CISCO-IETF-IP-FORWARD-MIB

All MIBs › CISCO-IETF-IP-FORWARD-MIB

Organization: Cisco Systems, Inc.

Last Updated: 2002-01-24

Category: Cisco Devices, Routing Protocols

Description: Cisco adaptation of the IETF IP forwarding table MIB for managing unicast and multicast route entries.

Start monitoring vendor-neutral, standards-based MIB, any SNMPv3-capable network device (SNMP engine identity/boot/clock status) 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.

What Is CISCO-IETF-IP-FORWARD-MIB?

CISCO-IETF-IP-FORWARD-MIB is Cisco's implementation of the IETF's IP Forwarding Table MIB concept (in the spirit of RFC 2096/RFC 4292), adapted to Cisco's own object naming to manage the device's CIDR-based multipath unicast and multicast IP routing table. It exposes the live routing/forwarding state of the device: each route's destination, prefix length, next hop, associated interface, route type, and a discard counter for routes that could not be forwarded. Its primary monitoring value is software-state visibility into the routing engine's health — a rising cInetCidrRouteDiscards count signals routing table lookup failures, and monitoring cInetCidrRouteNumber over time reveals route table growth, flapping, or exhaustion that can precede performance problems. As a Cisco adaptation of an IETF standard, it is explicitly dependent on and modeled after the IETF IP-Forward MIB framework and the INET-ADDRESS-MIB textual conventions it reuses for address typing. As a CISCO-IETF-IP-FORWARD-MIB reference, it is typically deployed on Cisco routers and multilayer switches wherever detailed CIDR/multipath route-table visibility is needed beyond the basic ipRouteTable.

IPNetwork Monitor allows you to monitor SNMP objects defined in CISCO-IETF-IP-FORWARD-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 router
Cisco multilayer switch

Monitoring Examples

An operator would poll cInetCidrRouteTable/cInetCidrRouteEntry to enumerate routes by cInetCidrRouteDest and cInetCidrRoutePfxLen, checking cInetCidrRouteNextHop and cInetCidrRouteIfIndex to verify traffic for a given prefix is taking the expected path. A steadily increasing cInetCidrRouteDiscards counter alongside a stable cInetCidrRouteNumber would indicate the router is receiving unroutable or malformed traffic rather than a routing table capacity problem.

What Can Be Monitored

total route count
route discards
route destination/prefix
next hop address
route type (multipath/CIDR)
outgoing interface per route

Imported Objects

From CISCO-SMI

ciscoExperiment

OBJECT-IDENTITY

From IANA-RTPROTO-MIB

IANAipRouteProtocol

From IF-MIB

InterfaceIndex

From INET-ADDRESS-MIB

InetAddress
InetAddressPrefixLength
InetAddressType
InetAutonomousSystemNumber

From SNMPv2-CONF

MODULE-COMPLIANCE
OBJECT-GROUP

From SNMPv2-SMI

Counter32
Gauge32
Integer32
IpAddress
MODULE-IDENTITY
OBJECT-TYPE
Unsigned32

From SNMPv2-TC

RowStatus

How to Use in IPNetwork Monitor

Example using cInetCidrRouteDiscards OID:

Select a Cisco router/multilayer switch (IP forwarding table) 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 cInetCidrRouteDiscards into the Find box to locate it in the OID tree, then select it and click OK. The number of routing entries which were chosen to be discarded even though they are valid. 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 Counter32-type OID, Value bounds is the most useful condition here — trigger an alert if the counter increases between polls, since a rising count of errors, failures, or discards often points to a real underlying problem. Click Finish to create the monitor; you can adjust any parameter later.

