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I hope can someone help me with my problem on my Cisco 2960 switch.

My question is this: when I configure the Gig0/1 port on my client 2960 switch as trunk, and connect it to my server 3560 switch on port Gig0/24 with switchport trunk encapsulation dot1q and switchport mode trunk, there is no connection running on either port, and when I check the status of the of my 2960 port, this is what I get:

GigabitEthernet0/1 is down, line protocol is down (notconnect)
Hardware is Gigabit Ethernet, address is 0018.18da.8b81 (bia 0018.18da.8b81)
MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,
 reliability 255/255, txload 1/255## Heading ##, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Auto-duplex, Auto-speed, media type is 10/100/1000BaseTX
input flow-control is off, output flow-control is unsupported
ARP type: ARPA, ARP Timeout 04:00:00
Last input never, output never, output hang never
Last clearing of "show interface" counters never
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 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
 0 packets input, 0 bytes, 0 no buffer
 Received 0 broadcasts (0 multicast)
 0 runts, 0 giants, 0 throttles

When I connect Gig0/24 to another port on my 2960, for example port gig0/2, and configure it as trunk, it status connected, and there is a connection.

Is this a bad port?

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7
  • 3
    Double check the connection, do you have lights? Bad cable? I would say it is a "Layer 1" problem.
    – mrlayance
    Jun 11, 2015 at 16:24
  • 7
    Please attach the port configuration for both gig0/1 and gig0/2. Double check wiring, patch panel connections, etc.
    – HAL
    Jun 11, 2015 at 16:27
  • in a default, powering the cisco 2960 the LED light on port gig0/1, but after that when i connect cable it doesnt light. no matter what i do on configuring the port still no connection. i also clean the port, maybe some dust but stil no work. all the port on 3560 and 2960 are all running except to that port gig0/1 on 2960. theres no error. i use a new cable but doesnt work also. i suspek a terminal lost connection to that port. hardware.
    – Unchanging_Heart
    Jun 12, 2015 at 3:48
  • 2
    Had you check the cable before??. Try to change the MDI-X configuration on the ports.
    – Orlando Gaetano
    May 2, 2016 at 19:27
  • 1
    I agree, it is likely a layer 1 issue. You can verify if it is a bad port by configuring it as an access port and testing.
    – AJ.
    Nov 29, 2016 at 5:30

3 Answers 3

Reset to default
0

just a couple of extra thoughts i think may help.

-check for port-security issues

-if it is indeed a faulty port, you could try guiding the cable in an upwards direction (helped me on more than 1 occasion)reference picture cabling

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0

Cisco switch catalyst 2960 is layer2 switch . The command you used is not compatible with layer2 switch for Configuring trunk port .

Gig0/24 with switchport trunk encapsulation dot1q and switchport mode trunk

Instead of above command , use below command

Switch(config)#int Gig0/24

Switch(config)#switchport mode trunk

Switch(config)#switchport trunk allowed vlan all

Switch(config)#no shutdown

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-1

Sound's like a layer 1 problem as pointed out by mrlayance.

Taking into consideration one of the switchports isn't faulty, try a Cat5E or Cat6 cross-over cable between the two switches. Then try these commands on the trunk interfaces:

conf t
int gi0/x
shut
no mdix auto
speed 1000
duplex full
switchport nonegotiate
no shut

These links should assist you further:

https://learningnetwork.cisco.com/thread/21541

https://cciepursuit.wordpress.com/2007/07/08/switch-cabling-and-auto-mdix/

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2
  • 2
    Deactivating auto negotiation potentially leads to a duplex mismatch (which is very ugly) and (as per standard) disables gigabit and faster rates.
    – Zac67 ♦
    Jun 27, 2017 at 9:59
  • Agreed. Never disable auto negotiation and/or auto speed and duplex on modern network equipment unless you have absolutely no other choice and then only temporarily while you figure out the real cause of the problem.
    – FrameHowitzer
    Nov 16, 2022 at 15:27

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