CISCO-NAT-CGN-EXT-MIB

All MIBs › CISCO-NAT-CGN-EXT-MIB

Organization: Cisco Systems, Inc.

Last Updated: 2014-04-03

Category: Cisco Devices, IP and Core Protocols, VPN and Security

Description: Manages Carrier-Grade NAT (CGN) address translation pools, mappings, and statistics on Cisco service provider routers.

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What Is CISCO-NAT-CGN-EXT-MIB?

CISCO-NAT-CGN-EXT-MIB extends the IETF draft NAT MIB to manage Carrier-Grade NAT (CGN, also called Large Scale NAT/LSN) address translation on Cisco service-provider routers, covering NAT44 and DS-Lite/NAT64 stateful translation. It exposes NAT instance configuration (service name, VRF, interface, behavior type, pooling type, port limits) and per-instance translation counters. Its monitoring value is centered on software/service-level status of the NAT function: tracking address-mapping/session counts and port-allocation behavior via cNatCgnCounterTable lets an operator detect port exhaustion or translation failures affecting subscriber traffic. It explicitly builds on and depends on the IETF draft-ietf-behave-nat-mib. It is deployed on Cisco service-provider edge/core routers performing large-scale IPv4 address sharing for broadband or mobile subscriber traffic. Engineers can download the CISCO-NAT-CGN-EXT-MIB file directly to load it into their MIB browser.

IPNetwork Monitor allows you to monitor SNMP objects defined in CISCO-NAT-CGN-EXT-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 service-provider router (Carrier-Grade NAT/CGN platform)

Monitoring Examples

An operator would poll cNatCgnInstanceTable (cNatCgnInstanceServiceName, cNatCgnInstanceVrf, cNatCgnInstanceInterface, cNatCgnInstanceProtocolPortLimit) to confirm a CGN instance's port-limit and pooling-type configuration matches policy. cNatCgnCounterTable entries reveal real-time translation/mapping counts per instance, and a counter approaching cNatCgnInstanceProtocolPortLimit would indicate imminent port exhaustion for a subscriber. cNatCgnInstanceProtocolPortBulkAllocControl shows whether bulk port allocation is enabled, which affects how quickly ports are consumed under load.

What Can Be Monitored

NAT instance configuration (VRF, interface, behavior type)
port allocation limit per subscriber
address mapping/translation counters
bulk port allocation status
NAT pooling type

Imported Objects

From CISCO-SMI

ciscoMgmt

OBJECT-IDENTITY

From NAT-MIB

NatBehaviorType
NatPoolingType
natCountersEntry
natInstanceEntry
natInstanceIndex

From SNMP-FRAMEWORK-MIB

SnmpAdminString

From SNMPv2-CONF

MODULE-COMPLIANCE
NOTIFICATION-GROUP
OBJECT-GROUP

From SNMPv2-SMI

Counter64
Gauge32
Integer32
MODULE-IDENTITY
NOTIFICATION-TYPE
OBJECT-TYPE
Unsigned32

From SNMPv2-TC

TEXTUAL-CONVENTION

How to Use in IPNetwork Monitor

Example using cNatCgnCounterSessionCreations OID:

Select a Cisco service-provider router (Carrier-Grade NAT/CGN) 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 cNatCgnCounterSessionCreations 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. This object indicates the number of sessions created since the instance is up. 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 a Counter64-type OID, Value bounds is the most useful condition here — trigger an alert if the counter increases sharply between polls relative to its normal baseline, since an unexpected spike often reflects a real change in traffic or activity. Click Finish to create the monitor; you can adjust any parameter later.

