Link Aggregation EtherChannel

Presentación del tema: "Link Aggregation EtherChannel"— Transcripción de la presentación:

1 Link Aggregation EtherChannel
Gestion de Redes USC DHCP VLANs Link Aggregation EtherChannel Parte I Ing. Fernando Velez Varela

2 IP Addressing Services
Dynamic Host Configuration Protocol (DHCP)

3 Dynamic Host Configuration Protocol (DHCP)
Every device that connects to a network needs an IP address. Network administrators assign static IP addresses to routers, servers, and other network devices whose locations (physical and logical) are not likely to change. User computers in an organization often change locations, physically and logically. Desktop clients do not require a static address. A workstation can use any address within a range of addresses. This range is typically within an IP subnet.

4 Dynamic Host Configuration Protocol (DHCP)
Administrators typically prefer a network server to offer DHCP services. Scalable. Relatively easy to manage. In a small branch or SOHO location, a Cisco router can be configured to provide DHCP services without the need for an expensive dedicated server.

5 DHCP Operation Address Allocation Methods: Manual:
The IP address for the client is pre-allocated by the administrator and DHCP conveys the address to the client. Automatic: DHCP automatically assigns a permanent IP address to a client with no lease period. Dynamic: DHCP assigns, or leases, an IP address to the client for a limited period of time.

6 DHCP Operation Dynamic Allocation: DHCP works in a client/server mode.
When the client connects, the server assigns or leases an IP address to the device. The device connects to the network with that leased IP address until the lease period expires. The host must contact the DHCP server periodically to extend the lease. The leasing of addresses assures that addresses that are no longer used are returned to the address pool for use by other devices.

7 DHCP Operation Dynamic Allocation: 4 Step Process. DHCPDISCOVER:
The client broadcasts a DHCPDISCOVER message. The DHCPDISCOVER message finds the DHCP server(s) on the network.

8 DHCP Operation Dynamic Allocation: 4 Step Process. DHCPOFFER:
The server responds with a DHCPOFFER. The DHCPOFFER message is sent as a unicast and contains an available IP address to lease.

9 DHCP Operation Dynamic Allocation: 4 Step Process. DHCPREQUEST:
The client responds with a broadcast of a DHCPREQUEST message. When used for obtaining a lease, it serves as an acceptance notice to the selected server and an implicit decline to any other servers. Also used for lease renewal and verification.

10 DHCP Operation Dynamic Allocation: 4 Step Process. DHCPACK:
The server verifies the lease information and responds with a DHCPACK message. The client logs the information and sends an ARP request to verify that the address is unique.

11 DHCP Operation Dynamic Allocation: 4 Step Process.

12 BOOTP and DHCP Bootstrap Protocol (BOOTP): Predecessor of DHCP.
A method to download address and boot configurations for diskless workstations. Both DHCP and BOOTP are client/server based and use UDP ports 67 and 68. The main difference is that BOOTP was designed for manual pre-configuration of the host information in a server database.

13 Added to support functions of DHCP.
DHCP Message Format The developers of DHCP needed to maintain compatibility with BOOTP. Same as BOOTP Added to support functions of DHCP.

14 Configuring a Cisco Router as a DHCP Server
3 Basic Steps: Step 1: Define a range of addresses that DHCP is not to allocate. Usually static addresses reserved for the router interface, switch management IP address, servers, and local network printers. Step 2: Create the DHCP pool of addresses using the ip dhcp pool command. Step 3: Configure the specific DHCP tasks for the pool.

15 Configuring a Cisco Router as a DHCP Server
The DHCP service is enabled by default on versions of Cisco IOS that support it. To disable the service: Router(config)#no service dhcp To enable the service: Router(config)#service dhcp

16 Configuring a Cisco Router as a DHCP Server
Step 1: Exclude an address or addresses from the pool: Router(config)#ip dhcp excluded-address low-address [high-address] Exclude an individual address or range of addresses when assigning addresses to clients. Used to reserve addresses that are statically assigned to key hosts, for instance, the interface address on the router.

17 Configuring a Cisco Router as a DHCP Server
Step 2: Create the DHCP pool and place the router in DHCP configuration mode. Router(config)#ip dhcp pool [pool-name] Router(config-dhcp)#

18 Configuring a Cisco Router as a DHCP Server
Step 3: Configure the specific DHCP tasks. Define the pool of addresses: Router(config-dhcp)# network network-number [mask | /prefix] The network statement enables DHCP on any router interfaces belonging to that network. The router will act as a DHCP server on that interface. It is also the pool of addresses that the DHCP server will use.

