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EtherChannel

Configuring EtherChannel Between Catalyst 2900XL/3500XL Switches and CatOS Switches

Document ID: 14974

Updated: Sep 18, 2008

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Introduction

This sample configuration sets up an EtherChannel between a Cisco Catalyst 6500 that runs Catalyst OS (CatOS) and a Catalyst 3500XL switch. EtherChannel can be called Fast EtherChannel (FEC) or Gigabit EtherChannel (GEC). The name depends on the speed of interfaces or ports that you use to form the EtherChannel. You can use any of these switches in this scenario in order to obtain the same results:

  • Any Catalyst 4500/4000, 5500/5000, or 6500/6000 series switch that runs CatOS

  • Any of the Catalyst Layer 2 (L2) fixed configuration 2900XL or 3500XL series switches

In this document, two Fast Ethernet ports from each of the switches are bundled into an FEC. In this document, the terms "FEC", "GEC", "port channel", "channel", and "port group" all refer to EtherChannel.

Prerequisites

Requirements

Ensure that you meet these requirements before you attempt this configuration:

Components Used

The information in this document is based on these software and hardware versions:

  • Catalyst 3500XL switch (model WS-C3524-PWR-XL-EN) that runs Cisco IOS® Software Release 12.0(5)WC9

  • Catalyst 6500 switch (model 6506 with Supervisor Engine II) that runs CatOS software version 8.2.1

The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, make sure that you understand the potential impact of any command.

Conventions

Refer to Cisco Technical Tips Conventions for more information on document conventions.

Background Information

You must manually create EtherChannel because Catalyst 2900XL/3500XL switches do not support Port Aggregation Protocol (PAgP); CatOS switches support PAgP. PAgP facilitates the automatic creation of FEC and GEC. For more information on PAgP, refer to the Configuring EtherChannel section of the document Catalyst 6500 Series Software Configuration Guide, 8.7.

Create the port channel in the order of these steps:

Note: When you perform the steps in this order, you avoid possible problems with Spanning Tree Protocol (STP) that can occur during the configuration process. STP can shut down ports with the errdisable status on the Catalyst 6500 switch if you configure the CatOS switch as a channel before you configure the XL switch as a channel.

  1. Issue the set port disable module/port command on the CatOS switch.

    The command sets to disable mode the ports for use in port channeling.

  2. Create the port channel (port group) on the XL switch.

  3. Create the port channel on the CatOS switch.

    Note: Be sure to set the channel mode to "on". This setting is necessary in order to disable PAgP on the ports and to force the ports to form a channel.

  4. Issue the set port enable module/port command on the CatOS switch.

    The command reenables the ports that were disabled earlier.

Configure

In this section, you are presented with the information to configure the features described in this document.

Note: Use the Command Lookup Tool (registered customers only) to find more information on the commands used in this document.

Network Diagram

This document uses this network setup:

44-a.gif

Configurations

This document uses these configurations:

Catalyst 3524XL
Current configuration:
!
version 12.0
no service pad
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname cat3500
!
enable password mysecret

!--- This is the privileged mode password for the example.

!
!
!
!
!
ip subnet-zero
!
!
!
interface FastEthernet0/1
 port group 1

!--- The port group <group-number> command
!--- makes this interface a member of channel group 1.


!
interface FastEthernet0/2
 port group 1

!--- This interface is also a member of channel group 1.


!
interface VLAN1
 ip address 10.10.10.2 255.255.255.0

!--- This is the IP address for management.

 no ip directed-broadcast
 no ip route-cache
!
!
line con 0
 transport input none
 stopbits 1
line vty 0 4
 password mysecret

!--- This is the Telnet password for the example.

 login
line vty 5 15
 login
!
end

cat3500#

Catalyst 6506
begin
!
# ***** NON-DEFAULT CONFIGURATION *****
!
!
#time: Sun Feb 1 2004, 14:03:48
!
#version 8.2(1)
!

!--- Output suppressed.

!
#ip
set interface sc0 1 10.10.10.3/255.255.255.0 10.10.10.255

!--- This is the IP address for management.

!

!--- Output suppressed.

!
#port channel
set port channel 2/1-2 15

!--- The set port channel <module/port> command
!--- creates an EtherChannel on switches that run CatOS.
!--- The admin group (15, in this case) is not configured,
!--- but is a number that the system assigns randomly.

