All MIBs › CISCO-VTP-MIB › vtpMtuTooBig
vtpMtuTooBig
Module: CISCO-VTP-MIB
OID (symbolic): CISCO-VTP-MIB::vtpMtuTooBig
OID (numeric): 1.3.6.1.4.1.9.9.46.2.0.4
Node type: NOTIFICATION-TYPE
Description:
A VTP MTU tooBig notification is generated when a VLAN's MTU size is larger than can be supported either:
- by one or more of its trunk ports: the included vtpVlanState has the value 'mtuTooBigForTrunk' and the included vlanTrunkPortManagementDomain is for the first (or only) trunk port, or
- by the device itself: vtpVlanState has the value 'mtuTooBigForDevice' and any instance of vlanTrunkPortManagementDomain is included.
Devices which have no trunk ports do not send vtpMtuTooBig notifications.
Generation of this notification is suppressed if the vtpNotificationsEnabled has the value 'false'.
What is vtpMtuTooBig?
This notification is generated when a VLAN's maximum transmission unit (MTU) size exceeds what trunk ports or the device itself can support. The notification includes which trunk port has the limitation or whether the device as a whole is constrained, and helps network administrators identify configuration mismatches that could cause packet loss. Receiving this trap indicates that VLAN MTU settings need to be reduced or incompatible hardware needs to be upgraded.
Examples
Send this trap to an SNMP manager — replace <manager> with the IP or hostname of your monitoring server (SNMPv2c):
snmptrap -v2c -c public <manager> '' CISCO-VTP-MIB::vtpMtuTooBig snmptrap -v2c -c public <manager> '' 1.3.6.1.4.1.9.9.46.2.0.4
Listen for incoming traps on the manager host (-f keeps it in the foreground, -Lo prints to stdout — useful for testing):
snmptrapd -f -Lo -c /dev/null authCommunity log public
Example snmptrapd log entry:
zoo11-linux.zoo [UDP: [192.168.30.111]:50742->[192.168.30.10]:162]: DISMAN-EVENT-MIB::sysUpTimeInstance = Timeticks: (486759990) 56 days, 8:06:39.90 SNMPv2-MIB::snmpTrapOID.0 = OID: CISCO-VTP-MIB::vtpMtuTooBig
SNMPv3 example:
snmptrap -v3 -l authPriv -u snmpv3user -a SHA -A "AuthPass1" -x AES -X "PrivPass1" <manager> '' CISCO-VTP-MIB::vtpMtuTooBig
OID Breakdown
| Numeric OID | Name | Module |
|---|---|---|
| 1 | iso | LANART-AGENT |
| 1.3 | org | BIANCA-BRICK-PPP-MIB |
| 1.3.6 | dod | BIANCA-BRICK-PPP-MIB |
| 1.3.6.1 | internet | BIANCA-BRICK-PPP-MIB |
| 1.3.6.1.4 | private | BIANCA-BRICK-PPP-MIB |
| 1.3.6.1.4.1 | enterprises | ANIROOT-MIB |
| 1.3.6.1.4.1.9 | cisco | CISCO-SMI |
| 1.3.6.1.4.1.9.9 | ciscoMgmt | CISCO-SMI |
| 1.3.6.1.4.1.9.9.46 | ciscoVtpMIB | CISCO-VTP-MIB |
| 1.3.6.1.4.1.9.9.46.2 | vtpNotifications | CISCO-VTP-MIB |
| 1.3.6.1.4.1.9.9.46.2.0 | vtpNotificationsPrefix | CISCO-VTP-MIB |
| 1.3.6.1.4.1.9.9.46.2.0.4 | vtpMtuTooBig | CISCO-VTP-MIB |