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Tipica red empresarial con centra office y branch office

Mas detalle del cabledo utilizado

CSU/DSU hardware 2 options- outside router- integrado interface serial router

Cableado WAN en la telco y en CSU/DSU usa RJ-48 similar a RJ45

Del external CSU/DSU al router usa serial cable

Cisco Integrated ServicesRouters

Cisco ofrece devices que son routery SW + otras finciones (security VPN).Dentro de la seria de productos ISR est el cisco 1841ISR.

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Physi cal Installation

To install a router, follow these steps:

Step 1 Connect any LAN cables to the LAN ports.

Step 2 If using an external CSU/DSU, connect the routers serial interface to the

CSU/DSU, and the CSU/DSU to the line from the telco.

Step 3 If using an internal CSU/DSU, connect the routers serial interface to the line from the telco.

Step 4 Connect the routers console port to a PC (using a rollover cable), as needed, to configure the router.

Step 5 Connect a power cable from a power outlet to the power port on the router.

Step 6 Turn on the router.

A SOHO Installation with a Separate Switch, Router, and Cable Modem

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An Internet connection that uses CATV or DSL needs a device that converts between the Layer 1 and 2standards used on the CATV cable or DSL line, and the Ethernet used by the router.

These devices, commonly called cable modems andDSL modems, respectively, convert electrical signals between an Ethernet cable

and either CATV or DSL.

In fact, while the details differ greatly, the purpose of the cable modem and DSL modem is similar to a CSU/DSU on a serial link.

A CSU/DSU converts between the Layer 1 standards used on a telcos WAN circuit and a serial cables Layer 1 standardsand

routers can use serial cables.

Similarly, a cable modem converts between CATV signals and a Layer 1 (and Layer 2) standard usable by a routernamely,

Ethernet. Similarly, DSL modems convert between the DSL signals over a home telephone line and Ethernet.

steps to install this SOHO router:

Step 1 Connect a UTP straight-through cable from the router to the switch.

Step 2 Connect a UTP straight-through cable from the router to the cable modem.

Step 3 Connect the routers console port to a PC (using a rollover cable), as needed, to configure the router.

Step 4 Connect a power cable from a power outlet to the power port on the router.Step 5 Turn on the router.

A SOHO Installation with an Integrated Switch, Router, and DSL Modem

Funciones soportadas por SOHO devices:

RouterSwitchCable or DSL modemVoice AdapterWireless AP

Hardware-enabled encryption

Comparisons Between the Switch CLI and Router CLI

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features are the same on both routers and switches:

- User and Enable (privileged) mode

- Entering and exiting configuration mode, using the configure terminal, end, and exit commands,and the Ctrl-Z key sequence

- Configuration of console, Telnet, and enable secret passwords

- Configuration of SSH encryption keys and username/password login credentials

- Configuration of the host name and interface description

- Configuration of Ethernet interfaces that can negotiate speed, using the speed and duplexcommands

- Configuring an interface to be administratively disabled (shutdown) and administratively enabled(no shutdown)

- Navigation through different configuration mode contexts using commands like line console 0 andinterface

- CLI help, command editing, and command recall features

- The meaning and use of the startup-config (in NVRAM), running-config (in RAM), and externalservers (like TFTP), along with how to use the copy command to copy the configuration files andIOS images

- The process of reaching setup mode either by reloading the router with an empty startup-configor by using the setup command

work differently with the router CLI as compared to the switch CLI, namely:

- The configuration of IP addresses differs in some ways.

- The questions asked in setup mode differ.

- Routers have an auxiliary (Aux) port, intended to be connected to an external modem and phoneline, to allow remote users to dial into the router, and access the CLI, by making a phone call.

SW routerShow mac address-

table s

n (porque es

L2)

Show ip routen (porque esL3) s

shows the output of the show mac address-table dynamic command, which lists the most importanttable that a switch uses for forwarding frames. The router IOS does not support this commandinstead,routers support the show ip route command, which lists the IP routes known to the router, which of courseis the most important table that a router uses for forwarding packets

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Router Interfaces

Router types physical interfaces son 2:

Ethernet interfaces only 10Mbps => Config con interface Ethernet nro100Mbps => config con interface fasthernet nro1Gbps => config con interface gigabitethernet nro

Serial interface -para p-to-p leased line use same standart de layer 1Fram relay

-selecccionar data link layer protocol de 2 posibles - HDLC (use interface por default)- PPP

Los router usan nmeros para distinguir las interfaces

interface ethernet 0interface fastEthernet 0/1interface serial 1/0/1

Los comandos usados para ver las interfaces son:

- Show ip interface brief => brief list interface- Show protocol type nro => p interf particulares, no dispobible para todos los IOS- Show interfaces => ver statistics c/interface- Show interface type nro => p interface particular

Example 13-1

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Se puede reducir el comando a:

Sh interface fa0/0

Interface Status Co des

Siempre que line status es NO up => protocol status ser down

Router Interface IP Addresses

El router necesita IP address en c/interface

Si no se configura y aun que este up/up la interface no intentara recibir ni enviar packet eninterface

Ip address ip mask => config ip on interface router

Se ve con:- Show ip interface brief

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- Show interface fa 0/0

Bandwidth and Clock Rate on Serial Interfaces

Ethernet interfaces use either a single speed or one of a few speeds that can be auto- negotiated.