# default port status is enable
!
!
#module 1 : 2-port 1000BaseX Supervisor
!
#module 2 : 48-port 10/100BaseTX Ethernet
set port channel 2/1-2 mode on

!--- The set port channel <module/port> mode on command disables PAgP.
!--- The disablement forces the ports to form a channel with the XL switch
!--- that does not support PAgP.

!
#module 3 empty
!
#module 4 empty
!
#module 5 empty
!
#module 6 empty
!
#module 15 : 1-port Multilayer Switch Feature Card
!
#module 16 empty
end
cat6506> (enable)

Verify

Use this section to confirm that your configuration works properly.

The Output Interpreter Tool (registered customers only) (OIT) supports certain show commands. Use the OIT to view an analysis of show command output.

  • Check the port channel in the Catalyst 2900XL/3500XL switch:

    • show port group

    • show port group group-number

  • Check the spanning tree status in the Catalyst 2900XL/3500XL switch:

    • show spanning-tree

  • Check the port channel in the CatOS switch:

    • show port capabilities module

    • show port channel

    • show port channel module/port

    • show port channel info

  • Check the spanning tree status in the CatOS switch:

    • show spantree

    • show spantree vlan

    • show spantree module/port

Sample show Command Output

Catalyst 2900XL/3500XL Switch

  • show port group

    cat3500# show port group
    Group       Interface           Transmit Distribution
    -----   ---------------------   ---------------------
    1       FastEthernet0/1         source address
    1       FastEthernet0/2         source address
    cat3500#
  • show spanning-tree

    cat3500# show spanning-tree 
    
    Spanning tree 1 is executing the IEEE compatible Spanning Tree protocol
      Bridge Identifier has priority 32768, address 00d0.5868.f180
      Configured hello time 2, max age 20, forward delay 15
      Current root has priority 32768, address 00d0.020e.2c00
      Root port is 1, cost of root path is 12
      Topology change flag not set, detected flag not set, changes 10
      Times:  hold 1, topology change 35, notification 2
              hello 2, max age 20, forward delay 15 
      Timers: hello 0, topology change 0, notification 0
    
    Interface Fa0/1 (port 1) in Spanning tree 1 is FORWARDING
       Port path cost 12, Port priority 128
       Designated root has priority 32768, address 00d0.020e.2c00
       Designated bridge has priority 32768, address 00d0.020e.2c00
       Designated port is 33, path cost 0
       Timers: message age 2, forward delay 0, hold 0
       BPDU: sent 4, received 633
    
    Interface Fa0/3 (port 15) in Spanning tree 1 is down
       Port path cost 100, Port priority 128
       Designated root has priority 32768, address 00d0.020e.2c00
       Designated bridge has priority 32768, address 00d0.5868.f180
     
    !--- Output suppressed.
    
    

    Note: This output does not display interface Fa0/2 because the interface is bundled with Fa0/1 in the port channel. See (port 1) in the output.

Catalyst 6506 Switch

  • show port capabilities module —Use this command to check if the module supports EtherChannel.

    cat6506> (enable) show port capabilities 2
    Model                    WS-X6348-RJ-45
    Port                     2/1
    Type                     10/100BaseTX
    Speed                    auto,10,100
    Duplex                   half,full
    Trunk encap type         802.1Q,ISL
    Trunk mode               on,off,desirable,auto,nonegotiate
    Channel                  yes
    Broadcast suppression    percentage(0-100)
    Flow control             receive-(off,on),send-(off)
    Security                 yes
    Membership               static,dynamic
    Fast start               yes
    QOS scheduling           rx-(1q4t),tx-(2q2t)
    CoS rewrite              yes
    ToS rewrite              DSCP
    UDLD                     yes
    Inline power             auto,off
    AuxiliaryVlan            1..1000,1025..4094,untagged,dot1p,none
    SPAN                     source,destination
    COPS port group          2/1-48
    Link debounce timer      yes
    Dot1q-all-tagged         yes
    --------------------------------------------------------------
    Model                    WS-X6348-RJ-45
    Port                     2/2
    Type                     10/100BaseTX
    Speed                    auto,10,100
    Duplex                   half,full
    Trunk encap type         802.1Q,ISL
    Trunk mode               on,off,desirable,auto,nonegotiate
    Channel                  yes
    Broadcast suppression    percentage(0-100)
    Flow control             receive-(off,on),send-(off)
    Security                 yes
    Membership               static,dynamic
    Fast start               yes
    QOS scheduling           rx-(1q4t),TX(2q2t)
    COs rewrite              yes
    ToS rewrite              DSCP
    UDLD                     yes
    Inline power             auto,off
    AuxiliaryVlan            1..1000,1025..4094,untagged,dot1p,none
    SPAN                     source,destination
    COPS port group          2/1-48
    Link debounce timer      yes
    Dot1q-all-tagged         yes
    --------------------------------------------------------------
    
    !--- Output suppressed.
    
