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LAN trunk issue

weichenb2
Beginner
Beginner

            I have two 2950 LAN switches (dinosaurs) that am trying to connect via a trunk (Fa0/24 to Fa0/24). The configuration on both sides is as follows.

interface FastEthernet0/24

description Trunk to Madison-Ultra-2950-3, Fa0/24

switchport trunk allowed vlan 1,128,1002-1005

switchport mode trunk

&

interface FastEthernet0/24

description Trunk to Madison-Ultra-2950-4, Fa0/24

switchport trunk allowed vlan 1,128,1002-1005

switchport mode trunk

The interfaces on both sides come up/up but I never see the trunk come up and CDP info is nver share (even though configured globally and on interfaces). Also, I am unable to ping the GW (10.15.28.1) from switch 4. Finally, the interface Fa0/24 on switch 4 is taking excessive errors, even when I move the tunk to another port on switch 4 and replace cables. So, the errors cannot be attributed to the cable or the port. The errors seem to follow the link to the other switch.

6 Replies 6

mfurnival
Enthusiast
Enthusiast

Hi,

Can you post the config from both switches please?

What happens if you remove the trunking configuration from both ports - do they see each other via CDP and do the errors stop?

I hadn't thought about the cross-over cable. I will try one.

Madison-Ultra-2950-3#sh run int fa 0/24

Building configuration...

Current configuration : 160 bytes

!

interface FastEthernet0/24

description Trunk link to Madison-Ultra-2950-4, Fa0/24

switchport trunk allowed vlan 1,128,1002-1005

switchport mode trunk

-----

Madison-Ultra-2950-4#sh run int fa0/24

Building configuration...

Current configuration:

!

interface FastEthernet0/24

description Trunk to Madison-Ultra-2950-3, Gi0/2

switchport trunk allowed vlan 1,128,1002-1005

switchport mode trunk

======

Madison-Ultra-2950-3#sh int status | i 0/24

Fa0/24    Trunk link to Madi connected    trunk      a-full  a-100 10/100BaseTX

-----

Madison-Ultra-2950-4#sh int status | i 0/24

                                ^

% Invalid input detected at '^' marker.

==============

Madison-Ultra-2950-3#sh int fa 0/24

FastEthernet0/24 is up, line protocol is up (connected)

  Hardware is Fast Ethernet, address is 000f.2456.b6d8 (bia 000f.2456.b6d8)

  Description: Trunk link to Madison-Ultra-2950-4, Fa0/24

  MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,

     reliability 255/255, txload 1/255, rxload 1/255

  Encapsulation ARPA, loopback not set

  Keepalive set (10 sec)

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

  input flow-control is unsupported output flow-control is unsupported

  ARP type: ARPA, ARP Timeout 04:00:00

  Last input 00:53:42, output 00:00:00, output hang never

  Last clearing of "show interface" counters 00:04:41

  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 4000 bits/sec, 3 packets/sec

  5 minute output rate 0 bits/sec, 0 packets/sec

     800 packets input, 171540 bytes, 0 no buffer

     Received 800 broadcasts (0 multicast)

     0 runts, 0 giants, 0 throttles

     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored

     0 watchdog, 800 multicast, 0 pause input

     0 input packets with dribble condition detected

     517 packets output, 54306 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 PAUSE output

     0 output buffer failures, 0 output buffers swapped out

---------

Madison-Ultra-2950-4#sh int fa0/24

FastEthernet0/24 is up, line protocol is up

  Hardware is Fast Ethernet, address is 0005.325d.d158 (bia 0005.325d.d158)

  Description: Trunk to Madison-Ultra-2950-3, Gi0/2

  MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,

     reliability 143/255, txload 1/255, rxload 1/255

  Encapsulation ARPA, loopback not set

  Keepalive not set

  Auto-duplex (Full), Auto Speed (100), 100BaseTX/FX

  ARP type: ARPA, ARP Timeout 04:00:00

  Last input never, output 00:00:00, output hang never

  Last clearing of "show interface" counters 01:10:42

  Queueing strategy: fifo

  Output queue 0/40, 0 drops; input queue 0/75, 0 drops

  5 minute input rate 0 bits/sec, 0 packets/sec

  5 minute output rate 3000 bits/sec, 3 packets/sec

     0 packets input, 792923 bytes

     Received 0 broadcasts, 0 runts, 0 giants, 0 throttles

     7806 input errors, 7806 CRC, 0 frame, 0 overrun, 0 ignored

     0 watchdog, 0 multicast

     0 input packets with dribble condition detected

     13875 packets output, 1764946 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