19 Configuring a Cisco Router as a DHCP Server
Step 3: Configure the specific DHCP tasks. Assign the default gateway for the DHCP clients: Router(config-dhcp)# default-router ip-address [ip-address2……] Only one is required but up to 8 addresses may be assigned in one command line.

20 Configuring a Cisco Router as a DHCP Server
Step 3: Configure the specific DHCP tasks. Assign the DNS Server(s) for the DHCP clients: Router(config-dhcp)# dns-server ip-address [ip-address2……] Only one is required but up to 8 addresses may be assigned in one command line.

21 Configuring a Cisco Router as a DHCP Server
Step 3: Configure the specific DHCP tasks. Assign the WINS Server(s) for the DHCP clients: Router(config-dhcp)# netbios-name-server ip-address [ip-address2……] Only one is required but up to 8 addresses may be assigned in one command line.

22 Configuring a Cisco Router as a DHCP Server
Step 3: Configure the specific DHCP tasks. Assign the Domain Name for the DHCP clients: Router(config-dhcp)# domain-name [domain]

23 Configuring a Cisco Router as a DHCP Server
Step 3: Configure the specific DHCP tasks. Assign the duration of the lease for the DHCP clients: Router(config-dhcp)# lease {days [hours] [minutes] | infinite} The default lease time is 1 day.

24 Configuring a Cisco Router as a DHCP Server
Step 3: Configure the specific DHCP tasks. FYI - Other available parameters: Router(config-dhcp)# netbios-node-type [type] host address [mask | /prefix] hardware-address hardware-address-type or client-identifier unique-identifier client-name name bootfile filename

25 Configuring a Cisco Router as a DHCP Server
FYI By default, the DHCP server pings a pool address twice before assigning the address to a requesting client. If the ping is unanswered within 500 ms (i.e. times out), the DHCP server assumes that the address is not in use and assigns the address to the requesting client. To change the number of ping packets sent and/or the timeout wait value: Router(config)#ip dhcp ping packets number Router(config)#ip dhcp ping timeout milliseconds

26 Configuring a Cisco Router as a DHCP Server
Step 1 Step 2 Step 3

27 Configuring a Cisco Router as a DHCP Server
Verifying DHCP: Router# show ip dhcp binding show ip dhcp server statistics show ip dhcp pool debug ip dhcp server events

28 DHCP Relay In a complex hierarchical network, enterprise servers are usually contained in a server farm. These servers may provide DHCP, DNS, TFTP, and FTP services for the clients.

29 DHCP Relay Broadcast Broadcast
PC1 either tries to obtain an IP configuration or attempts to renew its address. In addition, other network services use broadcasts to find a TFTP server or an authentication server.

30 DHCP Relay Broadcast Broadcast The solution is DHCP Relay.
By configuring a helper address feature on intervening routers and switches the device will forward DHCP broadcasts, and others, to the appropriate server.

31 DHCP Relay Broadcast To configure RTA Fa0/0 (the interface that receives the Host A broadcasts) to relay DHCP broadcasts to the DHCP server, use the following commands: RTA(config)#interface fa0/0 RTA(config-if)#ip helper-address

32 DHCP Relay DHCP is not the only service that the router can be configured to relay. By default, the ip helper-address command forwards broadcasts for eight UDP services.

33 DHCP Relay Default Forwarded UDP Services Add SNMP
If you wish to stop the forwarding of a service or add another service for forwarding, it can be done using the ip forward-protocol command. Add SNMP

34 ¿Tienen alguna pregunta?
Fin de la Parte I

35 Link Aggregation EtherChannel
Gestion de Redes USC DHCP VLANs Link Aggregation EtherChannel Parte II Ing. Fernando Velez Varela

36 Objetivos Comparar los tipos de switches que se utilizan en una red empresarial. Explicar cómo el protocolo de árbol de extensión (STP) previene los bucles de conmutación. Describir y configurar las VLAN en un switch Cisco. Describir y configurar el enlace troncal y el enrutamiento entre VLAN. Actualizar las VLAN en una red empresarial.

