Catalyst 3750 Cross-Stack EtherChannels

PAgP cannot be enabled on cross-stack EtherChannels while LACP and manual mode (mode on) are supported on cross-stack EtherChannels.

C3750#sh switch
Switch/Stack Mac Address : 000f.2395.f500
                                           H/W   Current
Switch#  Role   Mac Address     Priority Version  State
----------------------------------------------------------
*1       Master 000f.2395.f500     15     0       Ready
 2       Member 0022.552d.f480     1      0       Ready



C3750#
C3750#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
C3750(config)#int range gi1/0/1, gi2/0/1
C3750(config-if-range)#switchport trunk encapsulation dot1q
C3750(config-if-range)#switchport mode trunk
C3750(config-if-range)#channel-group 1 mode desirable
Creating a port-channel interface Port-channel 1
%With PAgP enabled, all ports in the Channel should belong to the same switch
Command rejected (Port-channel1, Gi2/0/1): Invalid etherchnl mode

% Interface range command failed for GigabitEthernet2/0/1
C3750(config-if-range)#
C3750(config-if-range)#do sh etherchannel summary
Flags:  D - down        P - bundled 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

        M - not in use, minimum links not met
        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(SD)         PAgP      Gi1/0/1(D)

C3750(config-if-range)#
C3750(config-if-range)#channel-group 1 mode active
C3750(config-if-range)#do sh etherchannel summary
Flags:  D - down        P - bundled 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

        M - not in use, minimum links not met
        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(SD)         LACP      Gi1/0/1(D)  Gi2/0/1(D)

C3750(config-if-range)#
C3750(config-if-range)#no channel-group
C3750(config-if-range)#channel-group 1 mode on
C3750(config-if-range)#do sh etherchannel summary
Flags:  D - down        P - bundled 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

        M - not in use, minimum links not met
        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(SD)          -        Gi1/0/1(D)  Gi2/0/1(D)

C3750(config-if-range)#