HUB

Generalidades

HUB

Son dispositivos de capa1

Sólo regeneran la señal

Y la envían mediante broadcast a todos los puertos

HUB

Es un dispositivo de Networking

Networking significa interconexión de estaciones de trabajo, periféricos, terminales y otros dispositivos

HUB

Características

HUB

Llamado también ConcentradorRepresenta el centro de red en

topología estrellaSiendo el Puerto la interfaz de un

dispositivo de red:Es un Repetidor Multipuerto

HUB

Funciones

HUB

Amplifica las señalesLas propaga por la redNo filtraNo determina o conmuta rutasSe lo utiliza como punto de

concentración de la red

HUB

Una Clasificación

HUB

ActivosRepiten señales enviadas a través de

ellos

PasivosNo repiten, sino que meramente dividen

las señales enviadas a través de ellos.

HUB

Otra Clasificación

HUB

InteligentesTienen puertos de consolaSe pueden programar para

administrar el tráfico de la red

No inteligentesSin capacidad de realizar ninguna

administración

HUB

Aplicaciones

Aplicacoines

Con el propósito de aumentar el número de puertos, pueden conectarse

en cascada (hubs autónomos)

en pila (hubs conectables en pila)

Autónomos o en pila?

AutónomosPequeños grupos de trabajo4 ó 5 puertos

En pilaPermiten expansión modular

HUBS CISCO

Algunos modelos

Cisco 1538 Series — Micro Hubs 10/100

Table 13-4: Physical and Environmental Specifications for Cisco 1538 Series

Description Specification

Dimensions (H xW x D)

3.1 x 11.2 x 8.7 in. (7.85 x 28.4 x 22.1 cm); heightincludes stacking curves on top of switch

Weight 3.0 lb (1.4 kg)

Operatingtemperature

32 to 104°F (0 to 40°C)

Operatinghumidity

10 to 85% noncondensing

Operatingaltitude

up to 9840 ft (3000 m)

Storagetemperature

-40 to 149°F (-25 to 65°C)

Storage altitude 30,000 ft (9146 m)

Stack Cisco Micro Hubs to Create Larger Managed Networks

Connect Up to Eight Workstations to the Cisco Micro Hub

Modos de configuración

Existen dos:

guest mode

administrator mode (also called privileged mode). The commands available in guest mode are a subset of those available in administrator mode.

Pasaje entre modos

Qué comando escribimos:

Hub> Hub> enable

Password: ******

Hub#

Comandos de Configuración

Syntax: show hub information [hub id]

Hub> show hub informationHub ID Type H/W ver F/W ver SNMP-Agent-----------------------------------------1 1503 1.0 1.01 Yes2 1502 1.0 1.01 No3 1503 1.0 1.01 No

Command Display Definitions Hub ID--Number used to identify the hub in a stack. An

integer between 1 and 5. Read the section "Hub IDNumbers" earlier in this chapter for information abouthow to determine hub ID numbers.

Type--Model number of the hub: 1502 or 1503.

H/W ver--Hub's hardware version.

F/W ver--Hub's firmware version.

Agent--Whether or not the hub contains an active SNMP agent.

Comandos estadísticos

Syntax: show system statistics Hub> show system statisticsFrames : 9755Bytes : 78040Collisions : 671Alignment errors : 45CRC errors : 33Total errors : 867

Command Display Definitions Frames--Number of frames (packets) passing through the

hub.

Bytes--Number of bytes passing through the hub.

Collisions--Number of times that network devices attached to any one of the hubs inthe stack have attempted to send data simultaneously.

Alignment errors--Number of mis-synchronized data packets.

CRC errors--Number of cyclic redundancy check (CRC) errors.

Total errors--Total number of errors of the following types: frame control sequence,alignment, frames-too-long, short events, late events, jabber, and data rate mismatches

Syntax: show hub statistics [hub id] Hub> show hub statistics 1 Alignment CRC TotalHub ID Frames Bytes Collisions Errors Errors Errors--------------------------------------------------------------1 1039 29354 264 23 12 486

Command Display Definitions Hub ID--Position of the hub in the stack, from top to

bottom.

Frames--Number of frames (packets) passing through the hub.

Bytes--Number of bytes passing through the hub.

Collisions--Number of times that network devices attached to any one of the hubs inthe stack have attempted to send data simultaneously.

Alignment errors--Number of mis-synchronized data packets.

CRC errors--Number of CRC errors.

Total errors--Total number of errors, including the following types: frame control sequence,alignment, frames-too-long, short events, late events, jabber, and data rate mismatches.