OIDs

OID symbolic	OID numeric	Type	Access	Description
I32 cInetCidrRouteAge	1.3.6.1.4.1.9.10.85.7.1.10	Integer32	read-only	The number of seconds since this route was last updated or otherwise determined to be correct. Note that no semantics of `too old' can be implied except through knowledge of the routing protocol by which the route was learned.
IP cInetCidrRouteDest	1.3.6.1.4.1.9.10.85.7.1.3	InetAddress	not-accessible	The destination IP address of this route. Any assignment (implicit or otherwise) of an instance of this object to a value x must be rejected if the bitwise logical-AND of x with the value of the mask formed from the corresponding instance of the cInetCidrRoutePfxLen object is not equal to x.
IPt cInetCidrRouteDestType	1.3.6.1.4.1.9.10.85.7.1.2	InetAddressType	not-accessible	The type of cInetCidrRouteDest. Only IPv4 and IPv6 addresses are expected.
C32 cInetCidrRouteDiscardsEx	1.3.6.1.4.1.9.10.85.8	Counter32	read-only	The number of routing entries which were chosen to be discarded even though they are valid. One possible reason for discarding such an entry could be to free-up buffer space for other routing entries.
cInetCidrRouteEntry	1.3.6.1.4.1.9.10.85.7.1		not-accessible	A particular route to a particular destination, under a particular policy.
NUM cInetCidrRouteIfIndex	1.3.6.1.4.1.9.10.85.7.1.7	InterfaceIndex	read-create	The ifIndex value which identifies the local interface through which the next hop of this route should be reached.
U32 cInetCidrRouteInstance	1.3.6.1.4.1.9.10.85.7.1.1	Unsigned32	not-accessible	The instance identifier of the (conceptual) routing table containing this route. This identifier may be used to represent multiple routing tables, type-of-service routing, scopes, or any other use of multiple tables. XXX This needs more discussion.
I32 cInetCidrRouteMetric1	1.3.6.1.4.1.9.10.85.7.1.12	Integer32	read-create	The primary routing metric for this route. The semantics of this metric are determined by the routing-protocol specified in the route's cInetCidrRouteProto value. If this metric is not used, its value should be set to -1.
I32 cInetCidrRouteMetric2	1.3.6.1.4.1.9.10.85.7.1.13	Integer32	read-create	An alternate routing metric for this route. The semantics of this metric are determined by the routing-protocol specified in the route's cInetCidrRouteProto value. If this metric is not used, its value should be set to -1.
I32 cInetCidrRouteMetric3	1.3.6.1.4.1.9.10.85.7.1.14	Integer32	read-create	An alternate routing metric for this route. The semantics of this metric are determined by the routing-protocol specified in the route's cInetCidrRouteProto value. If this metric is not used, its value should be set to -1.
I32 cInetCidrRouteMetric4	1.3.6.1.4.1.9.10.85.7.1.15	Integer32	read-create	An alternate routing metric for this route. The semantics of this metric are determined by the routing-protocol specified in the route's cInetCidrRouteProto value. If this metric is not used, its value should be set to -1.
I32 cInetCidrRouteMetric5	1.3.6.1.4.1.9.10.85.7.1.16	Integer32	read-create	An alternate routing metric for this route. The semantics of this metric are determined by the routing-protocol specified in the route's cInetCidrRouteProto value. If this metric is not used, its value should be set to -1.
IP cInetCidrRouteNextHop	1.3.6.1.4.1.9.10.85.7.1.6	InetAddress	not-accessible	On remote routes, the address of the next system en route; Otherwise, a zero-length string.
INE cInetCidrRouteNextHopAS	1.3.6.1.4.1.9.10.85.7.1.11	InetAutonomousSystemNumber	read-create	The Autonomous System Number of the Next Hop. The semantics of this object are determined by the routing-protocol specified in the route's cInetCidrRouteProto value. When this object is unknown or not relevant its value should be set to zero.
IPt cInetCidrRouteNextHopType	1.3.6.1.4.1.9.10.85.7.1.5	InetAddressType	not-accessible	The address type of inetCidrRouteNextHop. Must be the same as that of cInetCidrRouteDestType, or unknown if there is no next hop.
G32 cInetCidrRouteNumber	1.3.6.1.4.1.9.10.85.6	Gauge32	read-only	The number of current cInetCidrRouteTable entries that are not invalid.
ADR cInetCidrRoutePfxLen	1.3.6.1.4.1.9.10.85.7.1.4	InetAddressPrefixLength	not-accessible	Indicate the number of leading one bits which form the mask to be logical-ANDed with the destination address before being compared to the value in the cInetCidrRouteDest field. Any assignment (implicit or otherwise) of an instance of this object to a value x must be rejected if the bitwise logical-AND of the mask formed from x with the value of the corresponding instance of the cInetCidrRouteDest object is not equal to cInetCidrRouteDest.
