CISCOSB-UDLD-MIB

All MIBs › CISCOSB-UDLD-MIB

Organization: CISCOSB Computer Communications Ltd.

Last Updated: 2012-08-01

Category: Network Interfaces, Vendor: RADLAN/Cisco SB

Description: Manages Unidirectional Link Detection (UDLD) configuration and port state on Cisco Small Business switches.

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What Is CISCOSB-UDLD-MIB?

CISCOSB-UDLD-MIB is a Cisco Small Business private MIB implementing Unidirectional Link Detection (UDLD), a Layer-2 protocol that detects one-way (unidirectional) fiber or copper links that standard link-state detection can miss. It exposes per-port administrative and operational UDLD mode, bidirectional state, detected-neighbor counts, and a neighbor table with device IDs. This is a hardware/link-health MIB: it is used to catch failing transceivers or miswired fiber pairs that would otherwise cause a spanning-tree loop or silent traffic black-hole, by confirming a link is truly bidirectional rather than just showing carrier. It works alongside standard link-layer/interface MIBs (IF-MIB ifIndex) since UDLD is applied per physical port. It is deployed on Cisco Small Business switches wherever fiber uplinks or trunk connections need protection against unidirectional-link failures. Engineers can download the CISCOSB-UDLD-MIB file directly to load it into their MIB browser.

IPNetwork Monitor allows you to monitor SNMP objects defined in CISCOSB-UDLD-MIB. Use the built-in SNMP Monitoring Browser to explore available variables, view their current values and descriptions, and select the objects you want to monitor. You can then create SNMP monitors, configure thresholds, and receive alerts when monitored values change.

Supported Devices

Cisco Small Business switches

Monitoring Examples

An administrator would poll rlUdldPortTable/rlUdldPortEntry to compare rlUdldPortAdminMode against rlUdldPortOperMode per rlUdldPortIfIndex, confirming UDLD is both configured and actually running on a critical fiber uplink. The rlUdldBidirectionalState reveals whether the link is confirmed bidirectional, while rlUdldNumberOfDetectedNeighbors and rlUdldNeighborTable's rlUdldNeighborDeviceID identify the connected peer switch. A port reporting rlUdldBidirectionalState as not-bidirectional despite an up link-state is the classic sign of a unidirectional fiber fault UDLD is designed to catch before it causes a loop.

What Can Be Monitored

UDLD admin vs. operational mode per port
bidirectional link state
number of detected neighbors
neighbor device ID

Imported Objects

From CISCOSB-MIB

rndNotifications	OBJECT-IDENTITY
switch001	MODULE-IDENTITY

From IF-MIB

InterfaceIndex

From SNMP-FRAMEWORK-MIB

SnmpAdminString

From SNMPv2-CONF

MODULE-COMPLIANCE
NOTIFICATION-GROUP
OBJECT-GROUP

From SNMPv2-SMI

Gauge32
Integer32
MODULE-IDENTITY
NOTIFICATION-TYPE
OBJECT-TYPE
Unsigned32

From SNMPv2-TC

MacAddress
RowStatus
TEXTUAL-CONVENTION
TruthValue

How to Use in IPNetwork Monitor

Example using rlUdldNumberOfDetectedNeighbors OID:

Select a Cisco Small Business switch as the target host to create a monitor — the SNMP service should be up and running on it. Click New Monitor, then check SNMP Custom on the Favorites tab, click Next, and confirm the host. On the next page, click Select... to open the built-in SNMP MIB Browser and type rlUdldNumberOfDetectedNeighbors into the Find box to locate it in the OID tree, selecting the specific row/instance you want to monitor since this is a table column, then select it and click OK. It reports the number Of Detected Neighbors for this port. On the monitor's Main parameters page you can set the target's SNMP port (default 161), credentials, polling interval, and other settings — see the SNMP Monitor help for details. On the State conditions and Alerting tabs, configure when the monitor should change state and trigger an alert; since this is an INTEGER-type OID, Value bounds is the most useful condition here — trigger an alert if the count changes from its expected baseline, since that would indicate the underlying set of items changed unexpectedly. Click Finish to create the monitor; you can adjust any parameter later.

