PAgP port in stand-alone mode

simionov.adrian · ‎03-24-2013

Devices are 3750-24TS Switches, software version is 12.2(55)SE6.

I need some more advices about how to troubleshoot this issue, I have a pair of ports which are not bundling, no matter what. Is the same behavior with LACP or PAgP. In this outputs I have only the PAgP case.

Output is similar to:

Group Port-channel Protocol Ports

------+-------------+-----------+-----------------------------------------------

12 Po12(SD) PAgP Fa1/0/23(I) Fa1/0/24(I)

Configuration on ports is simple:

SW1:

interface FastEthernet1/0/24

switchport trunk encapsulation dot1q

switchport mode trunk

channel-group 12 mode desirable

end

interface FastEthernet1/0/23

switchport trunk encapsulation dot1q

switchport mode trunk

channel-group 12 mode desirable

end

SW2:

interface FastEthernet1/0/23

switchport trunk encapsulation dot1q

switchport mode trunk

channel-group 12 mode desirable

end

interface FastEthernet1/0/24

switchport trunk encapsulation dot1q

switchport mode trunk

channel-group 12 mode desirable

end

Cables are connected:

SW1#sh cdp neighbors | i SW2

SW2 Fas 1/0/24 168 S I WS-C3750- Fas 1/0/24

SW2 Fas 1/0/23 167 S I WS-C3750- Fas 1/0/23

SW1#

SW2#sh cdp neighbors | i SW1

SW1 Fas 1/0/24 131 S I WS-C3750- Fas 1/0/24

SW1 Fas 1/0/23 131 S I WS-C3750- Fas 1/0/23

SW2#

IOS is stating that port negociation is working ok.

SW1#sh int fa 1/0/23 | i media

Full-duplex, 100Mb/s, media type is 10/100BaseTX

SW1#sh int fa 1/0/24 | i media

Full-duplex, 100Mb/s, media type is 10/100BaseTX

SW1#

SW2#sh int fa1/0/23 | i media

Full-duplex, 100Mb/s, media type is 10/100BaseTX

SW2#sh int fa1/0/24 | i media

Full-duplex, 100Mb/s, media type is 10/100BaseTX

SW2#

Some troubleshooting steps:

I rebooted the switches and changed the cables.

I made advanced diagnostics for hardware faults of the devices, diag passed.

I noticed that on SW 2 there are no received counters, but I did not make a sniff yet to know if are not sent, or not understood by the other side.

SW1#sh pagp counter

Information Flush PAgP

Port Sent Recv Sent Recv Err Pkts

---------------------------------------------------

Channel group: 12

Fa1/0/23 2162 158 0 0 0

Fa1/0/24 2163 159 0 0 0

SW2#sh pagp counters

Information Flush PAgP

Port Sent Recv Sent Recv Err Pkts

---------------------------------------------------

Channel group: 12

Fa1/0/23 167 0 0 0 0

Fa1/0/24 169 0 0 0 0

I made debug and I get the following log. Last 4 logs will repeat forever.

*Mar 1 11:31:01.985: FEC: pagp_switch_stay_shutdown: port Fa1/0/23 agport Po12

*Mar 1 11:31:01.985: FEC: pagp_switch_stay_shutdown: port Fa1/0/24 agport Po12

*Mar 1 11:31:01.994: FEC: pagp_switch_hwif_comingup: port Po12

*Mar 1 11:31:01.994: FEC: pagp_switch_reset_cannot_bundle_ports: group 12

*Mar 1 11:31:03.990: %LINK-3-UPDOWN: Interface FastEthernet1/0/23, changed state to up

*Mar 1 11:31:03.990: %LINK-3-UPDOWN: Interface FastEthernet1/0/24, changed state to up

*Mar 1 11:31:06.523: FEC: pagp_switch_port_up: Fa1/0/23

*Mar 1 11:31:06.523: FEC: pagp_switch_invoke_port_up: Fa1/0/23

*Mar 1 11:31:06.523: FEC: pagp_switch_agc_compatable: comparing GC values of Fa1/0/23 Po12 flag = 1 1