OIDs

OID symbolic	OID numeric	Type	Access	Description
ciscoNatCgnExtMIB	1.3.6.1.4.1.9.9.818			This MIB module extends the IETF draft NAT MIB available at http://tools.ietf.org/html/draft-ietf-behave-nat-mib-11 The extensions are intended to address the needs of the Carrier Grade NAT (CGN), also known as Large Scale NAT (LSN). GLOSSARY ========== Address mapping - is used to refer to association between a private IP to public IP (in case of NAT44 and DS Lite) or source IPv6 address to IPv4 address in case of NAT64 stateful application. Mapping - A mapping used to refer to a NAT translation record. It is a record held in memory that maps a private IP address and port to a public IP address and port. Subscriber - A subscriber is a record held in memory that provides IP address and other details of an end user device which has one or more mappings. Session - A session is a record maintained in memory that identifies a flow. The flow is uniquely identified by the source IPv4/IPv6 address, source port, translated IP address, translated source port, destination IPv4/IPv6 address and destination port. In to Out packet - A packet originating from a subscriber, with a private source address (or with an IPv6 address in case of NAT64), destined to a host with a public IP address. This packet needs NAT (or NAPT) service. Out to In packet - A packet originating from a host on the public Internet (or any host with a routable/public) source address, whose destination address is a mapped (translated) IP address. This packet needs reverse-NAT. Bulk port allocation - A NAT instance can be configured pre-allocate a range of contiguous ports instead of a single port. A mapping log record is created indicating the range of ports allocated to this subscriber. This is done in anticipation that the subscriber is likely to send packets that require more mappings to be created. For the subsequent mapping requests, one of the pre-allocated port is used and no additional log entries need to be created. This is a technique used to reduce the volume of translation record data.
ciscoNatCgnExtMIBNotifs	1.3.6.1.4.1.9.9.818.0
NTF cNatCgnNotifPortUsageWatermarkLow	1.3.6.1.4.1.9.9.818.0.1			The device generates this notification when the value of cNatCgnCounterCurrentPortAllocation becomes lower than or equal to the value of cNatCgnCounterPortUsageLowThreshold. The device will not generate notification if cNatCgnCounterPortUsageLowThreshold is set to zero.
NTF cNatCgnNotifPortUsageWatermarkLowClear	1.3.6.1.4.1.9.9.818.0.2			The device generates this notification when the value of cNatCgnCounterCurrentPortAllocation becomes higher than or equal to the value of cNatCgnCounterPortUsageClearLowThreshold and if cNatCgnNotifPortUsageWatermarkLow is already generated. The device will not generate notification if cNatCgnCounterPortUsageClearLowThreshold is set to zero.
NTF cNatCgnNotifPortUsageWatermarkHigh	1.3.6.1.4.1.9.9.818.0.3			The device generates this notification when the value of cNatCgnCounterCurrentPortAllocation becomes higher than or equal to the cNatCgnCounterPortUsageHighThreshold. The device will not generate notification if cNatCgnCounterPortUsageHighThreshold is set to zero.
NTF cNatCgnNotifPortUsageWatermarkHighClear	1.3.6.1.4.1.9.9.818.0.4			The device generates this notification when the value of cNatCgnCounterCurrentPortAllocation becomes lower than or equal to the value of cNatCgnCounterPortUsageClearLowThreshold and if cNatCgnNotifPortUsageWatermarkHigh is already generated. The device will not generate notification if cNatCgnCounterPortUsageClearHighThreshold is set to zero.
ciscoNatCgnExtMIBObjects	1.3.6.1.4.1.9.9.818.1
cNatCgnInstanceTable	1.3.6.1.4.1.9.9.818.1.1		not-accessible	This table lists the NAT instances configured on the device.
cNatCgnInstanceEntry	1.3.6.1.4.1.9.9.818.1.1.1		not-accessible	An entry describes a NAT instance configured on the device. The parameters include the type of the NAT instance and the important configuration elements.
