cancel
Showing results for 
Search instead for 
Did you mean: 
cancel
450
Views
20
Helpful
6
Replies

need help to troubleshoot with new switch config

djpk05
Level 1
Level 1

We recently replaced 3750 switch with 9300.  From the day one, I'm having an issue with various different things like https doesn't work to hosts that are connected to this switch.  I can't seem to ping anything bigger than data size of 1372.  The switch has a interface that terminated 1G p2p circuit to other location.  Location A has 9300 and Location B has 6509. 

A site interface ouput;

sw.erco#sho int g2/0/30
GigabitEthernet2/0/30 is up, line protocol is up (connected)
Hardware is Gigabit Ethernet, address is bcd2.951b.669e (bia bcd2.951b.669e)
Description: fiber - link to cco - fiberlight - 1Gbps
MTU 1500 bytes, BW 1000000 Kbit/sec, DLY 10 usec,
reliability 255/255, txload 10/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full-duplex, 1000Mb/s, media type is 10/100/1000BaseTX
input flow-control is on, output flow-control is unsupported
ARP type: ARPA, ARP Timeout 04:00:00
Last input never, output 00:00:00, output hang never
Last clearing of "show interface" counters 00:06:12
Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 1711000 bits/sec, 1215 packets/sec
5 minute output rate 41056000 bits/sec, 3719 packets/sec
459623 packets input, 80861440 bytes, 0 no buffer
Received 0 broadcasts (0 multicasts)
0 runts, 1156 giants, 0 throttles
1156 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog, 0 multicast, 0 pause input
0 input packets with dribble condition detected
1418214 packets output, 1959724015 bytes, 0 underruns
Output 0 broadcasts (0 multicasts)
0 output errors, 0 collisions, 0 interface resets
0 unknown protocol drops
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

Site B interface output:

sw-251-125#sho int g9/1
GigabitEthernet9/1 is up, line protocol is up (connected)
Hardware is C6k 1000Mb 802.3, address is 0017.5a0f.f554 (bia 0017.5a0f.f554)
Description: fiber - link to sw-md - fiberlight - 1Gbps
MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,
reliability 255/255, txload 1/255, rxload 10/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full-duplex, 1000Mb/s, media type is 1000BaseLH
input flow-control is off, output flow-control is off
Clock mode is auto
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:06, output 00:00:36, output hang never
Last clearing of "show interface" counters 1d17h
Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 40976000 bits/sec, 3720 packets/sec
5 minute output rate 1746000 bits/sec, 1244 packets/sec
455178497 packets input, 607545132282 bytes, 0 no buffer
Received 5199 broadcasts (4844 multicasts)
0 runts, 8 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog, 0 multicast, 0 pause input
0 input packets with dribble condition detected
158046269 packets output, 28269914802 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

As you can see, Site A interface is showing the errors.  No errors on Site B.  I'm wondering if this is what causing the issue we have.

0 runts, 1156 giants, 0 throttles
1156 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored

Never experienced the issue like this before... when we had the same setup with 3750, everything was fine.  With this 9300, we can ping but no https...  ospf doesn't form the "full" relationship with neighbor. 

Anyone has any suggestions?  Anything I should try?  Thanks.

6 Replies 6

many issue can cause that but let talk about p2p circuit via SP , are SP support more than 1372?

Thanks for your reply.  Nothing has changed on SP side, everything was fine with the old 3750 switches.  All the issues were started after we replaced with 9300.  I don't think the issue is with SP.  I just opened up a case with Cisco, also.  Hope they have some answer for this.  

but the MTU config is different between 3750 and 9300, 
can you confirm that you not adj the VLAN MTU in old 3750???

Hello,

what are the interfaces of which you show the output connected to ? Are these two switches directly connected, and if not, what is in between ? CRC errors usually mean some sort of (physical) problem with the cabling or interface. What if you use a different cable and/or interface on the Site A switch ?

djpk05
Level 1
Level 1

I was able to resolve the issue after spending hours of troubleshooting.   It turned out the issue was with MTU settings.  I had to issue "system mtu 9198" on the new switch.  I looked at the old switch and it was running system wide mtu 9198.  Once I change the setting, all the weird issues were gone instantly like OSPF not forming, can't ping anything above 1400, etc.  One line of command... that did it.  Thanks for your help.

As I get from first time 
I am so glad your issue solve 
good job and good luck 

Review Cisco Networking products for a $25 gift card