EtherChannel e entroncamento entre os Switches de Camada 2 Catalyst e o Exemplo de Configuração dos Switches 2948G-L3/4908G-L3

Introduction

Este documento descreve a instalação de um EtherChannel e de um entroncamento 802.1Q entre os switches Catalyst 2950 e Catalyst 2948G-L3. O EtherChannel pode ser chamado de Fast EtherChannel (FEC) ou Gigabit EtherChannel (GEC), dependendo da velocidade das interfaces e portas usadas para criá-lo.

Observação: o switch Catalyst 2950 suporta somente truncamento 802.1Q e não suporta entroncamento ISL (Inter-Switch Link Protocol). Os switches Catalyst 2948G-L3 e Catalyst 4908G-L3 compartilham a mesma imagem de software, de modo que a configuração do Catalyst 2948G-L3 usada neste documento também se aplica ao switch Catalyst 4908G-L3.

Neste exemplo de configuração, duas interfaces Fast Ethernet em um switch Catalyst 2950 são agrupadas em uma FEC com duas interfaces Fast Ethernet de um switch Catalyst 2948G-L3. FEC, GEC, canal de porta e grupo de canais se refere ao EtherChannel neste documento.

Antes de Começar

Conventions

Para obter mais informações sobre convenções de documento, consulte as Convenções de dicas técnicas Cisco.

Prerequisites

Este documento descreve a configuração de exemplo dos switches e a saída dos comandos show relacionados. Para obter detalhes e advertências ou diretrizes específicas sobre switches individuais, consulte os seguintes documentos:

• Switch Catalyst 2950 Configurando EtherChannel

• Switch Catalyst 2950 configurando troncos de VLAN

• Switch Catalyst 2948G-L3 Configurando EtherChannel

• Switch Catalyst 2948G-L3 Configurando o encapsulamento de VLAN

Componentes Utilizados

As informações neste documento são baseadas nas versões de software e hardware abaixo.

• Switch Catalyst 2948G-L3 executando Cisco IOS® Software 12.0(14)W5(20)

• Switch Catalyst 2950 executando Cisco IOS Software 12.1(12c)EA1

As informações neste documento foram criadas a partir de dispositivos em um ambiente de laboratório específico. All of the devices used in this document started with a cleared (default) configuration. Se você estiver trabalhando em uma rede ativa, certifique-se de que entende o impacto potencial de qualquer comando antes de utilizá-lo.

Material de Suporte

Do ponto de vista da configuração, o switch Catalyst 2948G-L3 é um roteador. Ele usa uma linha de comando do Cisco IOS e, por padrão, todas as interfaces são interfaces roteadas.

O switch Catalyst 2948G-L3 não estende suas VLANs por padrão. Como todas as interfaces são interfaces roteadas, cada interface deve pertencer a uma rede ou sub-rede diferente. Se você deseja que duas ou mais interfaces pertençam à mesma sub-rede, o bridging precisa ser configurado nessas interfaces.

O switch Catalyst 2948G-L3 não suporta protocolos de negociação encontrados em outros switches Catalyst, como o VLAN Trunk Protocol (VTP), Dynamic Trunking Protocol (DTP) e Port Aggression Protocol (PAgP). Recomenda-se que esses protocolos sejam desligados nas interfaces do Catalyst 2950 que se conectam ao switch Catalyst 2948G-L3.

No switch Catalyst 2948G-L3, todo o tráfego recebido na VLAN nativa em um tronco é roteado no software. Isso significa que esse tráfego é enviado à CPU. Quando uma grande quantidade de tráfego é enviada nesta VLAN, ela pode resultar em uma alta carga de CPU no switch Catalyst 2948G-L3 e ter um efeito adverso no desempenho da rede. Recomenda-se criar uma VLAN fictícia (como a VLAN 99) que possa se tornar a VLAN nativa do tronco. Todo o tráfego do usuário é enviado sobre as outras VLANs e são roteados em hardware, o que leva a um melhor desempenho.