NAT cNatCgnInstanceType	1.3.6.1.4.1.9.9.818.1.1.1.1	NatCgnInstanceType	read-write	This object specifies the type of the NAT instance. If the instance type is changed, the service-type attribute of the corresponding interfaces will also need to be changed.
STR cNatCgnInstanceServiceName	1.3.6.1.4.1.9.9.818.1.1.1.2	SnmpAdminString	read-write	This object specifies the CGN service name of this instance.
STR cNatCgnInstanceVrf	1.3.6.1.4.1.9.9.818.1.1.1.3	SnmpAdminString	read-write	This object specifies the name the VRF that is bringing in subscriber's traffic that needs to undergo NAT.
STR cNatCgnInstanceInterface	1.3.6.1.4.1.9.9.818.1.1.1.4	SnmpAdminString	read-write	This object specifies the name the interface that is bringing in subscriber's traffic that needs to undergo NAT. Typically either the cNatCgnInstanceVrf or cNatCgnInstanceInterface is needed to be configured, but not both.
NAT cNatCgnInstanceBehaviorType	1.3.6.1.4.1.9.9.818.1.1.1.5	NatBehaviorType	read-write	This object specifies the configured NAT mapping behavior for this instance.
NAT cNatCgnInstancePoolingType	1.3.6.1.4.1.9.9.818.1.1.1.6	NatPoolingType	read-write	This object specifies the configured NAT address pooling type for this instance.
U32 cNatCgnInstanceProtocolPortLimit	1.3.6.1.4.1.9.9.818.1.1.1.7	Unsigned32	read-write	This object specifies the configured protocol port limit. This is the maximum number of active mappings each subscriber can have at any given time. Value of zero means, it is unlimited.
U32 cNatCgnInstanceProtocolPortBulkAllocControl	1.3.6.1.4.1.9.9.818.1.1.1.8	Unsigned32	read-write	This object specifies the configured bulk port allocation size. Value of 0 means, bulk allocation is not applicable (or not supported). Value of 1 means, it is not enabled, that is, ports are allocated individually and not in bulk.
cNatCgnCounters	1.3.6.1.4.1.9.9.818.1.2
cNatCgnCounterTable	1.3.6.1.4.1.9.9.818.1.2.1		not-accessible	This table lists the counters of NAT instances in the device.
cNatCgnCounterEntry	1.3.6.1.4.1.9.9.818.1.2.1.1		not-accessible	An entry contains the additional statistics of a NAT instance.
C64 cNatCgnCounterSessionCreationsEx	1.3.6.1.4.1.9.9.818.1.2.1.1.1	Counter64	read-only	This object indicates the number of sessions created since the instance is up.
C64 cNatCgnCounterSessionRemovals	1.3.6.1.4.1.9.9.818.1.2.1.1.2	Counter64	read-only	This object indicates the number of sessions removed since the instance is up. The number of active sessions is equal to cNatCgnCounterSessionCreations - cNatCgnCounterSessionRemovals.
C64 cNatCgnCounterOutOfSessionDrops	1.3.6.1.4.1.9.9.818.1.2.1.1.3	Counter64	read-only	This object indicates the number of packets dropped because they required a new session entry to be created, however, there is no space to create new sessions.
C64 cNatCgnCounterSessionLimitDrops	1.3.6.1.4.1.9.9.818.1.2.1.1.4	Counter64	read-only	This object indicates the number of packets in either in to out or out to in direction dropped because of exceeding limit on session entries.
C64 cNatCgnCounterNoMappingEntryDrops	1.3.6.1.4.1.9.9.818.1.2.1.1.5	Counter64	read-only	This object indicates the number of packets in the out to in direction not translated because there was no mapping found.
C64 cNatCgnCounterSourceIPOutOfRangeDrops	1.3.6.1.4.1.9.9.818.1.2.1.1.6	Counter64	read-only	This object indicates the number of packets in the in to out direction not translated because source address was out of configured prefix or range. For NAT44 configured in predefined mode, NAT64 stateful or DS Lite, it could be drops due to source IP address not matching the configured prefix bits.
C64 cNatCgnCounterEndPointFilteringDrops	1.3.6.1.4.1.9.9.818.1.2.1.1.7	Counter64	read-only	This object indicates the number of packets in the out to in direction dropped because of end point dependent filtering policy. Note, the value of this object should be interpreted in conjunction with the value of cNatCgnInstanceBehaviorType. If the NAT instance is configured with endpointIndependent behavior, the instance is not supposed to filter or drop any packets based on the destination. In such case this counter could either be zero or could be the number of packets passed which would have otherwise be filtered and dropped if cNatCgnInstanceBehaviorType is set to addressDependent or addressAndPortDependent.