*Mar 1 11:31:06.523: FEC: pagp_switch_port_attrib_diff: Fa1/0/23 Po12 same

*Mar 1 11:31:06.523: FEC: pagp_switch_agc_compatable: GC values are compatable

*Mar 1 11:31:06.523: FEC: pagp_switch_find_master: group 12

*Mar 1 11:31:06.523: FEC: pagp_switch_calculate_vgc: gc for port Fa1/0/23 is C0001

*Mar 1 11:31:06.523: FEC: pagp_switch_port_up: Fa1/0/24

*Mar 1 11:31:06.523: FEC: pagp_switch_invoke_port_up: Fa1/0/24

*Mar 1 11:31:06.523: FEC: pagp_switch_agc_compatable: comparing GC values of Fa1/0/24 Po12 flag = 1 1

*Mar 1 11:31:06.523: FEC: pagp_switch_port_attrib_diff: Fa1/0/24 Po12 same

*Mar 1 11:31:06.523: FEC: pagp_switch_agc_compatable: GC values are compatable

*Mar 1 11:31:06.523: FEC: pagp_switch_find_master: group 12

*Mar 1 11:31:06.523: FEC: pagp_switch_agc_compatable: comparing GC values of Fa1/0/24 Fa1/0/23 flag = 1 1

*Mar 1 11:31:06.523: FEC: pagp_switch_port_attrib_diff: compare PAgP modes for Fa1/0/24

*Mar 1 11:31:06.523: FEC: pagp_switch_port_attrib_diff: Fa1/0/24 Fa1/0/23 same

*Mar 1 11:31:06.523: FEC: pagp_switch_agc_compatable: GC values are compatable

*Mar 1 11:31:06.532: FEC: pagp_switch_agc_compatable: comparing GC values of Fa1/0/24 Fa1/0/23 flag = 1 1

*Mar 1 11:31:06.532: FEC: pagp_switch_port_attrib_diff: compare PAgP modes for Fa1/0/24

*Mar 1 11:31:06.532: FEC: pagp_switch_port_attrib_diff: Fa1/0/24 Fa1/0/23 same

*Mar 1 11:31:06.532: FEC: pagp_switch_agc_compatable: GC values are compatable

*Mar 1 11:31:06.532: FEC: pagp_switch_calculate_vgc: gc for port Fa1/0/24 is C0001

*Mar 1 11:31:31.765: FEC: fec_dontbundle: Fa1/0/23

*Mar 1 11:31:31.765: FEC: pagp_switch_independent_port: Fa1/0/23

*Mar 1 11:31:31.798: FEC: pagp_switch_reset_load_index: reading load-index for port Fa1/0/23

*Mar 1 11:31:31.933: FEC: fec_dontbundle: Fa1/0/24

*Mar 1 11:31:31.933: FEC: pagp_switch_independent_port: Fa1/0/24

*Mar 1 11:31:31.966: FEC: pagp_switch_reset_load_index: reading load-index for port Fa1/0/24

*Mar 1 11:31:32.889: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet1/0/23, changed state to up

*Mar 1 11:31:33.099: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet1/0/24, changed state to up

*Mar 1 11:31:40.086: FEC: fec_unbundle: Fa1/0/23

*Mar 1 11:31:40.086: FEC: pagp_switch_change_vgc: gcchngreq == 0 for Fa1/0/23

*Mar 1 11:31:40.086: FEC: pagp_switch_change_vgc: Fa1/0/23 gcchngreq = 0 gc = C0001

*Mar 1 11:31:40.086: FEC: pagp_switch_unindependent_port: Fa1/0/23

*Mar 1 11:31:42.267: FEC: fec_unbundle: Fa1/0/24

*Mar 1 11:31:42.267: FEC: pagp_switch_change_vgc: gcchngreq == 0 for Fa1/0/24

*Mar 1 11:31:42.267: FEC: pagp_switch_change_vgc: Fa1/0/24 gcchngreq = 0 gc = C0001

*Mar 1 11:31:42.267: FEC: pagp_switch_unindependent_port: Fa1/0/24

*Mar 1 11:31:57.132: FEC: fec_dontbundle: Fa1/0/23

*Mar 1 11:31:57.132: FEC: pagp_switch_independent_port: Fa1/0/23

*Mar 1 11:31:57.132: FEC: pagp_switch_reset_load_index: reading load-index for port Fa1/0/23

