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Author Topic: Slot Message size exceeded buffer maxMsgSize  (Read 958 times)

dobst

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Slot Message size exceeded buffer maxMsgSize
« on: July 12, 2016, 08:28:03 AM »
Hey everyone,

on on of our N9K-C9372PX-E I get the following error during discovery:

Code: [Select]
Modules      ------------------------------------------------------------------
SNMP:Connect 172.18.253.87 public v2 Tout:1s MaxMS:1472
ERR :Slot Message size exceeded buffer maxMsgSize

If I do this discovery with the Definiton Generator on OID 1.3.6.1.2.1.47.1.1.1.1.7 everything is fine:

Code: [Select]
172.18.253.87 public v2

 1.3.6.1.2.1.47.1.1.1.1.7


10: "Fabric Stack Root"
22: "N9K-C9372PX-E"
149: "N9K-C9372PX-E"
214: "LinecardSlot-1"
278: "PowerSupplyBay-1"
279: "PowerSupplyBay-2"
342: "FanBay-1"
343: "FanBay-2"
344: "FanBay-3"
345: "FanBay-4"
470: "PowerSupply-1"
471: "PowerSupply-2"
534: "Fan Module-1"
535: "Fan Module-2"
536: "Fan Module-3"
537: "Fan Module-4"
598: "module-1 processor-1"
5206: "Linecard-1 Port-1"
5207: "Linecard-1 Port-2"
5208: "Linecard-1 Port-3"
5209: "Linecard-1 Port-4"
5210: "Linecard-1 Port-5"
5211: "Linecard-1 Port-6"
5212: "Linecard-1 Port-7"
5213: "Linecard-1 Port-8"
5214: "Linecard-1 Port-9"
5215: "Linecard-1 Port-10"
5216: "Linecard-1 Port-11"
5217: "Linecard-1 Port-12"
5218: "Linecard-1 Port-13"
5219: "Linecard-1 Port-14"
5220: "Linecard-1 Port-15"
5221: "Linecard-1 Port-16"
5222: "Linecard-1 Port-17"
5223: "Linecard-1 Port-18"
5224: "Linecard-1 Port-19"
5225: "Linecard-1 Port-20"
5226: "Linecard-1 Port-21"
5227: "Linecard-1 Port-22"
5228: "Linecard-1 Port-23"
5229: "Linecard-1 Port-24"
5230: "Linecard-1 Port-25"
5231: "Linecard-1 Port-26"
5232: "Linecard-1 Port-27"
5233: "Linecard-1 Port-28"
5234: "Linecard-1 Port-29"
5235: "Linecard-1 Port-30"
5236: "Linecard-1 Port-31"
5237: "Linecard-1 Port-32"
5238: "Linecard-1 Port-33"
5239: "Linecard-1 Port-34"
5240: "Linecard-1 Port-35"
5241: "Linecard-1 Port-36"
5242: "Linecard-1 Port-37"
5243: "Linecard-1 Port-38"
5244: "Linecard-1 Port-39"
5245: "Linecard-1 Port-40"
5246: "Linecard-1 Port-41"
5247: "Linecard-1 Port-42"
5248: "Linecard-1 Port-43"
5249: "Linecard-1 Port-44"
5250: "Linecard-1 Port-45"
5251: "Linecard-1 Port-46"
5252: "Linecard-1 Port-47"
5253: "Linecard-1 Port-48"
5254: "Linecard-1 Port-49"
5255: "Linecard-1 Port-50"
5256: "Linecard-1 Port-51"
5257: "Linecard-1 Port-52"
5258: "Linecard-1 Port-53"
5259: "Linecard-1 Port-54"
38486: "module-1 FRONT"
38487: "module-1 BACK"
38488: "module-1 CPU"
38489: "module-1 TD2"
38490: "module-1 DONNER"
48854: "Transceiver(slot:1-port:1)"
48855: "Transceiver(slot:1-port:2)"
48856: "Transceiver(slot:1-port:3)"
48898: "Transceiver(slot:1-port:45)"
48899: "Transceiver(slot:1-port:46)"
48900: "Transceiver(slot:1-port:47)"
48901: "Transceiver(slot:1-port:48)"
300077443: "Ethernet1/45 Lane 1 Transceiver Voltage Sensor"
300077444: "Ethernet1/45 Lane 1 Transceiver Bias Current Sensor"
300077447: "Ethernet1/45 Lane 1 Transceiver Temperature Sensor"
300077453: "Ethernet1/45 Lane 1 Transceiver Receive Power Sensor"
300077454: "Ethernet1/45 Lane 1 Transceiver Transmit Power Sensor"
300079203: "Ethernet1/46 Lane 1 Transceiver Voltage Sensor"
300079204: "Ethernet1/46 Lane 1 Transceiver Bias Current Sensor"
300079207: "Ethernet1/46 Lane 1 Transceiver Temperature Sensor"
300079213: "Ethernet1/46 Lane 1 Transceiver Receive Power Sensor"
300079214: "Ethernet1/46 Lane 1 Transceiver Transmit Power Sensor"
300080963: "Ethernet1/47 Lane 1 Transceiver Voltage Sensor"
300080964: "Ethernet1/47 Lane 1 Transceiver Bias Current Sensor"
300080967: "Ethernet1/47 Lane 1 Transceiver Temperature Sensor"
300080973: "Ethernet1/47 Lane 1 Transceiver Receive Power Sensor"
300080974: "Ethernet1/47 Lane 1 Transceiver Transmit Power Sensor"
300082723: "Ethernet1/48 Lane 1 Transceiver Voltage Sensor"
300082724: "Ethernet1/48 Lane 1 Transceiver Bias Current Sensor"
300082727: "Ethernet1/48 Lane 1 Transceiver Temperature Sensor"
300082733: "Ethernet1/48 Lane 1 Transceiver Receive Power Sensor"
300082734: "Ethernet1/48 Lane 1 Transceiver Transmit Power Sensor"

What ist maxMsgSize and why is it exceeded?

rickli

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Re: Slot Message size exceeded buffer maxMsgSize
« Reply #1 on: July 21, 2016, 11:03:06 AM »
One of the major drawbacks of SNMP, you're supposed to know the size of the answer when sending the request :)

maxmesg is the size of the answer. If it exceeds MTU the packet is going to be fragmented. That's why I try to keep it below 1500 bytes and play with maxrepetitions (number of OIDs returned in bulk request).

This leads to such issues on bigger switches, but I'm trying to avoid them of course. Have a look at Modules() in libsnmp.pm. I have this in newer versions of NeDi:

   my @maxrep = (-maxrepetitions  => 12 );
Please consider Other-Invoices on your NeDi installation for an annual contribution, tx!
-Remo

dobst

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Re: Slot Message size exceeded buffer maxMsgSize
« Reply #2 on: February 16, 2017, 08:05:22 AM »
Hi Remo,

since I'm still running 1.0.9  :-[ I modified the following lines:

Code: [Select]
        my @maxrep = ();
        if($main::dev{$na}{rv} == 2){
                if($main::dev{$na}{os} eq "ESX"){                                                       # My ESXi works better this way, general problem?
                        @maxrep = (-maxrepetitions  => 3 );
                }else{
#                       @maxrep = (-maxrepetitions  => 25 );                                             # dobst 16.02.2017
                        @maxrep = (-maxrepetitions  => 5 );
                }
        }

Now modules are detected :-) Need to update to 1.5.0 :-) what is a bit difficult because I wrote an other GUI referring the old db scheme :-/