C64 cNatCgnCounterTCPSequenceDrops	1.3.6.1.4.1.9.9.818.1.2.1.1.8	Counter64	read-only	This object indicates the number of packets in the out to in direction dropped because TCP sequence check failed.
C64 cNatCgnCounterTCPMappingDrops	1.3.6.1.4.1.9.9.818.1.2.1.1.9	Counter64	read-only	This object indicates the number of TCP packets in the in to out direction dropped because a new mapping was required to be created, however TCP SYN flag was not set.
C64 cNatCgnCounterFragmentPktsInToOutDrops	1.3.6.1.4.1.9.9.818.1.2.1.1.10	Counter64	read-only	This object indicates the number of fragmented packets in the in to out direction dropped due to errors such as timed out waiting for first fragment or no space to hold the fragment.
C64 cNatCgnCounterFragmentPktsOutToInDrops	1.3.6.1.4.1.9.9.818.1.2.1.1.11	Counter64	read-only	This object indicates the number of fragmented packets in the out to in direction dropped due to errors such as timed out waiting for first fragment or no space to hold the fragment.
I32 cNatCgnCounterCurrentPortAllocation	1.3.6.1.4.1.9.9.818.1.2.1.1.12	Integer32	read-only	This object indicates the current average port allocation across all available public IP addresses applied to this NAT instance. When bulk allocation is enabled (that is, the value of cNatCgnInstanceProtocolPortBulkAllocControl is more than 1), this value will include all the ports pre-allocated in bulk (whether they are in use or not).
I32 cNatCgnCounterPortUsageLowThreshold	1.3.6.1.4.1.9.9.818.1.2.1.1.13	Integer32	read-write	This object specifies the low threshold in percentage of available public ports that are used up. The notification cNatCgnNotifPortUsageWatermarkLow is sent once the value of cNatCgnCounterAveragePortAllocation becomes less than or equal to this value. If this object is set to zero, the notification is not generated.
I32 cNatCgnCounterPortUsageClearLowThreshold	1.3.6.1.4.1.9.9.818.1.2.1.1.14	Integer32	read-write	This object specifies the clear low threshold in percentage of available public ports that are used up. The notification cNatCgnNotifPortUsageWatermarkLowClear is sent once the value of cNatCgnCounterAveragePortAllocation becomes more than or equal to this value. If this object is set to zero, the notification is not generated. Implementations must ensure that values of objects cNatCgnCounterPortUsageClearLowThreshold and cNatCgnCounterPortUsageLowThreshold remain consistent. For example, an implementation must respond with an inconsistentValue error if an attempt is made to set the the value of cNatCgnCounterPortUsageClearLowThreshold to be less than or equal to that of cNatCgnCounterPortUsageLowThreshold and vice versa.
I32 cNatCgnCounterPortUsageHighThreshold	1.3.6.1.4.1.9.9.818.1.2.1.1.15	Integer32	read-write	This object specifies the high threshold in percentage of available public ports that are used up. The notification cNatCgnNotifPortUsageWatermarkHigh is sent once the value of cNatCgnCounterAveragePortAllocation becomes higher than or equal to this value. If this field is set to zero, the notification is not generated.
I32 cNatCgnCounterPortUsageClearHighThreshold	1.3.6.1.4.1.9.9.818.1.2.1.1.16	Integer32	read-write	This object specifies the clear high threshold in percentage of available public ports that are used up. The notification cNatCgnNotifPortUsageWatermarkHighClear is sent once the value of cNatCgnCounterAveragePortAllocation becomes less than or equal to this value. If this object is set to zero, the notification is not generated. Implementations must ensure that values of objects cNatCgnCounterPortUsageClearHighThreshold and cNatCgnCounterPortUsageHighThreshold remain consistent. For example, an implementation must respond with an inconsistentValue error if an attempt is made to set the the value of cNatCgnCounterPortUsageClearHighThreshold to be more than or equal to that of cNatCgnCounterPortUsageHighThreshold and vice versa.