Configurar

Nesta seção, você encontrará informações para configurar os recursos descritos neste documento.

Observação: para encontrar informações adicionais sobre os comandos usados neste documento, use a ferramenta Command Lookup Tool (somente clientes registrados).

Criando um canal de portas

Ao configurar o EtherChannel, é recomendável criar um canal de porta seguindo as etapas abaixo. Isso evitará possíveis problemas com o Spanning-Tree Protocol (STP) durante o processo de configuração. Um loop STP pode ocorrer se um lado estiver configurado como um canal antes que o outro lado esteja configurado como um canal. Como resultado, o switch pode colocar as interfaces envolvidas no loop no status Errordisabled. As etapas a seguir são diretrizes para este cenário de configuração específico.

No switch Catalyst 2948G-L3:

1. Configure as interfaces a serem usadas na canalização de portas no modo desligado administrativamente.

2. Crie o canal da porta (grupo de canais). O canal de porta transporta VLANs diferentes, portanto, crie uma subinterface para cada VLAN presente no tronco. Em um tronco 802.1Q, todos os pacotes que passam pelo tronco são marcados, exceto o tráfego na VLAN nativa. Por causa disso, você precisa distinguir a subinterface correspondente à VLAN nativa colocando a palavra-chave "nativa" no final. Como mencionado anteriormente, é melhor usar uma VLAN fictícia que não tenha tráfego de usuário.

3. O switch Catalyst 2948G-L3 tem, por padrão, todas as portas roteadas. Para que as portas em 2948G-L3 possam se comunicar em diferentes VLANs no 2950, é necessário implementar o bridging. As interfaces (e subinterfaces) que pertencem à mesma VLAN (rede ou sub-rede) devem ser configuradas para pertencer ao mesmo grupo de bridge. Para rotear entre esses diferentes grupos de bridge, o Integrated Routing and Bridging (IRB) deve estar ativado.

No switch Catalyst 2950:

1. Configure as interfaces que pertencerão ao canal como um tronco e verifique se o DTP está desligado. Isso é feito emitindo o comando switchport nonegotiate nas interfaces físicas. Configure uma VLAN fictícia (VLAN 99 neste exemplo) no banco de dados de VLAN que será usado como a VLAN nativa no tronco. A menos que especificado de outra forma, a VLAN nativa em um tronco 802.1Q é a VLAN 1. Você precisa especificar em ambas as interfaces que está usando a VLAN 99 como a VLAN nativa. Isso é feito emitindo o comando switchport trunk native vlan 99.

2. Crie o canal de porta e certifique-se de definir o modo de canal como ligado (isso desliga o PAgP).

3. Reative as interfaces que foram desativadas anteriormente no switch Catalyst 2948G-L3 emitindo o comando no shut.

Diagrama de Rede

Este documento utiliza a instalação de rede mostrada no diagrama abaixo.

Configurações

Este documento utiliza as configurações mostradas abaixo.

• Catalyst 2948G-L3

• Catalyst 2950

2948G-L3#show run 


!--- The following configuration shows how to configure Catalyst 2948G-L3 !--- for bridging and connect to a Catalyst 2950 with 802.1Q trunking !--- over EtherChannel. For configuring interVLAN-routing on Catalyst !--- 2948G-L3, refer to Catalyst 2948G-L3 Sample Configurations.
 

Building configuration... 

Current configuration: 
! 
! 
version 12.0 
no service pad 
service timestamps debug uptime 
service timestamps log datetime 
no service password-encryption 
! 
hostname 2948G-L3 
! 
! 
ip subnet-zero 
! 

!--- Enable IRB when routing between different !--- bridge groups is needed.
 
bridge irb 
! 

!--- Configure a logical interface for the EtherChannel.

interface Port-channel1 
no ip address 
no ip directed-broadcast 
hold-queue 300 in 
! 