37 Comparación de los tipos de switches que se utilizan en una red empresarial
Labor del Switch: Conmutación y segmentación de la red Memoria de contenido direccionable (CAM: Content Addressable Memory) y aging timer & aging out. Floods Broadcast & collision domains (microsegmentación) Circuitos virtuales (VCs) Switches simétricos y asimétricos

38 Comparación de los tipos de switches que se utilizan en una red empresarial
Conmutación de Capa 2 basado en el hardware Conmutación de Capa 3 basado en el software ASIC (Application-Specific Integrated Circuit)

39 Comparación de los tipos de conmutación que se utilizan en una red empresarial
Conmutación de envío y almacenamiento (Store & Forward) Envío lento: cálculo CRC con FCS Introduce latencia. Se usa en ambientes con muchos errores Conmutación por método de corte (cut-through switching) Envío rápido (fast-forward): lee MAC y reenvía Libre de fragmentos (fragment-free): lee 64B y reenvía. Evita runts Adaptive Cut-through

40 Comparación de los tipos de conmutación que se utilizan en una red empresarial
Seguridad física del switch Seguridad para acceso al switch passwords seguros, SSH, monitorización de acceso y tráfico, deshabilitar acceso web, deshabilitar puertos no usados, habilitar seguridad de puerto, deshabilitar telnet

41 Explicación sobre cómo el protocolo spanning tree (STP)previene los bucles de conmutación
Importancia de la redundancia en un equipo de red Enlaces redundantes de red Peligros de los bucles de conmutación Tormentas de broadcast Multiple frame transmissions and MAC database instability.

42 Explicación sobre cómo el protocolo spanning tree (STP) previene los bucles de conmutación
Creación de una topología lógica sin bucles Posible detección de bucle y bloqueo de puerto Redundancia sin los bucles de conmutación Bridge PDU (BPDU)

43 Explicación sobre cómo el protocolo spanning tree (STP) previene los bucles de conmutación
Estados de cada puerto al encender el switch

44 Explicación sobre cómo el protocolo spanning tree (STP) previene los bucles de conmutación
Determinación de un puente raíz (Root Bridge) ID del puente (BID) = Bridge priority + MAC El Root Bridge es el que tiene el BID más bajo Puertos raíz, puertos designados y puertos bloqueados

45 Explicación sobre cómo el protocolo spanning tree (STP) previene los bucles de conmutación
Para establecer prioridad: S3(config)#spanning-tree vlan 1 priority 4096 Para reestablecer la prioridad a su valor por defecto: S3(config)#no spanning-tree vlan 1 priority

46 Explicación sobre cómo el protocolo spanning tree (STP) previene los bucles de conmutación
Si un enlace operativo sale de servicio, STP activa un puerto bloqueado. Esto toma de 30 a 50 s por switch Minimización del tiempo de inactividad PortFast: entra en actividad saltándose los estados de escucha y aprendizaje UplinkFast: aceleración BackboneFast: aceleración usado en el backbone Propietarios de CISCO

47 Explicación sobre cómo el protocolo spanning tree (STP) previene los bucles de conmutación
Comandos para la verificación de spanning tree S1#show spanning-tree - Muestra root ID, bridge ID, y estado de puertos S1#show spanning-tree summary – Muestra un resumen del estado de puertos S1#show spanning-tree root – Muestra el estado y configuración del root bridge S1#show spanning-tree detail – Muestra información de puerto detallada S1#show spanning-tree interface – Muestra estado y configuración de las interfaces STP S1#show spanning-tree blockedports – Muestra los puertos bloqueados

48 Explicación sobre cómo el protocolo spanning tree (STP) previene los bucles de conmutación
Protocolo Rapid Spanning-Tree (RSTP) No propietario Se reconfigura en menos de 1 segundo IEEE 802.1w 3 Estados: Descarte, Aprendizaje y Transmisión Introduce el concepto de Topología activa

49 Descripción y configuración de las VLAN en un switch Cisco
LAN virtuales (VLAN’s) (Switchs de capa 2 y de capa 3) Redes lógicas diferentes de las redes físicas Ofrecen control de broadcast Transparente a usuarios finales

50 Descripción y configuración de las VLAN en un switch Cisco
Funciones VLAN (reducen los dominios de broadcast, incrementa el desempeño de la red y dan seguridad) Pertenencia a VLAN * Estática * Dinámica necesita un VMPS (VLAN Management Policy Server) No todos los switches Soportan VMPS

51 Descripción y configuración de las VLAN en un switch Cisco
VLAN 1: VLAN de administración, para accesar el switch, CDP, VTP Nombres y números de VLAN (1000 y más) Asignación de puerto, individual o por rango Comandos