G32 cNatCgnCounterAverageBulkPortUsage	1.3.6.1.4.1.9.9.818.1.2.1.1.17	Gauge32	read-only	This object indicates the average percentage usage of ports pre-allocated in bulk. This value is valid only if the bulk allocation is configured. That is the value specified by the cNatCgnInstanceProtocolPortBulkAllocControl is more than 1. This value gives hints about effectiveness of bulk port allocation technique. A very low percentage of bulk port usage may suggest that, bulk allocation size be reduced. On the other hand, a value close to 100 may hint at increasing the bulk size to further reduce log data volume.
cNatCgnLogStatTable	1.3.6.1.4.1.9.9.818.1.2.2		not-accessible	This table lists the logging statistics of each NAT instance in the device.
cNatCgnLogStatEntry	1.3.6.1.4.1.9.9.818.1.2.2.1		not-accessible	An entry describes the logging related statistics of a NAT instance.
C64 cNatCgnLogStatMappingCreateRecords	1.3.6.1.4.1.9.9.818.1.2.2.1.1	Counter64	read-only	This object indicates the number of translation create records generated. It could be Netflow or Syslog records. It may not always necessarily be equal to number of mappings created (natMappingCreations of the NAT-MIB). If bulk allocation is enabled, this number could be much smaller than natMappingCreations. If the NAT mode is configured to be pre-defined or if logging is not configured, this could be zero.
C64 cNatCgnLogStatMappingDeleteRecords	1.3.6.1.4.1.9.9.818.1.2.2.1.2	Counter64	read-only	This object indicates the number of translation delete records generated. It could be Netflow or Syslog records. It may not always necessarily be equal to number of mappings deleted (natMappingRemovals of the NAT-MIB). If bulk allocation is enabled, this number could be much smaller than natMappingRemovals. If the NAT mode is configured to be pre-defined or if logging is not configured, this could be zero.
C64 cNatCgnLogStatSessionCreateRecords	1.3.6.1.4.1.9.9.818.1.2.2.1.3	Counter64	read-only	This object indicates the number of session create records generated. It could be Netflow or Syslog records. It may not always necessarily be equal to number of sessions created (cNatCgnCounterSessionCreations). If logging is not configured or if session logging is not configured, this could be zero.
C64 cNatCgnLogStatSessionDeleteRecords	1.3.6.1.4.1.9.9.818.1.2.2.1.4	Counter64	read-only	This object indicates the number of session delete records generated. It could be Netflow or Syslog records. It may not always necessarily be equal to number of sessions deleted (cNatCgnCounterSessionRemovals). If the logging is not configured or if session logging is not configured, this could be zero.
C64 cNatCgnLogStatNetflowPackets	1.3.6.1.4.1.9.9.818.1.2.2.1.5	Counter64	read-only	This object indicates the number of Netflow packets generated. This includes the packet which could not be sent out due to congestion or other reasons.
C64 cNatCgnLogStatNetflowPacketDrops	1.3.6.1.4.1.9.9.818.1.2.2.1.6	Counter64	read-only	This object indicates the number of Netflow packets which could not be sent out due to congestion or other errors within the CGN device. This does not include any drops along the way to the collector.
C64 cNatCgnLogStatSyslogPackets	1.3.6.1.4.1.9.9.818.1.2.2.1.7	Counter64	read-only	This object indicates the number of Syslog packets generated. This includes the packet which could not be sent out due to congestion or other reasons.
C64 cNatCgnLogStatSyslogPacketDrops	1.3.6.1.4.1.9.9.818.1.2.2.1.8	Counter64	read-only	This object indicates the number of Syslog packets which could not be sent out due to congestion or other errors within the CGN device. This does not include any drops along the way to the collector.