!--- Create a subinterface for each VLAN on the port channel.
 
!
interface Port-channel1.1

!--- Specify the encapsulation and VLAN number.

 encapsulation dot1Q 1
 no ip redirects
 no ip directed-broadcast

!--- Add the subinterface to the appropriate bridge group. !--- All the interfaces (and subinterfaces) that belong to the !--- same VLAN (network or subnet) should be configured to fall !--- in the same bridge group.
 
 bridge-group 1
!

!--- Configure a subinterface for the second VLAN. !--- This procedure must be repeated for every VLAN. 

! 
interface Port-channel1.2
 encapsulation dot1Q 2
 no ip redirects
 no ip directed-broadcast
 bridge-group 2
!

!--- Configure a subinterface for the native VLAN.
 
!
interface Port-channel1.99
 encapsulation dot1Q 99 native
 no ip redirects
 no ip directed-broadcast

!--- Note in this case you do not put any bridge group !--- statements under this subinterface. A dummy VLAN has been chosen !--- as the native VLAN on which you do not put any traffic, !--- so there is no need to have this routed.
 

!
interface FastEthernet1
 no ip address
 no ip directed-broadcast

!--- Configure the port to channel 1.
 
 channel-group 1
!
interface FastEthernet2
 no ip address
 no ip directed-broadcast

!--- Configure the port to channel 1.
 
 channel-group 1
!
interface FastEthernet3
 no ip address
 no ip directed-broadcast

!--- The device connected on this interface belongs !--- to the same subnet (VLAN 1) as subinterface 1 on !--- the port channel, so this interface has to be added to !--- bridge-group 1.



 bridge-group 1
!

!--- If there are any other interfaces that belong to !--- the same VLAN (subnet), they all have to be added to !--- the respective bridge group.

( .... Output is suppressed) 
!
!
! a routed interface for bridge-group 1 
interface BVI1
 ip address 1.1.1.1 255.255.255.0
 no ip directed-broadcast
 no ip route-cache cef
!
! a routed interface for bridge-group 2
interface BVI2
 ip address 2.2.2.1 255.255.255.0
 no ip directed-broadcast
 no ip route-cache cef
!
ip classless
!
! bridge 1 protocol ieee command enables bridging using the IEEE 802.1d spanning-tree 
bridge 1 protocol ieee
! The bridge 1 route ip command specifies that IP will be routed
 bridge 1 route ip
! bridge 2 protocol ieee command enables bridging using the IEEE 802.1d spanning-tree 
 bridge 2 protocol ieee
! bridge 2 route ip command specifies that IP will be routed
 bridge 2 route ip
!
line con 0
 transport input none
line aux 0
line vty 0 4
 login
!
end

5-2950-24##show run
Building configuration...

Current configuration : 1986 bytes
!
version 12.1
no service single-slot-reload-enable
no service pad
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname 5-2950-24#
!
!
!

!--- VLAN 2 is created for this lab set up, !--- and VLAN 1 is created by default.

vlan 2
ip subnet-zero

!--- For information on VTP, refer to !--- Understanding and Configuring VLAN Trunk Protocol (VTP) 

vtp domain cisco
vtp mode transparent
!
spanning-tree extend system-id
!

!--- A logical port-channel interface is automatically created !--- when ports are grouped into a channel group.
 

!
interface Port-channel1

!--- The switchport trunk native vlan 99 command is !--- issued on the Fast Ethernet interface.

switchport trunk native vlan 99

!--- The switchport mode trunk command is !--- issued on the Fast Ethernet interface.
 
 switchport mode trunk

!-- The switchport nonegotiate command is !--- issued on the Fast Ethernet interface.

 switchport nonegotiate
 no ip address
 flowcontrol send off
!
interface FastEthernet0/1

!--- Configure the port to be in trunking mode.
 
 switchport mode trunk

!--- Configure a dummy VLAN as the native VLAN. !--- For this example, VLAN 99 is used.