52 Descripción y configuración de las VLAN en un switch Cisco
Comandos de verificación de VLAN: show vlan, show vlan brief, show vlan id vlan_number, show vlan name vlan_name. Eliminación de una VLAN: no vlan vlan_number Eliminar un puerto de una VLAN: no switchport access vlan vlan_number (estando dentro de la interface)

53 Descripción y configuración de las VLAN en un switch Cisco
Identificador de VLAN (VID), 4 Bytes Frame tagging: adición del VID a una trama ethernet Etiquetado de tramas: IEEE 802.1Q, dot1q Cambio en el tamaño del paquete: a Bytes Relación con dispositivos que no soportan 802.1Q

54 Descripción y configuración del enlace troncal y el enrutamiento entre VLAN
2 modos de puerto: access port & trunk port Características del puerto troncal Enlace punto a punto Traslada el tráfico de varias VLAN sobre un único enlace El puerto troncal soporta frame tagging Protocolo propietario de CISCO: Inter-Switch Link (ISL), poco usado

55 Descripción y configuración del enlace troncal y el enrutamiento entre VLAN
Designación de un puerto como trunk port: Switch(config)#interface fa0/port_number Switch(config-if)#switchport trunk encapsulation {dot1q | isl | negotiate} Switch(config-if)#switchport mode trunk Para que el switch detecte configuración: Switch(config-if)#switchport mode dynamic {desirable | auto} Para que el puerto vuelva a ser access mode: Switch(config-if)#no switchport mode trunk ó Switch(config-if)#switchport mode access

56 Descripción y configuración del enlace troncal y el enrutamiento entre VLAN
Las VLAN se pueden extender a través de los switches Tráfico que no usa VID: untagged (CDP, VTP, VoIP*) Untagged traffic pertenece a la VLAN nativa, que por defecto es la VLAN 1, pero se puede cambiar Switch(config-if)#dot1q native vlan vlan-id

57 Descripción y configuración del enlace troncal y el enrutamiento entre VLAN
¿Cómo lograr conectividad entre diferentes VLAN? Con un router con una interface con cada VLAN o bien mediante Subinterfaces: Router-on-a-stick

58 Descripción y configuración del enlace troncal y el enrutamiento entre VLAN
Configuración en el switch como trunk port En el router: Router(config)#interface fa0/1 Router(config-if)#no ip address Router(config-if)#no shutdown Router(config)#interface fa0/1.10 Router(config-subif)#encapsulation dot1q 10 Router(config-subif)#ip address

59 Práctica de Laboratorio

60 Actualización de la estructura VLAN en una red empresarial
El VLAN Trunking Protocol (VTP) facilita y mantiene uniforme la configuración de switches en una red. Existen Versiones 1 y 2 que no son compatibles. Dominio de administración: define quienes se comunican. Modos VTP: servidor, cliente, transparente. Base de datos de la VLAN se guarda en la NVRAM. Número de revisión de configuración (máximo 2,147,483,648) Cuidados al añadir un nuevo switch

61 Actualización de la estructura VLAN en una red empresarial
Mensajes VTP * Publicaciones de resumen: enviadas cada 5 minutos. Contienen el nombre de dominio y número de revisión. * Publicaciones de subconjunto: enviadas como respuesta a las Solicitudes de publicación. Contienen información de las VLAN. * Solicitudes de publicación: enviadas para solicitar información de las VLAN.

62 Actualización de la estructura VLAN en una red empresarial
Los switches son servers por default. Al conectar un nuevo switch realizar estos pasos: 1) Configurar VTP off-line Switch(config)#vtp domain domain_name Switch(config)#vtp mode (server – client – transparent) Switch(config)#vtp password password Switch(config)#end Switch(config)#running-config startup-config 2) Verificar la configuración VTP ) Reiniciar el switch Switch# show vtp status Switch#reload Switch#show vtp password Switch#show vtp counters

63 Actualización de la estructura VLAN en una red empresarial
Teléfonos IP y VLAN: Ancho de banda dedicado. Seguridad inalámbrica y VLAN: Aumenta la seguridad. Las mejores prácticas VLAN Seguridad VLAN

64 Resumen Los switches envían tráfico utilizando técnicas de almacenamiento y envío o por método de corte Se deberían aplicar características de seguridad básica a los switches Una VLAN es una forma de agrupar hosts en la misma red lógica incluso cuando pueden estar físicamente separados El etiquetado de las tramas permite que un switch identifique la red VLAN de origen de una trama Ethernet. Se necesita un dispositivo de Capa 3 para trasladar tráfico entre las distintas VLAN. Las subinterfaces permiten que las interfaces del router admitan varias VLAN. El protocolo de enlace troncal VLAN proporciona control centralizado, distribución y actualización de las VLAN.