======

Madison-Ultra-2950-3#sh int trunk

Port        Mode         Encapsulation  Status        Native vlan

Fa0/24      on           802.1q         trunking      1

Gi0/1       on           802.1q         trunking      1

Port      Vlans allowed on trunk

Fa0/24      1,128,1002-1005

Gi0/1       128

Port        Vlans allowed and active in management domain

Fa0/24      1,128

Gi0/1       128

Port        Vlans in spanning tree forwarding state and not pruned

Fa0/24      1,128

Gi0/1       128

--------

Madison-Ultra-2950-4#sh int trunk

                             ^

% Invalid input detected at '^' marker.

=====

Name : Fa0/24

Administrative Speed: auto

Administrative Duplex: auto

Administrative Auto-MDIX: N/A

Operational Speed: 100

Operational Duplex: full

Operational Auto-MDIX: N/A

------

=======

Madison-Ultra-2950-3#sh ip igmp snooping vlan 128

Global IGMP Snooping configuration:

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

IGMP snooping              : Enabled

IGMPv3 snooping (minimal)  : Enabled

Report suppression         : Enabled

TCN solicit query          : Disabled

TCN flood query count      : 2

Last member query interval : 1000

Vlan 128:

--------

IGMP snooping                       : Enabled

Immediate leave                     : Disabled

Multicast router learning mode      : pim-dvmrp

Source only learning age timer      : 10

Last member query interval          : 1000

CGMP interoperability mode          : IGMP_ONLY

upsilon22222
Beginner
Beginner

Since this is an older switch, have you verified that you are using a crossover cable and not a regular cable? I believe the older switches do not support the auto-sensing feature.

Otherwise, perhaps you could provide some output from the following commands:

sh run int fa 0/24 (on both switches)

sh int status | i 0/24

sh int fa 0/24 switchport (on both switches)

Madison-Ultra-2950-3#sh run int fa 0/24

Building configuration...

Current configuration : 160 bytes

!

interface FastEthernet0/24

description Trunk link to Madison-Ultra-2950-4, Fa0/24

switchport trunk allowed vlan 1,128,1002-1005

switchport mode trunk

-----

Madison-Ultra-2950-4#sh run int fa0/24

Building configuration...

Current configuration:

!

interface FastEthernet0/24

description Trunk to Madison-Ultra-2950-3, Gi0/2

switchport trunk allowed vlan 1,128,1002-1005

switchport mode trunk

======

Madison-Ultra-2950-3#sh int status | i 0/24

Fa0/24    Trunk link to Madi connected    trunk      a-full  a-100 10/100BaseTX

-----

Madison-Ultra-2950-4#sh int status | i 0/24

                                ^

% Invalid input detected at '^' marker.

==============

Madison-Ultra-2950-3#sh int fa 0/24

FastEthernet0/24 is up, line protocol is up (connected)

  Hardware is Fast Ethernet, address is 000f.2456.b6d8 (bia 000f.2456.b6d8)

  Description: Trunk link to Madison-Ultra-2950-4, Fa0/24

  MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,

     reliability 255/255, txload 1/255, rxload 1/255

  Encapsulation ARPA, loopback not set

  Keepalive set (10 sec)

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

  input flow-control is unsupported output flow-control is unsupported

  ARP type: ARPA, ARP Timeout 04:00:00

  Last input 00:53:42, output 00:00:00, output hang never

  Last clearing of "show interface" counters 00:04:41

  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 4000 bits/sec, 3 packets/sec

  5 minute output rate 0 bits/sec, 0 packets/sec

     800 packets input, 171540 bytes, 0 no buffer

     Received 800 broadcasts (0 multicast)