 switchport trunk native vlan 99

!--- Disable the DTP negotiation on this interface !--- (the Catalyst 2948G-L3 switch does not support these frames).
 
 switchport nonegotiate
 no ip address

!--- Configure the port to channel without PAgP.
 
 channel-group 1 mode on
!
interface FastEthernet0/2

!--- Configure the port to be in trunking mode.
 
 switchport mode trunk

!--- Configure a dummy VLAN as the native VLAN. !--- For this example, VLAN 99 is used.

 switchport trunk native vlan 99

!--- Disable the DTP negotiation on this interface !--- (the Catalyst 2948G-L3 switch does not support these frames).
 
 switchport nonegotiate
 no ip address

!--- Configure the port to channel without PAgP.
 
 channel-group 1 mode on
!
interface FastEthernet0/3

!--- The PC2 on this interface belongs to VLAN 2.

 switchport access vlan 2
 switchport mode access

 no ip address

!--- On the userports, enable portfast to increase !--- the STP convergence time.
 
 spanning-tree portfast
!
( .... Output is suppressed) 
!
interface Vlan1
 ip address 1.1.1.2 255.255.255.0
 no ip route-cache

!
ip http server
!
!
line con 0
line vty 5 15
!
end

Verificar

Esta seção fornece informações que você pode usar para confirmar se suas configurações estão funcionando corretamente.

A Output Interpreter Tool (somente clientes registrados) oferece suporte a determinados comandos show, o que permite exibir uma análise da saída do comando show.

Comandos show para o Catalyst 2950

Os seguintes comandos show verificam a configuração para o switch Catalyst 2950, como mostrado na saída abaixo.

5-2950-24##show vlan

VLAN Name                             Status    Ports
---- -------------------------------- --------- -------------------------------
1    default                          active    Fa0/4, Fa0/5, Fa0/6, Fa0/7
                                                Fa0/8, Fa0/9, Fa0/10, Fa0/11
                                                Fa0/12, Fa0/13, Fa0/14, Fa0/15
                                                Fa0/16, Fa0/17, Fa0/18, Fa0/19
                                                Fa0/20, Fa0/21, Fa0/22, Fa0/23
                                                Fa0/24, Gi0/1, Gi0/2
2    VLAN0002                         active    Fa0/3
1002 fddi-default                     active    
1003 token-ring-default               active    
1004 fddinet-default                  active    
1005 trnet-default                    active    

VLAN Type  SAID       MTU   Parent RingNo BridgeNo Stp  BrdgMode Trans1 Trans2
---- ----- ---------- ----- ------ ------ -------- ---- -------- ------ ------
1    enet  100001     1500  -      -      -        -    -        0      0   
2    enet  100002     1500  -      -      -        -    -        0      0   
1002 fddi  101002     1500  -      -      -        -    -        0      0   
1003 tr    101003     1500  -      -      -        -    -        0      0   
1004 fdnet 101004     1500  -      -      -        ieee -        0      0   
1005 trnet 101005     1500  -      -      -        ibm  -        0      0   
          
Remote SPAN VLANs
------------------------------------------------------------------------------


Primary Secondary Type              Ports
------- --------- ----------------- ------------------------------------------


5-2950-24##show interfaces port-channel 1 trunk 

Port      Mode         Encapsulation  Status        Native vlan
Po1       on           802.1q         trunking      99