cNatCgnALGCountersTable	1.3.6.1.4.1.9.9.818.1.2.3		not-accessible	This table lists the application level gateway status and counters for each ALG type and for each NAT instance in the device.
cNatCgnALGCountersEntry	1.3.6.1.4.1.9.9.818.1.2.3.1		not-accessible	An entry describes status and counters of a specific ALG type for a specific NAT instance.
NAT cNatCgnALGType	1.3.6.1.4.1.9.9.818.1.2.3.1.1	NatCgnALGType	not-accessible	This object indicates the ALG type which together with natInstanceIndex uniquely identifies the set of counters being reported.
INT cNatCgnALGStatus	1.3.6.1.4.1.9.9.818.1.2.3.1.2	INTEGER	read-only	This object indicates the status of this ALG type for this NAT instance. notApplicable: This ALG type is not relevant to this NAT instance. unSupported: This ALG type is relevant to this NAT instance, however it is not supported. notEnabled: This ALG is supported on this NAT instance, however it is not enabled in the configuration. enabled: This ALG is enabled on this NAT instance. The rest of the objects of this entry are valid only if the cNatCgnALGStatus is set to enabled.
C64 cNatCgnALGMappingCreations	1.3.6.1.4.1.9.9.818.1.2.3.1.3	Counter64	read-only	This object indicates the number of mappings created for this ALG.
C64 cNatCgnALGMappingRemovals	1.3.6.1.4.1.9.9.818.1.2.3.1.4	Counter64	read-only	This object indicates the number of mappings removed which were created for this ALG. The number of active mappings for this ALG is equal to cNatCgnALGMappingCreations - cNatCgnALGMappingRemovals.
C64 cNatCgnALGUnsupportedErrors	1.3.6.1.4.1.9.9.818.1.2.3.1.5	Counter64	read-only	This object indicates the number of application level messages/packets which could not be processed as they used options which are not yet supported. This does not include messages/packets that did not conform to the protocol.
C64 cNatCgnALGProtocolErrors	1.3.6.1.4.1.9.9.818.1.2.3.1.6	Counter64	read-only	This object indicates the number of application level messages/packets which could not be processed as they did not conform to the protocol.
ciscoNatCgnExtMIBConform	1.3.6.1.4.1.9.9.818.2
cNatCgnMIBCompliances	1.3.6.1.4.1.9.9.818.2.1
cNatCgnModuleCompliance	1.3.6.1.4.1.9.9.818.2.1.1			This compliance statement specifies the minimal requirements an implementation must meet in order to claim full compliance with the definition of the CISCO-NAT-CGN-EXT-MIB.
cNatCgnMIBGroups	1.3.6.1.4.1.9.9.818.2.2
cNatCgnConfigGroup	1.3.6.1.4.1.9.9.818.2.2.1			This group contains objects describing basic configuration elements of NAT instances.
cNatCgnOptionConfigGroup	1.3.6.1.4.1.9.9.818.2.2.2			This group contains objects describing optional configuration elements of NAT instances.
cNatCgnCountersGroup	1.3.6.1.4.1.9.9.818.2.2.3			This group contains objects describing counters and thresholds.
cNatCgnSessionGroup	1.3.6.1.4.1.9.9.818.2.2.4			This group contains objects describing counters specific to session level tracking.
cNatCgnBulkAllocGroup	1.3.6.1.4.1.9.9.818.2.2.5			This group contains objects describing configuration and statistics specific to bulk port allocation.
cNatCgnNetflowLoggingGroup	1.3.6.1.4.1.9.9.818.2.2.6			This group contains objects describing counters of Netflow based logging.
cNatCgnSyslogLoggingGroup	1.3.6.1.4.1.9.9.818.2.2.7			This group contains objects describing counters of syslog based logging.
cNatCgnFragmentsGroup	1.3.6.1.4.1.9.9.818.2.2.8			This group contains objects describing fragment related counters.
cNatCgnALGCountersGroup	1.3.6.1.4.1.9.9.818.2.2.9			This group contains objects describing counters related to ALG processing.
cNatCgnServiceNameGroup	1.3.6.1.4.1.9.9.818.2.2.11			This group contains objects describing service related configuration elements
cNatCgnNotificationsGroup	1.3.6.1.4.1.9.9.818.2.2.15			This group contains notifications supporting NAT instances.

RFC description

Carrier Grade NAT (CGN/LSN) management for address mapping, sessions, and subscribers in large-scale NAT deployments.

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