65 ¿Tienen alguna pregunta?
Fin de la Parte II

66 Link Aggregation EtherChannel
Gestion de Redes USC DHCP VLANs Link Aggregation EtherChannel Parte III Ing. Fernando Velez Varela

67 Contents Objectives Link Aggregation Concepts
Link Aggregation Configuration Summary Objectives *In networks with redundancy STP helps prevent: Switching Loops Layer 2 Broadcast Storms *BID (Bridge ID) = Used to determine the Root Bridge: 1. Bridge Priority Number = (default) Lowest 2. Extended System ID = ID for VLANs 3. MAC Address = Lowest MAC Address *Port Costs: 10 Gig = 2 1 Gig = 4 100 Mb = 19 10 Mb = 100 *Port Designations: Root Port = Closest to the root bridge Designated Port = Forwarding Non-Designated Port = Blocking Explain the operation of link aggregation in a switched LAN environment. Describe EtherChannel technology. Configure link aggregation to improve performance on high-traffic switch links. Configure link aggregation with EtherChannel. Verify and troubleshoot link aggregation with EtherChannel.

68 Link Aggregation Introduction to Link Aggregation
Link aggregation allows the creation of logical links made up of several physical links. EtherChannel is a form of link aggregation used in switched networks. Introduction to Link Aggregation

69 Link Aggregation Advantages of EtherChannel
Most configurations are done on the EtherChannel interface ensuring consistency throughout links. Relies on existing switch ports – no need for upgrades. Load-balances between links on the same EtherChannnel. Creates an aggregation viewed as one logical link by STP. Provides redundancy because the overall link is viewed as one logical connection. If one physical link within channel goes down, this does not cause a change in the topology and does not require STP recalculation. Advantages of EtherChannel

70 EtherChannel Operation Implementation Restrictions
EtherChannel implemented by grouping multiple physical ports into one or more logical EtherChannel links. Interface types cannot be mixed. EtherChannel provides full-duplex bandwidth up to 800 Mb/s (Fast EtherChannel) or 8 Gb/s (Gigabit EtherChannel).  EtherChannel can consist of up to 16 compatibly-configured Ethernet ports. The Cisco IOS switch currently supports six EtherChannels. Implementation Restrictions

71 EtherChannel Operation Port Aggregation Protocol (PAgP)

72 EtherChannel Operation Link Aggregation Control Protocol (LACP)

73 Configuring EtherChannel Configuration Guidelines
EtherChannel must be supported. Speed and duplex must match. VLAN match – All interfaces are in the same VLAN. Range of VLAN  – Same range on all interfaces. Configuration Guidelines

74 Configuring EtherChannel Configuring Interfaces

75 Verifying and Troubleshooting EtherChannel Verifying EtherChannel
show interface Port-channel – Displays the general status of the EtherChannel interface. show etherchannel summary – Displays one line of information per port channel. show etherchannel port-channel – Displays information about a specific port channel interface. show interfaces etherchannel – Provides information about the role of the interface in the EtherChannel. Verifying EtherChannel

76 Verifying and Troubleshooting EtherChannel Troubleshooting EtherChannel

77 Sample CLI commands S1(config)# vlan 10 S1(config-vlan)# vlan 20 S1(config-vlan)# exit S1(config)# int f0/1 S1(config-if)# switchport mode access S1(config-if)# switchport access vlan 10 S1(config-if)# int f0/10 S1(config-if)# switchport mode access S1(config-if)# switchport access vlan 20 <repeat commands above on other switches> S1(config)# int range g0/1-2 S1(config-if)# channel-group 1 mode active ( or passive, auto, desirable, on) S1(config-if)# exit S1(config)# int port-channel 1 S1(config-if)# switchport mode trunk S1(config-if)# switchport trunk allowed vlan 10,20

78 Summary This chapter described:
EtherChannel and how to encompass both the PAgP-based and the LACP-based link aggregation methods EtherChannel technologies and the various means available to implement them The configuration, verification, and troubleshooting of EtherChannel Chapter 3 Summary

79 ¿Tienen alguna pregunta?
Fin de la Parte III

80 The Human Network: Changing the way we Work, Live, Play, and Learn.