop and type the following commands in order.

c:\> telnet 192.168.1.100

Password: 

SATINALMA-SW1> enable
Password:

SATINALMA-SW1# 

Let’s define a gateway for this device. For this, let’s connect the switch to a Router with ip address 192.168.1.1. If we want to ask for a password for users who will connect remotely.

Router(config)# line console 0
Router(config-line)#password Pp1234
Router(config-line)#login
Router(config-line)#end

Seeing the Running Configuration on a Switch or Router

We are slowly coming to the end of the Cisco Switch Installation process. Now it is time to print the configuration to the screen.

Printing Router Configuration

Router#show startup-config

Using 988 bytes
!
version 15.1
no service timestamps log datetime msec
no service timestamps debug datetime msec
no service password-encryption
!
hostname Router
!
!
!
!
!
!
!
!
no ip cef
no ipv6 cef
!
!
!
!

Printing Switch Configuration

SATINALMA-SW1# show running-config 
Building configuration...

Current configuration : 1215 bytes
!
version 15.0
no service timestamps log datetime msec
no service timestamps debug datetime msec
no service password-encryption
!
hostname SATINALMA-SW1
!
enable password 1234Pp
!
!
!
no ip domain-lookup
!
!
!
spanning-tree mode pvst
spanning-tree extend system-id
!
 --More-- 

Show running-config prints the running configuration while Show startup-config prints the startup configuration.

Network Packages

Unicast Packets

The message from a source only goes directly to the destination computer.

Broadcast Paketler

A message packet from one source goes to all devices on the network.

Multicast Packets

Messages from one source go to a group of devices.

How Does a Switch Learn MAC Addresses on the Network?

Switches are Layer 2 devices. They hold the MAC address(es) connected on each port. Switches do not support layers with protocols and applications.

It broadcasts a message using a Destination-Source binary. When the message reaches the switch, it learns the mac address of the connected device and writes it to the port memory. It sends the destination mac address of the message to all devices on the network. When it finds the device with this mac address, it opens the message packet and broadcasts a reply message. When this packet reaches the source computer, the Switch maps these MAC addresses and creates a Mac Table.

Message (packet) Delivery Modes

Half Duplex Mod

In this mode only one way (outgoing or incoming) communication is allowed at a time. This is how the dumb switches and hubs we used to use used to work.

Full Duplex Mod

This is the mode where two-way message traffic is allowed at the same time. This means that incoming and outgoing packets can be broadcast simultaneously. Smart Switches are built to work in this mode.