Forum Discussion

Aspirant

Oct 26, 2016

M4100 managed switches in series - dropping connection briefly

Hi all, Firstly, I'm totally new to this forum and have searched for my issue without success.. so apologies if this has been discussed before. The problem... I have an issue with a user usi...

Solutions

Troubleshooting

nhickey

Aspirant

Nov 03, 2016

Hi John / Erik,

Thanks for your replys.. they are much appreciated, and also excuse the delay getting back to you!

I have checked the port statistics as suggested. There are four ports in use, but they are all showing '0' for total transmit errors and total transmit packets discarded. When I try to ping the switch IP I get periodic breaks, so I figured that the uplink port (port 12 fibre port) would show an error, but it did not. Here is the statistics from the port, the stats were cleared in the last hour and a half, but the user has complained of drop out in that time period.. can you guys can see something I'm missing?:

Interface	0/12
MST ID	CST
ifIndex	12
Port Type	Normal
Port Channel ID	Disable
Port Role	Designated
STP Mode	Enable
STP State	Forwarding
Admin Mode	Enable
Flow Control Mode	Disable
LACP Mode	Enable
Physical Mode	Auto
Physical Status	1000 Mbps
Link Status	Link Up
Link Trap	Enable
Packets RX and TX 64 Octets	78023
Packets RX and TX 65-127 Octets	114250
Packets RX and TX 128-255 Octets	38808
Packets RX and TX 256-511 Octets	27107
Packets RX and TX 512-1023 Octets	9823
Packets RX and TX 1024-1518 Octets	56225
Packets RX and TX 1519-2047 Octets	0
Packets RX and TX 2048-4095 Octets	0
Packets RX and TX 4096-9216 Octets	0
Octets Received	106342746
Packets Received 64 Octets	65226
Packets Received 65-127 Octets	65099
Packets Received 128-255 Octets	34937
Packets Received 256-511 Octets	22983
Packets Received 512-1023 Octets	7947
Packets Received 1024-1518 Octets	51359
Packets Received > 1518 Octets	9
Total Packets Received Without Errors	230492
Unicast Packets Received	82407
Multicast Packets Received	56898
Broadcast Packets Received	91187
Receive Packets Discarded	0
Total Packets Received with MAC Errors	14255
Jabbers Received	0
Fragments Received	200
Undersize Received	0
Alignment Errors	0
Rx FCS Errors	14055
Overruns	0
Total Received Packets Not Forwarded	9
802.3x Pause Frames Received	0
Unacceptable Frame Type	0
Total Packets Transmitted (Octets)	15104341
Packets Transmitted 64 Octets	12797
Packets Transmitted 65-127 Octets	49151
Packets Transmitted 128-255 Octets	3871
Packets Transmitted 256-511 Octets	4124
Packets Transmitted 512-1023 Octets	1876
Packets Transmitted 1024-1518 Octets	4866
Packets Transmitted > 1518 Octets	0
Maximum Frame Size	1518
Total Packets Transmitted Successfully	76685
Unicast Packets Transmitted	66702
Multicast Packets Transmitted	6101
Broadcast Packets Transmitted	3882
Transmit Packets Discarded	0
Total Transmit Errors	0
Total Transmit Packets Discarded	0
Single Collision Frames	0
Multiple Collision Frames	0
Excessive Collision Frames	0
STP BPDUs Received	0
STP BPDUs Transmitted	0
RSTP BPDUs Received	6
RSTP BPDUs Transmitted	2738
MSTP BPDUs Received	0
MSTP BPDUs Transmitted	0
802.3x Pause Frames Transmitted	0
GVRP PDUs Received	0
GVRP PDUs Transmitted	0
GVRP Failed Registrations	0
GMRP PDUs Received	0
GMRP PDUs Transmitted	0
GMRP Failed Registrations	0
EAPOL Frames Received	0
EAPOL Frames Transmitted	0
Time Since Counters Last Cleared	0 day 1 hr 31 min 47 sec

Thanks So so much,

Neil

Retired_Member

Nov 04, 2016

Hi nhickey,

Thanks for your updating immediately.

I found that there is some 'Rx FCS Errors' in the port statistics. Which type fiber module you are using? Could you change another pair of fiber module and try again?

Thanks,

Eric
NETGEAR Employee

nhickey
Aspirant
Nov 04, 2016
Hi Eric,

The SFP mudule we are using is a Netgear one.. here's a link:

https://www.netgear.com/business/products/switches/modules-accessories/agm732f.aspx?cid=wmt_netgear_organic

Could there be a fault in the cable?? The trouble is, the cable connecting the two switches is under ground!

We have no spare SFP modules, and would need to get new ones. Would you recommend we do that?

Thanks,

Neil
- nhickey
  Aspirant
  Nov 04, 2016
  Hi guys,
  
  I have another possible theory.. could heat be a factor? I'll try to describe..
  
  We have a (approx) 250 meter fibre connection between the server room and the first M4100 D12 switch. This switch is situated in a 'pavilion' type building beside some tennis courts. It's in a communications cabinet mounted onto the wall, but there is no cooling in this cabinet. The issue seems to have appeard as we have been coming into our summer (we're in Zimbabwe by the way!). Temperature wise, we were up to 41C the other day or 105 F!). The user seems to think it's getting worse too, which would go with the heat theory.
  
  It's just after midday here, so I took a walk to check the units visually. I took out the SFP module going to the second D12 and found it to be very, very hot!. I'm starting to think that the heat could be the problem.. and that we may be reaching the temperature limit of these modules!
  
  What do you reckon? am I clutching at straws, so to speak!
  
  Thanks,
  
  Neil
  - Retired_Member
    Nov 07, 2016
    Hi nhickey,
    
    I'm afraid it may cause switch some abnormal behavior when the environment temperature is too high. But we still cannot make sure. It's will be better that switch working on air condition environment.
    
    Below is the 'Site requirements for switch location' for Netgear Switch. Although the DUT working condition is in the range of desired, but the high temperature cause SFP module too hot, and it may cause some abnormal.
    
    Thanks,
    
    EricZ
    NETGEAR Employee