Demo router on Stick con DHCP en Servidor

El concepto de Router on Stick es básicamente hacer que una interfaz de red del router pueda funcionar como un servidor de puerta de enlace para muchas VLANS diferentes, eso se logra creando sub interfaces en la interfaz principal.
Se utilizo el simulador Packet Tracer, para realizar la tarea. Se uso un router 1841, y un switch 2950-24

Para el desarrollo de este demo es necesario hacer tres tipos de configuraciones diferentes para llegar al resultado final. Primero es necesario crear las sub interfaces, luego las VLANS y por ultimo configurar el servicio de DHCP.

Asignarle dirección ip al router

Router (config) #interface fasethernet0/0
Router (config-if) #ip address 192.168.1.1 255.255.255.0
Router (config-if) #no shutdown

Crear las sub Interfaces:

En las telecomunicaciones y las redes de computadoras, un sub interface es una división de una interfaz física en múltiples interfaces lógicas.
Para crearla es muy fácil, simplemente estar en modo interface

Router>enable
Router# configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
Router (config) # interface fastEthernet 0/0.10 //Aqui se le asigna la sub interfaz que se quiera, si la interfaz física es la F 0/0, entonces la sub interfaz seria la 0/0.10.
Router (config-subif) # exit

Configurar las VLANS y hacer Router on Stick

Para crear la VLAN y hacer el router on Stick, se debe configurar las interfaces tanto del router como del switch.

•Configurar Switch

Switch> enable
Switch# vlan database //Configurar la base datos de la Vlan
% Warning: It is recommended to configure VLAN from config mode, as VLAN database mode is being deprecated. Please consult user documentation for configuring VTP/VLAN in config mode.
Switch (vlan) #vlan 10 //Se crea una Vlan nueva, con nombre 10
VLAN 10 added: //Se notifica que se agrego
Name: VLAN0010
Switch (vlan) #vlan 20
VLAN 20 added:
Name: VLAN0020
Switch (vlan) #exit //escribiendo exit se aplican los cambios
APPLY completed.
Exiting....
Switch#

Luego hay que configurar la F0/1 la cual es la que la que está conectada al router.

Switch (config) #interface FastEthernet0/1
Switch (config-if) # switchport mode access // se le asigna modo trunk, y que el acceso sea incondicional.

A continuación necesitamos configurar f0/2 como un puerto de acceso para PC1 y f0/3 como un puerto de acceso para PC2:

Switch (config­if) #int f0/2 //se abre la interfaz 0/2
Switch (config­if) #switchport access vlan 10 //se le asignan la vlan 10
Switch (config­if) #switchport mode access
Switch (config­if) #int f0/3
Switch (config­if) #switchport access vlan 20
Switch (config­if) #switchport mode access
Switch (config­if) #^Z //ctrl+z para salir
Switch #
%SYS-5-CONFIG_I: Configured from console by console
Switch # wr //escribe la configuración en memoria
Building configuration...
[OK]

•Configurar el Router

El proceso es parecido al del switch, se crean las vlan, pero estas hay que asignárselas a las sub interfaces creadas previamente.

Router>enable
Router# vlan database
% Warning: It is recommended to configure VLAN from config mode, as VLAN database mode is being deprecated. Please consult user documentation for configuring VTP/VLAN in config mode.
Router (vlan) #vlan 10 //Se crea una Vlan nueva, con nombre 10
VLAN 10 added: //Se notifica que se agrego
Name: VLAN0010
Router (vlan) #vlan 20
VLAN 20 added:
Name: VLAN0020
Router (vlan) #exit //escribiendo exit se aplican los cambios
APPLY completed.
Exiting....
Router #

Ahora tenemos que activar para la interfaz del router f0/2 f0/3 y configurar sub interfaces (f0/0.10 y f0/0.20 con direcciones IP):

Router (config­if) #int f0/0.10
Router (config­subif) #encapsulation dot1q 10
Router (config­subif) #ip address 192.168.2.1 255.255.255.0
Router (config­subif) #
Router (config­subif) #int f0/0.20
Router (config­subif) #encapsulation dot1q 20
Router (config­subif) #ip address 192.168.3.1 255.255.255.0
Router (config­subif) #^Z
Router #
%SYS-5-CONFIG_I: Configured from console by console
Router #exit

Por último hay que asignarles direcciones ip a los host o PC, pero están en vez de asignarlas de forma estática, se realizan por medio del DCHP.

