07-01-2009 04:34 AM - edited 03-06-2019 06:32 AM
Hi Guys,
I have tried connecting 2 switch using a trunk port in able for VLAN to run on 2950 switch, 2950 and 2960G, but the problem is, it keeps going up and down when I check the logs. The client experienced intermittent network connection by this problem. What seems to be the problem here? I already replaced the cables.
Here is the config:
They are connected via cross-cable
2950:
Int f0/24 --> 100mbps port
switchport mode trunk
2960G:
Int G0/1 --> 1Gbps port
switchport mode trunk
*I believe they will auto negotiate their current speed and duplex.
Thanks in advance.
Cheers!
07-01-2009 04:41 AM
Do a "show ip int description" in each switch and verify both connected ports have the same speed and duplex settings.
07-01-2009 04:42 AM
Sorry.... do a "show interfaces status".
07-01-2009 04:56 AM
Yes, they have the same settings.
Here it is:
int g0/2
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 10/100/1000BaseTX
input flow-control is off, output flow-control is unsupported
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:23, output 00:00:00, output hang never
Last clearing of "show interface" counters 5d18h
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 21000 bits/sec, 21 packets/sec
5 minute output rate 495000 bits/sec, 180 packets/sec
5180581 packets input, 1243581478 bytes, 0 no buffer
Received 62493 broadcasts (0 multicast)
0 runts, 0 giants, 0 throttles
2 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog, 30119 multicast, 0 pause input
0 input packets with dribble condition detected
179416978 packets output, 2694243274 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
int f0/24
MTU 1500 bytes, BW 100000 Kbit, DLY 1000 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 00:00:00, output 00:00:00, output hang never
Last clearing of "show interface" counters 5d18h
Input queue: 2/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 504000 bits/sec, 180 packets/sec
5 minute output rate 22000 bits/sec, 22 packets/sec
179389710 packets input, 2690183405 bytes, 0 no buffer
Received 26481884 broadcasts (0 multicast)
0 runts, 0 giants, 0 throttles
4510 input errors, 3566 CRC, 243 frame, 0 overrun, 0 ignored
0 watchdog, 17984825 multicast, 0 pause input
0 input packets with dribble condition detected
5180070 packets output, 1243477217 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
07-01-2009 09:41 AM
Int f0/24 has a fair amount of errors on it seeing it was cleared only 5 days ago. This looks like it is the input side going into the f0/24 . This is usually a physical layer issue. Also try a different port , one at a time on each end. The 2950 only supports dot1q , not sure about the 2960 but that is a direct replacement for the 2950 model.
07-01-2009 04:50 AM
try to hard code your interface config to:
2950:
Int f0/24
speed 100
duplex full
2960G:
Int G0/1
speed 100
duplex full
kindly post the logs and config of each switch interface.
07-01-2009 05:04 AM
I have tried to hardcode the interfaces, but still it is going up and down.
Here is the logs, almost the same with 2950 up and down status:
%LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/2, changed state to up
%LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/2, changed state to down
%LINK-3-UPDOWN: Interface GigabitEthernet0/2, changed state to down
%LINK-3-UPDOWN: Interface GigabitEthernet0/2, changed state to up
%LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/2, changed state to up
%LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/2, changed state to down
%LINK-3-UPDOWN: Interface GigabitEthernet0/2, changed state to down
07-01-2009 05:25 AM
are both trunk set to same encapsulation? try using dot1q on both ends. make sure the gig port is set to 100 speed to adjust for the other fast e port. do a show run int x and post it here.
07-01-2009 05:49 AM
They are both set to trunk but I have'nt set any encapsulation? I'll try that tomorrow and let you know. Btw, is the 2950 and 2960G are compatible? Thanks.
07-01-2009 07:42 AM
My understanding was that the only trunk encapsulation type available on the 2950 and 2960 was dot1q.
What command would one use to enable isl or dot1q on a 2950 or 2960? It's not "switchport trunk encapsulation dot1q" like with other switches.
07-01-2009 03:02 PM
2950 & 2960 have only one trunk encapsulation and it's Dot1Q.
Have you tried changing the cables? Since the 2960 is MDI/MDIX enable (make sure it is), cross-over or straight through won't make a difference.
In the 2950, did you create the VLAN on the VLAN Database?
Try other switches, I'm suspecting the 2950 is faulty.
07-01-2009 07:21 PM
Hi,
please change to a straight cable and tells us whats the outcome. thanks
07-06-2009 06:57 PM
Hi Irvine,
2940/2950 only supports 802.1Q and since its only support 802.1Q its the default.
2960 supports ISL and 802.1Q and the default is ISL. Set the encapsulation to 802.1Q
Regards,
Dandy
07-06-2009 07:08 PM
Hi Dandy,
I'm using IOS 12.2(44)SE & 12.2(46)SE for my 2960 and I'm fairly certain this particular model will only support 802.1Q encapsulation.
Can you verify this? If you are able to get ISL, can you let me know how you've been able to achieve this? :)
Thanks.
07-07-2009 02:36 AM
Hi Leo,
You're right it doesn support ISL :)
I thought I was using ISL between my 2960 and 3750. Its 802.1Q
Regards,
Dandy
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