Port      Vlans allowed on trunk
Po1       1-4094

Port      Vlans allowed and active in management domain
Po1       1-2

Port      Vlans in spanning tree forwarding state and not pruned
Po1       1-2


5-2950-24##show interface port-channel 1 
Port-channel1 is up, line protocol is up 
  Hardware is EtherChannel, address is 0005.7428.0e02 (bia 0005.7428.0e02)
  MTU 1500 bytes, BW 200000 Kbit, DLY 1000 usec, 
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation ARPA, loopback not set
  Full-duplex, 100Mb/s
  input flow-control is off, output flow-control is off
  Members in this channel: Fa0/1 Fa0/2 
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input 00:00:01, output 00:00:00, output hang never
  Last clearing of "show interface" counters never
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
  Queueing strategy: fifo
  Output queue :0/40 (size/max)
  5 minute input rate 25000 bits/sec, 39 packets/sec
  5 minute output rate 39000 bits/sec, 59 packets/sec
     11609 packets input, 955786 bytes, 0 no buffer
     Received 11590 broadcasts, 0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     0 watchdog, 11583 multicast, 0 pause input
     0 input packets with dribble condition detected
     17396 packets output, 1442093 bytes, 0 underruns
     0 output errors, 0 collisions, 1 interface resets
     0 babbles, 0 late collision, 0 deferred
     0 lost carrier, 0 no carrier, 0 PAUSE output
     0 output buffer failures, 0 output buffers swapped out


5-2950-24##show interface port-channel 1 switchport 
Name: Po1
Switchport: Enabled
Administrative Mode: trunk
Operational Mode: trunk
Administrative Trunking Encapsulation: dot1q
Operational Trunking Encapsulation: dot1q
Negotiation of Trunking: Off
Access Mode VLAN: 1 (default)
Trunking Native Mode VLAN: 99 (Inactive)
Administrative private-vlan host-association: none 
Administrative private-vlan mapping: none 
Operational private-vlan: none 
Trunking VLANs Enabled: ALL
Pruning VLANs Enabled: 2-1001

Protected: false

Voice VLAN: none (Inactive)
Appliance trust: none


5-2950-24##show cdp neighbors 
Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge
                  S - Switch, H - Host, I - IGMP, r - Repeater


Device ID        Local Intrfce     Holdtme    Capability  Platform  Port ID
5-2948G-L3       Fas 0/1            144         R T       Cat2948G  Port-channe1
5-2948G-L3       Fas 0/2            178         R T       Cat2948G  Fas 2
5-2948G-L3       Fas 0/1            178         R T       Cat2948G  Fas 1


PC2#ping 1.1.1.3

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 1.1.1.3, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 4/4/4 ms

Comandos show para o Catalyst 2948G-L3

Os seguintes comandos show verificam a configuração para o switch Catalyst 2948-L3, como mostrado na saída abaixo.

5-2948G-L3#show interfaces port-channel 1 
Port-channel1 is up, line protocol is up 
  Hardware is FEChannel, address is 0001.43ff.1407 (bia 0000.0000.0000)
  MTU 1500 bytes, BW 200000 Kbit, DLY 100 usec, rely 255/255, load 1/255
  Encapsulation ARPA, loopback not set, keepalive set (10 sec)
  Half-duplex, Unknown Speed, Media type unknown
  ARP type: ARPA, ARP Timeout 04:00:00
    No. of active members in this channel: 2 
        Member 0 : FastEthernet1 
        Member 1 : FastEthernet2 
  Last input 00:00:00, output 00:00:00, output hang never
  Last clearing of "show interface" counters never
  Queueing strategy: fifo
  Output queue 0/40, 0 drops; input queue 0/300, 0 drops
  5 minute input rate 2000 bits/sec, 4 packets/sec
  5 minute output rate 1000 bits/sec, 1 packets/sec
     27033 packets input, 2083710 bytes, 0 no buffer
     Received 6194 broadcasts, 0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
     0 watchdog, 0 multicast
     0 input packets with dribble condition detected
     12808 packets output, 1945983 bytes, 0 underruns
     0 output errors, 0 collisions, 0 interface resets
     0 babbles, 0 late collision, 0 deferred
     0 lost carrier, 0 no carrier
     0 output buffer failures, 0 output buffers swapped out