OIDs

OID symbolic	OID numeric	Type	Access	Description
rlUdld	1.3.6.1.4.1.9.6.1.101.218			This private MIB module for UDLD (Cisco Systems UniDirectional Link Detection Protocol).
rlUdldPortTable	1.3.6.1.4.1.9.6.1.101.218.1		not-accessible	The table holds information for Udld Ethernet ports.
rlUdldPortEntry	1.3.6.1.4.1.9.6.1.101.218.1.1		not-accessible	Entry in the rlUdldPortTable.
NUM rlUdldPortIfIndex	1.3.6.1.4.1.9.6.1.101.218.1.1.1	InterfaceIndex	not-accessible	Interface Index. This variable is the key for udld port table. uniquely identifies the udld port information.
UDL rlUdldPortAdminMode	1.3.6.1.4.1.9.6.1.101.218.1.1.2	UdldPortMode	read-write	This variable identifies port UDLD admin configured mode (normal, aggressive, disable).
UDL rlUdldPortOperMode	1.3.6.1.4.1.9.6.1.101.218.1.1.3	UdldPortMode	read-only	This variable identifies port UDLD operational mode (normal, aggressive, disable). for fiber ports it is combination of global mode and port mode
T/F rlUdldPortDefaultConfiguration	1.3.6.1.4.1.9.6.1.101.218.1.1.4	TruthValue	read-only	This variable indicates whether tne user configure the udld port. to present (default) or not in port configuration.
UDL rlUdldBidirectionalState	1.3.6.1.4.1.9.6.1.101.218.1.1.5	UdldPortBidirectionalState	read-only	This variable identifies the port UDLD status (shutdown, idle, detection, undetermined, bidirectional).
INT rlUdldNumberOfDetectedNeighborsEx	1.3.6.1.4.1.9.6.1.101.218.1.1.6	INTEGER	read-only	Number Of Detected Neighbors for this port.
rlUdldNeighborTable	1.3.6.1.4.1.9.6.1.101.218.2		not-accessible	The table holds information for Udld Neighbor of ethernet ports.
rlUdldNeighborEntry	1.3.6.1.4.1.9.6.1.101.218.2.1		not-accessible	Entry in the rlUdldNeighborTable.
NUM rlUdldNeighborPortIfIndex	1.3.6.1.4.1.9.6.1.101.218.2.1.1	InterfaceIndex	not-accessible	Interface Index. This variable is the key for udld port Neighbor table. uniquely identifies the udld port index.
STR rlUdldNeighborDeviceID	1.3.6.1.4.1.9.6.1.101.218.2.1.2	UdldString	not-accessible	The Neighbor Device-ID TLV should contain the switch base MAC address in ACSII format.
STR rlUdldNeighborPortID	1.3.6.1.4.1.9.6.1.101.218.2.1.3	UdldString	not-accessible	The Port-ID TLV should contain the port ACSII name as it is printed in show CLI commands.
MAC rlUdldNeighborDeviceMACAddress	1.3.6.1.4.1.9.6.1.101.218.2.1.4	MacAddress	not-accessible	The Neighbor mac address
STR rlUdldNeighborDeviceName	1.3.6.1.4.1.9.6.1.101.218.2.1.5	UdldString	read-only	The Neighbor NeighborDevice Name TLV should contain sysName in ACSII.
INT rlUdldNeighborMessageTime	1.3.6.1.4.1.9.6.1.101.218.2.1.6	INTEGER	read-only	The Neighbor Message Time is from Message Interval TLV. This time interval value used by a neighbor to send UDLD probes after the linkup or detection phases. Its time unit is 1 second.
INT rlUdldNeighborLeftLifeTime	1.3.6.1.4.1.9.6.1.101.218.2.1.7	INTEGER	read-only	The remaining holdtime for Neighbor entry in cache in seconds.
UDL rlUdldNeighborCurrentState	1.3.6.1.4.1.9.6.1.101.218.2.1.8	UdldNeighborCurrentState	read-only	This variable identifies the Neighbor port UDLD current status (Disabled, Enabled, Undefined, Bidirectional).
UDL rlUdldGlobalUDLDMode	1.3.6.1.4.1.9.6.1.101.218.3	UdldGlobalMode	read-write	Define Global UDLD Mode (normal, aggressive, disable)
INT rlUdldGlobalMessageTime	1.3.6.1.4.1.9.6.1.101.218.4	INTEGER	read-write	Define global value of the interval between two sent probe messages, use the udld message time command in Global Configuration mode.

RFC description

Cisco Systems UniDirectional Link Detection (UDLD) protocol management for fiber port monitoring.

Start monitoring Cisco Small Business switches with a free 30-day trial of IPNetwork Monitor. Import MIBs, browse SNMP OIDs, create custom SNMP monitors, configure alerts, and monitor any SNMP-enabled network device from a single console.

Download CISCOSB-UDLD-MIB