Configurar DHCP en Router

DHCP significa Protocolo de configuración de host dinámico. Es un protocolo que permite que un equipo conectado a una red pueda obtener su configuración (principalmente, su configuración de red) en forma dinámica (es decir, sin intervención particular). Sólo tiene que especificarle al equipo, mediante DHCP, que encuentre una dirección IP de manera independiente. El objetivo principal es simplificar la administración de la red.

Como tenemos dos Vlan, es necesario que el servicio de DHCP se configure dos veces, para que asigne direcciones ip al PC1 que tiene dirección .2.1 y PC2 que tiene .3.1

-->Ejemplo Para vlan 10

Router (config) #ip dhcp excluded-address 192.168.2.1 192.168.2.10 //Le damos un rango de ips a excluir del direccionamiento, ambos inclusivos, esto es buena práctica, ya que si se quiere agregar un DNS, o algún otro servicio de configuración, se toman esas ip que están excluidas.

Router (config) #ip dhcp pool dhcp_Vlan1 //le damos un nombre al ámbito de direccionamiento
Router (DHCP-config) #network 192.168.2.0 255.255.255.0 //le decimos el ámbito de dhcp_Blan1 en este caso
Router (DHCP-config) #default-router 192.168.2.1 //señalamos la ip que vamos a indicarle a los host como puerta de enlace

Podemos hacer ping de PC1 a PC2 para probar si está funciona.

Virtualization Systems

The issue of system virtualization is a broad topic and has a number of advantages and disadvantages involving end users and companies that implement projects using desktop virtualization, where more than a method used to reach your goal server using traditional services, to server-based applications accessible from a web browser.

There are multiple ways to virtualized systems, either by remote hosting, remote applications using virtual, a virtual dedicated Desktop on a remote host, or use local virtual applications as Java, or just use a virtual local operating system, all these ways are efficient and allow the needs of customers, the tools exist and some are quite robust as possible a level of security and confidence to use them.

Some of the drawbacks are that many of these ways of interacting with virtualization need from the network for logical operation, so a bandwidth of the network under can affect when attempting to synchronize data or perform some specific task and it is very susceptible to disconnections that can cause them to freeze. But we cannot ignore that this form of rendering services is very efficient because it allows companies to save much money on purchasing licenses or maintenance, investment in hardware that had to make a company to use different servers for the control their systems would be enormous, whereas with virtual systems this cost is much less being more feasible; these applications also have the characteristic that can function even if the network is disconnected, working locally with the client and the server machine, administer shared directories, resource consumption is lower, the response speed is higher and consumption on Bandwidth is more passive in allowing faster data transfer, also the result with the end user is much better and can easily perform their tasks.

Virtualization at all 'flavors' guarantees a reduction in system management costs and provides flexibility to cope with change. However, as fast as the mobility of IT, its biggest challenge will be to ensure that consumers will receive in their daily tasks.

802.11n standard

Wireless technologies is something that makes life easier, all electronic devices one way or another use it, we all know or have interacted with Wi-Fi technology, but recently approved IEEE 802.11n standard, which is like a WiFi stronger more scalable.

The highlight is that this very focused on providing end-user faster communication and greater distances.

One of its important features is that it promotes local wireless networks more scalable, much faster than the current, allowing systems to be adaptable and security deployments and installed today.

Among the benefits that 802.11n could find is that the bandwidth handling capabilities of channels 20 and 40 MHz transfer rates around 100-130 Mb/s and maximum rates of 600 Mb/s. Efficiency of spectrum utilization compared to other standards, using a special accommodation information in the headers of the packets. Operating range of distances around 70 meters indoor and 250 meters outdoor, introduces a concept of MIMO antennas, which helps to better manage the interference or noise that are susceptible such technologies.

With the 802.11n standard, applications such as high definition video, all that is good media will benefit by using this technology.

All these features make a wireless network as is feasible to use, and give us more weight in the balance when choosing between a wired or wireless network.

The 802.11n WiFi is far superior to their predecessors 802.11g WiFi, is only now that the systems are ready for use, that come with laptops and devices that enable the proper functioning of these systems in order to make a wireless network as common as a wired network, plus a wireless network and much more comfortable for the end user.

Whiteboard Session - Dr. Bharghavan discusses 802.11n