5-2948G-L3#show vlan

Virtual LAN ID:  1 (IEEE 802.1Q Encapsulation)

   vLAN Trunk Interfaces:  GigabitEthernet49
GigabitEthernet50.1
Port-channel1.1

 This is configured as native Vlan for the following interface(s) :
GigabitEthernet49
GigabitEthernet50

   Protocols Configured:   Address:              Received:        Transmitted:
           IP              10.10.10.1                   0                   0
        Bridging        Bridge Group 1               3418                   5

Virtual LAN ID:  2 (IEEE 802.1Q Encapsulation)

   vLAN Trunk Interfaces:  GigabitEthernet50.2
Port-channel1.2

   Protocols Configured:   Address:              Received:        Transmitted:
           IP              20.20.20.1                   0                   0
        Bridging        Bridge Group 2               3952                   9
          
Virtual LAN ID:  21 (IEEE 802.1Q Encapsulation)

   vLAN Trunk Interface:   GigabitEthernet49.1

   Protocols Configured:   Address:              Received:        Transmitted:

Virtual LAN ID:  99 (IEEE 802.1Q Encapsulation)

   vLAN Trunk Interface:   Port-channel1.99

 This is configured as native Vlan for the following interface(s) :
Port-channel1

   Protocols Configured:   Address:              Received:        Transmitted:


5-2948G-L3#show spanning-tree 

 Bridge group 1 is executing the IEEE compatible Spanning Tree protocol
  Bridge Identifier has priority 32768, address 0001.43ff.1409
  Configured hello time 2, max age 20, forward delay 15
  We are the root of the spanning tree
  Topology change flag not set, detected flag not set
  Times:  hold 1, topology change 35, notification 2
          hello 2, max age 20, forward delay 15 
  Timers: hello 0, topology change 0, notification 0
  bridge aging time 300

Port 6 (FastEthernet3) of Bridge group 1 is forwarding
   Port path cost 19, Port priority 128
   Designated root has priority 32768, address 0001.43ff.1409
   Designated bridge has priority 32768, address 0001.43ff.1409
   Designated port is 6, path cost 0
   Timers: message age 0, forward delay 0, hold 0
   BPDU: sent 4107, received 2

Port 58 (Port-channel1.1 DOT1Q) of Bridge group 1 is forwarding
   Port path cost 12, Port priority 128
   Designated root has priority 32768, address 0001.43ff.1409
   Designated bridge has priority 32768, address 0001.43ff.1409
   Designated port is 58, path cost 0
   Timers: message age 0, forward delay 0, hold 0
   BPDU: sent 5240, received 502

          
 Bridge group 2 is executing the IEEE compatible Spanning Tree protocol
  Bridge Identifier has priority 32768, address 0000.0c00.d08c
  Configured hello time 2, max age 20, forward delay 15
  Current root has priority 0, address 0010.0db1.804f
  Root port is 59 (Port-channel1.2), cost of root path is 50
  Topology change flag not set, detected flag not set
  Times:  hold 1, topology change 35, notification 2
          hello 2, max age 20, forward delay 15 
  Timers: hello 0, topology change 0, notification 0
  bridge aging time 300

Port 59 (Port-channel1.2 DOT1Q) of Bridge group 2 is forwarding
   Port path cost 12, Port priority 128
   Designated root has priority 0, address 0010.0db1.804f
   Designated bridge has priority 32770, address 0005.7428.0e00
   Designated port is 65, path cost 38
   Timers: message age 3, forward delay 0, hold 0
   BPDU: sent 1790, received 3964


PC1#ping 2.2.2.2

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 2.2.2.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 4/4/4 ms

Troubleshoot

Atualmente, não existem informações disponíveis específicas sobre Troubleshooting para esta configuração.

Informações Relacionadas

• Entendendo e configurando o protocolo VLAN Trunk (VTP)
• Exemplo de Configurações de Catalyst 2948G-L3
• Suporte ao Produto - Switches
• Suporte de tecnologia de switching de LAN
• Suporte Técnico e Documentação - Cisco Systems