*Mar 1 11:31:59.237: FEC: fec_dontbundle: Fa1/0/24

*Mar 1 11:31:59.237: FEC: pagp_switch_independent_port: Fa1/0/24

*Mar 1 11:31:59.237: FEC: pagp_switch_reset_load_index: reading load-index for port Fa1/0/24

*Mar 1 11:32:06.401: FEC: fec_unbundle: Fa1/0/23

*Mar 1 11:32:06.401: FEC: pagp_switch_change_vgc: gcchngreq == 0 for Fa1/0/23

*Mar 1 11:32:06.401: FEC: pagp_switch_change_vgc: Fa1/0/23 gcchngreq = 0 gc = C0001

*Mar 1 11:32:06.401: FEC: pagp_switch_unindependent_port: Fa1/0/23

*Mar 1 11:32:11.980: FEC: fec_unbundle: Fa1/0/24

*Mar 1 11:32:11.980: FEC: pagp_switch_change_vgc: gcchngreq == 0 for Fa1/0/24

*Mar 1 11:32:11.980: FEC: pagp_switch_change_vgc: Fa1/0/24 gcchngreq = 0 gc = C0001

*Mar 1 11:32:11.980: FEC: pagp_switch_unindependent_port: Fa1/0/24

*Mar 1 11:32:23.749: FEC: fec_dontbundle: Fa1/0/23

*Mar 1 11:32:23.749: FEC: pagp_switch_independent_port: Fa1/0/23

*Mar 1 11:32:23.749: FEC: pagp_switch_reset_load_index: reading load-index for port Fa1/0/23

*Mar 1 11:32:29.193: FEC: fec_dontbundle: Fa1/0/24

*Mar 1 11:32:29.193: FEC: pagp_switch_independent_port: Fa1/0/24

*Mar 1 11:32:29.193: FEC: pagp_switch_reset_load_index: reading load-index for port Fa1/0/24

*Mar 1 11:32:33.337: FEC: fec_unbundle: Fa1/0/23

*Mar 1 11:32:33.337: FEC: pagp_switch_change_vgc: gcchngreq == 0 for Fa1/0/23

*Mar 1 11:32:33.337: FEC: pagp_switch_change_vgc: Fa1/0/23 gcchngreq = 0 gc = C0001

*Mar 1 11:32:33.337: FEC: pagp_switch_unindependent_port: Fa1/0/23

*Mar 1 11:32:40.837: FEC: fec_unbundle: Fa1/0/24

*Mar 1 11:32:40.837: FEC: pagp_switch_change_vgc: gcchngreq == 0 for Fa1/0/24

*Mar 1 11:32:40.837: FEC: pagp_switch_change_vgc: Fa1/0/24 gcchngreq = 0 gc = C0001

*Mar 1 11:32:40.837: FEC: pagp_switch_unindependent_port: Fa1/0/24

paul driver · ‎03-24-2013

Hello
wondering as these are 3750s are the ports you are trying to connect just are the provisioned ports and not actually the correct physical ports

without ehterchannel can you trunk between the two swiches? - if so
for pagp try port-channel mode non silent

res
Paul

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Paul

InayathUlla Sharieff · ‎03-24-2013

Hi,

If I was you I could have tried the following thing:

Step 1 : Default the configuration on both the interface.

Step 2 : Re-configure the interface

Ex:

interface FastEthernet1/0/23 & interface FastEthernet1/0/24

no shut

switchport

switchport trunk encapsulation dot1q

switchport mode trunk

no ip address

channel-group 12 mode desirable -- If this doesnt work try with mode "on"

Step 3 : Under the port channel add the configuration for trunk.

ex:

int port-channel 12

no shut

switchport trunk encapsulation dot1q

switchport mode trunk

no ip address.

Kindly do the same and provide us the result.

Outputs required for troubleshooting:

show etherchannel summary

show int trunk

show spanning-tree interface port-channel 12

show spanning-tree interface FastEthernet1/0/23 & 24

show log

HTH

Regards

Inayath

*Plz rate the usefull posts.

simionov.adrian · ‎03-25-2013

I finally solved this issue.

The problem was with a vlan filtering access list which was matching all mac addresses and was applied to all vlans.

After modifying the access-list to permit this new mac addresses everything was ok.