    
  • show port channel

    cat6506> (enable) show port channel
    Port  Status     Channel              Admin Ch
                     Mode                 Group Id
    ----- ---------- -------------------- ----- -----
     2/1  connected  on                      15  1762
     2/2  connected  on                      15  1762
    
    Port  Device-ID                       Port-ID                   Platform
    ----- ------------------------------- ------------------------- ----------------
    
     2/1  cat3500                         FastEthernet0/1           cisco WS-C3524-PWR-XL
     2/2  cat3500                         FastEthernet0/2           cisco WS-C3524-PWR-XL
    cat6506> (enable)
  • show port channel info

    cat6506> (enable) show port channel info
    Switch Frame Distribution Method: ip both
    
    Port  Status     Channel              Admin Channel Speed Duplex Vlan
                     mode                 group id
    ----- ---------- -------------------- ----- ------- ----- ------ ----
     2/1  connected  on                      15    1762 a-100 a-full    1
     2/2  connected  on                      15    1762 a-100 a-full    1
    
    Port  Channel Oper-group Neighbor   Oper-Distribution PortSecurity/
          ifIndex            Oper-group Method            Dynamic port
    ----- ------- ---------- ---------- ----------------- -------------
     2/1  67             241            ip both
     2/2  67             241            ip both
    
    Port  Device-ID                       Port-ID                   Platform
    ----- ------------------------------- ------------------------- ----------------
     2/1  cat3500                         FastEthernet0/1           cisco WS-C3524-PWR-XL
     2/2  cat3500                         FastEthernet0/2           cisco WS-C3524-PWR-XL
    
    !--- Output suppressed.
    
    
  • show spantree vlan

    cat6506> (enable) show spantree 1
    VLAN 1
    Spanning tree mode          RAPID-PVST+
    Spanning tree type          ieee
    Spanning tree enabled
    
    Designated Root             00-04-9b-bf-04-00
    Designated Root Priority    32768
    Designated Root Cost        0
    Designated Root Port        1/0
    Root Max Age   20 sec   Hello Time 2  sec   Forward Delay 15 sec
    
    Bridge ID MAC ADDR          00-04-9b-bf-04-00
    Bridge ID Priority          32768
    Bridge Max Age 20 sec   Hello Time 2  sec   Forward Delay 15 sec
    
    Port                     State         Role Cost      Prio Type
    ------------------------ ------------- ---- --------- ---- --------------------
     1/1                     not-connected  -           4   32
     1/2                     not-connected  -           4   32
    2/1-2                    forwarding    DESG        12   32 P2P, PEER(STP)
     2/3                     not-connected  -         100   32
     2/4                     not-connected  -         100   32
     2/5                     not-connected  -         100   32
     2/6                     not-connected  -         100   32
    
    !--- Output suppressed.
    
    
  • show spantree module/port

    cat6506> (enable) show spantree 2/1
    Edge Port:          No, (Configured) Default
    Link Type:         P2P, (Configured) Auto
    Port Guard:    Default
    Port                     Vlan State         Role Cost      Prio Type
    ------------------------ ---- ------------- ---- --------- ---- -----------------
    2/1-2                    1    forwarding    DESG        12   32 P2P, PEER(STP)
    cat6506> (enable)
    
    cat6506> (enable) show spantree 2/2
    Edge Port:          No, (Configured) Default
    Link Type:         P2P, (Configured) Auto
    Port Guard:    Default
    Port                     Vlan State         Role Cost      Prio Type
    ------------------------ ---- ------------- ---- --------- ---- -----------------
    2/1-2                    1    forwarding    DESG        12   32 P2P, PEER(STP)
    cat6506> (enable)

    Note: The output of the show spantree module/port command for ports 2/1 and 2/2 displays identical results because the ports are grouped together in one channel.

Troubleshoot

There is currently no specific troubleshooting information available for this configuration.

Related Information

Updated: Sep 18, 2008
Document ID: 14974