2.9 Configure, verify, and troubleshoot (Layer 2/Layer 3) EtherChannel

Screenshot_2018-06-03_19-49-24

2.9.a Static

To configure static ether channels use the “mode on” option. Then configure the port range and the port channel interface with the “no switchport” option.

Switch>en
Switch#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
Switch(config)#^Z
%SYS-5-CONFIG_I: Configured from console by console
Switch#show spanning-tree 
VLAN0001
  Spanning tree enabled protocol ieee
  Root ID    Priority    32769
             Address     0001.C707.7E59
             Cost        19
             Port        1(FastEthernet0/1)
             Hello Time  2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    32769  (priority 32768 sys-id-ext 1)
             Address     0090.2B11.53A2
             Hello Time  2 sec  Max Age 20 sec  Forward Delay 15 sec
             Aging Time  20

Interface        Role Sts Cost      Prio.Nbr Type
---------------- ---- --- --------- -------- --------------------------------
Fa0/1            Root FWD 19        128.1    P2p
Fa0/2            Altn BLK 19        128.2    P2p
Fa0/3            Altn BLK 19        128.3    P2p
Fa0/4            Altn BLK 19        128.4    P2p
Switch(config)#int ran f0/1-4
Switch(config-if-range)#no switchport 
Switch(config-if-range)#
%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/1, changed state to down

%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/1, changed state to up

%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/2, changed state to down

%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/2, changed state to up

%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/3, changed state to down

%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/3, changed state to up

%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/4, changed state to down

%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/4, changed state to up

Switch(config-if-range)#channel-group 1 mode on
Switch(config-if-range)#
Creating a port-channel interface Port-channel 1

%LINK-5-CHANGED: Interface Port-channel1, changed state to up

%LINEPROTO-5-UPDOWN: Line protocol on Interface Port-channel1, changed state to up

Switch(config-if-range)#int port-channel 1
Switch(config-if)#ip address 10.0.0.1 255.255.255.0
Switch(config-if)#no shutdown
Switch(config-if)#^Z

2.9.b PAGP

To enable PAGP just specify the following option:

Switch(config-if-range)#channel-group 1 mode ?
  active     Enable LACP unconditionally
  auto       Enable PAgP only if a PAgP device is detected
  desirable  Enable PAgP unconditionally
  on         Enable Etherchannel only
  passive    Enable LACP only if a LACP device is detected
Switch(config-if-range)#channel-group 1 mode

2.9.c LACP

To enable LACP just specify the options:

Switch(config-if-range)#channel-group 1 mode ?
  active     Enable LACP unconditionally
  auto       Enable PAgP only if a PAgP device is detected
  desirable  Enable PAgP unconditionally
  on         Enable Etherchannel only
  passive    Enable LACP only if a LACP device is detected
Switch(config-if-range)#channel-group 1 mode

To troubleshoot and verify the configuration use the various “show” commands:

Switch#show etherchannel summary 
Flags:  D - down        P - in port-channel
        I - stand-alone s - suspended
        H - Hot-standby (LACP only)
        R - Layer3      S - Layer2
        U - in use      f - failed to allocate aggregator
        u - unsuitable for bundling
        w - waiting to be aggregated
        d - default port


Number of channel-groups in use: 1
Number of aggregators:           1

Group  Port-channel  Protocol    Ports
------+-------------+-----------+----------------------------------------------

1      Po1(RU)           -      Fa0/1(P) Fa0/2(P) Fa0/3(P) Fa0/4(P) 
Switch#show etherchannel ?
  load-balance  Load-balance/frame-distribution scheme among ports in
                port-channel
  port-channel  Port-channel information
  summary       One-line summary per channel-group
  
Switch#show etherchannel port-channel 
                Channel-group listing:
                ----------------------

Group: 1
----------
                Port-channels in the group:
                ---------------------------

Port-channel: Po1
------------

Age of the Port-channel   = 00d:00h:01m:14s
Logical slot/port   = 2/1       Number of ports = 4
GC                  = 0x00000000      HotStandBy port = null
Port state          = Port-channel 
Protocol            =   PAGP
Port Security       = Disabled

Ports in the Port-channel:

Index   Load   Port     EC state        No of bits
------+------+------+------------------+-----------
  0     00     Fa0/1    On                 0
  0     00     Fa0/2    On                 0
  0     00     Fa0/3    On                 0
  0     00     Fa0/4    On                 0
Time since last port bundled:    00d:00h:01m:14s    Fa0/4

The “show” commands should display enough information to troubleshoot the ether channel.

Note: on some switches the “no switchport” command is not available. I used a Layer 3 switch in Packet Tracer 7 to perform these labs. GNS3 does not support etherchannels.

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