Ether channels - Cisco Switching PAgP, LACP

Ether channels

The ability to configure multiple physical links into one logical link is called an ether channel. Ether channels are a link aggregation technology and are also referred to a as port channel architecture. Once the ether channel has been configured the resulting virtual interface is called a port channel. The benefits of this are we can combine physical links to combine bandwidth, logically speaking two 100Mbps links combine into a 200Mbps link. An ether channel provides redundancy, if one port fails the other one is still active. An ether channel must be between 2 and 8 physical links

Below we will configure an ether channel in Cisco Packet tracer;

Link Aggregation Control Protocol (LACP)

LACP is an open standard which can be used by most vendors. Switch ports can form an ether channel in different LACP modes following the below criteria; 

-A port in the active mode can form an Ether Channel with another port that is in the active or passive mode.

-A port in the passive mode cannot form an Ether Channel with another port that is also in the passive mode because neither port starts LACP negotiation.

A port in active mode negotiates with the other side to form the Ether channel. The interface in passive mode indicates using LACP, but responds to requests only and does not send any requests.

LACP negotiation modes for channel establishment

LACP configurations;

Here are the configurations for LACP notice the mode is set to active. On a second switch the command are the same just replace active with passive.

Manual On Ether Channel mode

When using manual on mode an ether channel will be created only when another interface is using manual on mode. They forcefully form an ether channel without negotiation. 

Port aggregation protocol (PAgP)

PAgP is a Cisco proprietary ether channel technology. Switch Ports can form an Ether Channel when they are in different PAgP modes as per below criteria;

-A port in the desirable mode can form an Ether Channel with another port that is in the desirable or auto mode.

-A port in the auto mode can form an Ether Channel with another port in the desirable mode.

The port in desirable mode is one which sends requests to the other side to see if it is also using PAgP. The port in auto mode defines using PAgP but does not send requests. 

PAgP negotiation modes for channel establishment

PAgp configurations

Notice here we don't need to specify the protocol as this is default on Cisco switches. On another switch the mode would be set to auto

Spanning Tree Protocol - STP

Spanning Tree Protocol

The Spanning tree protocol (STP) is a loop free layer 2 technology. Without STP loops can occur on a network and result in a broadcast storm

Switches within the same network need to be enabled for STP before they run the spanning tree algorithm so they can accurately determine which switch should be elected the “root bridge.” This designated root bridge will be responsible for sending configuration bridge protocol data units (BPDUs) along with other information to its directly connected switches that, in turn, forward the BPDUs to their neighbouring switches. Each switch has a bridge ID priority value (BID), which is a combination of a priority value (default 32768) and the switch’s own MAC address. The switch with the lowest BID will become the root bridge.

STP Port States

There are five STP switchport states; these are:

• Disabled - The result of an administrative command that will disable the port.

• Blocking - When a device is connected, the port will first enter the blocking state.

• Listening -The switch will listen for and send BPDUs.

• Learning - The switch will receive a superior BPDU, will stop sending its own BPDUs, and will relay the superior BPDUs.

• Forwarding - The port is forwarding traffic.

STP Port Roles

• Root - Ports on non-root switches with the best cost path to root bridge. These ports forward data to the root bridge.

• Designated - Ports on root and designated switches. All ports on the root bridge will be designated.

• Blocked - All other ports to bridges or switches are in a blocked state. Access ports going to workstations or PCs are not affected.

Path cost

A switch may encounter one or more switches in its path to the root bridge. All paths are analysed and the path with the lowest cost is selected. Speed of ports are important and link speed relates to the port cost

Example Video with STP ; 

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Using Group Policy to deploy wallpaper to domain machines

On the server open up internet explorer, go to the website bing.com ( google may run slow ) . Search for an image of your choice

Right click on the image - and save it to the Pictures folder on the server as a bmp file 

Right click on the pictures folder and click share with specific people

Ensure everyone is added if not click the drop down box and add tick read/write and click share

Do the same for the file you want to use for example here I have right clicked on burnley2 and clicked share with specific people

Ensure Everyone + Read/write is selected and click share

You should see the below screen with the file name location listed. Mine is 

\\SERVER1\Users2\Administrator\Pictures\Burnley2.bmp

On server manager, click tools then Group policy management 

Right click Group Policy Objects - Click New 

Type Wallpaper then click ok

Now right click Wallpaper in the Group Policy Objects folder and click edit

Expand user configuration -> policies -> administrative templates then click desktop and on the right hand side click desktop wallpaper

Click enabled - type the full file path into the Wallpaper name , and select style as center or fill ( however you want the logo to appear. Click apply 

Go back to the group policy management console and right click your domain name - click Link an existing GPO

Select wallpaper

On the Windows 10 machine open cmd prompt 

Type gpupdate /force 

You should see the below message that is has been successfully update. Close the command prompt window and restart the windows 10 machine

Login with a user and you should see your logo if you have been successful :) 

Connect a Windows 10 machine to a domain

 

Select the Windows 10 machine and click start

Enter your password at the login screen

Press the Windows + X key and select system

Select rename this PC

Change the name to PC1

Click restart now

Press the windows + s key and type firewall and select the Windows defender firewall

Select turn windows defender on or off

Turn off both private and public settings

Press the Windows + X key and select system

Select Remote Desktop

Turn Remote Desktop On 

Click confirm

Press the Windows + X key and select network connections 

Click Change adapter options

Double click on the ethernet icon

Click properties

Uncheck IPv6 

Double click on Ipv4

Enter the IP address of your server from previous instructions below is my server's address . click ok 

Press the Windows + X key and select settings 

Select accounts

Select access work or school 

Select connect 

Select join this device to a local Active Directory domain 

Type your domain name

Type .\ ( then the username for which you made an administrator and the password )

Skip the below step and restart the PC

When the computer restarts you should see your domain name at the Sign in 

Type the user logins and press enter

New user has joined 👏

Close tabs down and shutdown the Windows 10 machine.