However, as mentioned in Chapter 4, WAN links can run at a wide variety of speeds. To deal with the wide range of speeds,

routers physically slave themselves to the speed as dictated by the CSU/DSU through a process called clocking.

As a result, routers can use serial links without the need for additional configuration or autonegotiation to sense the serial linksspeed. The CSU/DSU knows the speed, the CSU/DSU sends clock pulses over the cable to the router, and the router reacts to the

clocking signal. In effect, the CSU/DSU tells the router when to send the next bit over the cable, and when to receive the next bit,

with the router just blindly reacting to the CSU/DSU for that timing.

The physical details of how clocking works prevent routers from sensing and measuring the speed used on alink with CSU/DSUs

En LAB no se usa CSU/DSU => q el cloking lo da un router q usa back-to-back serial cablesEl otro router q normalmente usa CSU/DSU graba el cloaking recibido del otro router,

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IOS acepta el comando clock rate si tiene instalado el cable DCE, si usa DTE rechaza el comando.

Bandwith (kbps)

Dice la speed de la lnea- No cambia la speed de los bits en el link- Router lo usa para calculo de utilization rate del link, p EIGRP y OSPF en calculo de la

mtrica.

Sino esta configurado el valor por default es 1544kbps

Router Auxiliary (Aux) Port

- P acceder al CLI por emulador de terminal- Usa RJ45 a external modem y phone line- Se configura con line aux 0- Los SW NO tienen Aux Port

Initial Configur ation (Setup Mode)

Los siguientes son true en ambos SW y Router:

Setup mode is intended to allow basic configuration by prompting the CLI user via a series of questions.

You can reach setup mode either by booting a router after erasing the startup-config file or by using the setup enable-mode

EXEC command.

At the end of the process, you get three choices (0, 1, or 2), to either ignore the answers and go back to the CLI (0); ignore

the answers but begin again in setup mode (1);

or to use the resulting configuration (2).

If you tire of the process, the Ctrl-C key combination will eject the user out of setup mode and back to the previous CLImode.

If you select to use the resulting configuration, the router writes the configuration to the startup-config file, as well as the

running-config file.

Diferencias:

- El SW config solo 1 IP mientras el router usa p/c interface

Ver ejemplo 13-4 (P418)

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Upgrading a Cisco IOS Software Image into Flash Memo ry

Router y SW tpicamente store IOS image in Flash memory (optional TFTP Server)

Figure 13-6 illustrates the process to upgrade an IOS image into Flash memory:

Step 1 Obtain the IOS image from Cisco, typically by downloading the IOS image from

Cisco.com using HTTP or FTP.

Step 2 Place the IOS image into the default directory of a TFTP server that is accessible from the router.

Step 3 Issue the copy command from the router, copying the file into Flash memory.

During this process of copying the IOS image into Flash memory, the router needs to discover

several important facts:

1. What is the IP address or host name of the TFTP server?

2. What is the name of the file?

3. Is space available for this file in Flash memory?

4. Does the server actually have a file by that name?

5. Do you want the router to erase the old files?

Donde pregunta el punto 3

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Afterward, the router erases Flash memory if directed, copies the file, and then verifies that the checksumfor the file shows that no errors occurred in transmission.

You can then use the show flash command to verify the contents of Flash memory, as demonstrated inExample 13-6. (The show flash output can vary among router families. Example 13-6 is output from a 2500series router.)

The shaded line in Example 13-6 lists the amount of Flash memory, the amount used, and the amount offree space.

Si no hay espacio en la flash el comando de copia puede fallar.

When copying a new IOS image into Flash, the copy command will ask you if you want to erase Flash, witha default answer of [yes]. If you reply with an answer ofno, and IOS realizes that not enough availableFlash memory exists, the copy will fail. Additionally, even if you answer yes, and erase all of Flashmemory, the new Flash IOS image must be of a size that fits into flash memory; if not, the copy commandwill fail.

Es necesario reiniciar para que carge la nueva versin de IOS

Once the new IOS has been copied into Flash, the router must be reloaded to use the new IOS image. The next section, which covers

the IOS boot sequence, explains the details of how to configure a router so that it loads the right IOS image.

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The Cisco IOS Software Boot Sequen ce

a router can have multiple IOS images available both in Flash memory and on external TFTP servers, sothe router needs to know which IOS image to load

Se pone nfasis en configuration register y ROMMON OS que son solo para el router, no se veequivalentes en el SW.