     0 runts, 0 giants, 0 throttles

     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored

     0 watchdog, 800 multicast, 0 pause input

     0 input packets with dribble condition detected

     517 packets output, 54306 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 PAUSE output

     0 output buffer failures, 0 output buffers swapped out

---------

Madison-Ultra-2950-4#sh int fa0/24

FastEthernet0/24 is up, line protocol is up

  Hardware is Fast Ethernet, address is 0005.325d.d158 (bia 0005.325d.d158)

  Description: Trunk to Madison-Ultra-2950-3, Gi0/2

  MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,

     reliability 143/255, txload 1/255, rxload 1/255

  Encapsulation ARPA, loopback not set

  Keepalive not set

  Auto-duplex (Full), Auto Speed (100), 100BaseTX/FX

  ARP type: ARPA, ARP Timeout 04:00:00

  Last input never, output 00:00:00, output hang never

  Last clearing of "show interface" counters 01:10:42

  Queueing strategy: fifo

  Output queue 0/40, 0 drops; input queue 0/75, 0 drops

  5 minute input rate 0 bits/sec, 0 packets/sec

  5 minute output rate 3000 bits/sec, 3 packets/sec

     0 packets input, 792923 bytes

     Received 0 broadcasts, 0 runts, 0 giants, 0 throttles

     7806 input errors, 7806 CRC, 0 frame, 0 overrun, 0 ignored

     0 watchdog, 0 multicast

     0 input packets with dribble condition detected

     13875 packets output, 1764946 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

======

Madison-Ultra-2950-3#sh int trunk

Port        Mode         Encapsulation  Status        Native vlan

Fa0/24      on           802.1q         trunking      1

Gi0/1       on           802.1q         trunking      1

Port      Vlans allowed on trunk

Fa0/24      1,128,1002-1005

Gi0/1       128

Port        Vlans allowed and active in management domain

Fa0/24      1,128

Gi0/1       128

Port        Vlans in spanning tree forwarding state and not pruned

Fa0/24      1,128

Gi0/1       128

--------

Madison-Ultra-2950-4#sh int trunk

                             ^

% Invalid input detected at '^' marker.

=====

Name : Fa0/24

Administrative Speed: auto

Administrative Duplex: auto

Administrative Auto-MDIX: N/A

Operational Speed: 100

Operational Duplex: full

Operational Auto-MDIX: N/A

------

=======

Madison-Ultra-2950-3#sh ip igmp snooping vlan 128

Global IGMP Snooping configuration:

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

IGMP snooping              : Enabled

IGMPv3 snooping (minimal)  : Enabled

Report suppression         : Enabled

TCN solicit query          : Disabled

TCN flood query count      : 2

Last member query interval : 1000

Vlan 128:

--------

IGMP snooping                       : Enabled

Immediate leave                     : Disabled

Multicast router learning mode      : pim-dvmrp

Source only learning age timer      : 10

Last member query interval          : 1000

CGMP interoperability mode          : IGMP_ONLY

Please post the commands:

sh int fa 0/24 switchport  (for both switches)

This command will show us the encapsulation and/or if there is a trunk negotiation occurring.

EDIT: Nevermind, I see you posted the trunk command alternative and I see you are using dot1q and the status is in "trunking mode".  Please let us know if your cable is correct.

  Are you sure you are connecting to the correct ports or are your descriptions just incorrect?  Switch 4 says it goes to G0/2  not 0/24 .   Also I don't understand why you can't do a show int trunk  or show interface status , are you sure they are both 2950's . Please post a show version from both switches.  Set both connecting ports to switchport mode access , this will make both an access port in vlan 1 and you should see cdp after this.  Once your ports are verified then you can put your trunk parameters back in and see what happens. Also make sure all your layer 2 vlans are created on both switches, verify with a show vlan .  I believe the gig ports on these is gig only so you cannot connect the gig ports to a fast ether port and have it work.

Madison-Ultra-2950-4#sh int fa0/24

FastEthernet0/24 is up, line protocol is up

  Hardware is Fast Ethernet, address is 0005.325d.d158 (bia 0005.325d.d158)

Description: Trunk to Madison-Ultra-2950-3, Gi0/2

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