IAN cInetCidrRouteProto	1.3.6.1.4.1.9.10.85.7.1.9	IANAipRouteProtocol	read-only	The routing mechanism via which this route was learned. Inclusion of values for gateway routing protocols is not intended to imply that hosts should support those protocols.
ROW cInetCidrRouteStatus	1.3.6.1.4.1.9.10.85.7.1.17	RowStatus	read-create	The row status variable, used according to row installation and removal conventions.
cInetCidrRouteTable	1.3.6.1.4.1.9.10.85.7		not-accessible	This entity's IP Routing table.
INT cInetCidrRouteType	1.3.6.1.4.1.9.10.85.7.1.8	INTEGER	read-create	The type of route. Note that local(3) refers to a route for which the next hop is the final destination; remote(4) refers to a route for which the next hop is not the final destination. Routes which do not result in traffic forwarding or rejection should not be displayed even if the implementation keeps them stored internally. reject(2) refers to a route which, if matched, discards the message as unreachable and returns a notification (e.g. ICMP error) to the message sender. This is used in some protocols as a means of correctly aggregating routes. blackhole(5) refers to a route which, if matched, discards the message silently.
cInetForwardCidrRouteGroup	1.3.6.1.4.1.9.10.85.5.1.4			The IP version independent CIDR Route Table.
I32 cIpCidrRouteAge	1.3.6.1.4.1.9.10.85.4.1.8	Integer32	read-only	The number of seconds since this route was last updated or otherwise determined to be correct. Note that no semantics of `too old' can be implied except through knowledge of the routing protocol by which the route was learned.
IP cIpCidrRouteDest	1.3.6.1.4.1.9.10.85.4.1.1	IpAddress	read-only	The destination IP address of this route. This object may not take a Multicast (Class D) address value. Any assignment (implicit or otherwise) of an instance of this object to a value x must be rejected if the bitwise logical-AND of x with the value of the corresponding instance of the cIpCidrRouteMask object is not equal to x.
cIpCidrRouteEntry	1.3.6.1.4.1.9.10.85.4.1		not-accessible	A particular route to a particular destination, under a particular policy.
I32 cIpCidrRouteIfIndex	1.3.6.1.4.1.9.10.85.4.1.5	Integer32	read-create	The ifIndex value which identifies the local interface through which the next hop of this route should be reached.
OID cIpCidrRouteInfo	1.3.6.1.4.1.9.10.85.4.1.9	OBJECT IDENTIFIER	read-create	A reference to MIB definitions specific to the particular routing protocol which is responsible for this route, as determined by the value specified in the route's cIpCidrRouteProto value. If this information is not present, its value should be set to the OBJECT IDENTIFIER { 0 0 }, which is a syntactically valid object identifier, and any implementation conforming to ASN.1 and the Basic Encoding Rules must be able to generate and recognize this value.
IP cIpCidrRouteMask	1.3.6.1.4.1.9.10.85.4.1.2	IpAddress	read-only	Indicate the mask to be logical-ANDed with the destination address before being compared to the value in the cIpCidrRouteDest field. For those systems that do not support arbitrary subnet masks, an agent constructs the value of the cIpCidrRouteMask by reference to the IP Address Class. Any assignment (implicit or otherwise) of an instance of this object to a value x must be rejected if the bitwise logical-AND of x with the value of the corresponding instance of the cIpCidrRouteDest object is not equal to cIpCidrRouteDest.
I32 cIpCidrRouteMetric1	1.3.6.1.4.1.9.10.85.4.1.11	Integer32	read-create	The primary routing metric for this route. The semantics of this metric are determined by the routing-protocol specified in the route's cIpCidrRouteProto value. If this metric is not used, its value should be set to -1.
I32 cIpCidrRouteMetric2	1.3.6.1.4.1.9.10.85.4.1.12	Integer32	read-create	An alternate routing metric for this route. The semantics of this metric are determined by the routing-protocol specified in the route's cIpCidrRouteProto value. If this metric is not used, its value should be set to -1.
I32 cIpCidrRouteMetric3	1.3.6.1.4.1.9.10.85.4.1.13	Integer32	read-create	An alternate routing metric for this route. The semantics of this metric are determined by the routing-protocol specified in the route's cIpCidrRouteProto value. If this metric is not used, its value should be set to -1.
I32 cIpCidrRouteMetric4	1.3.6.1.4.1.9.10.85.4.1.14	Integer32	read-create	An alternate routing metric for this route. The semantics of this metric are determined by the routing-protocol specified in the route's cIpCidrRouteProto value. If this metric is not used, its value should be set to -1.
I32 cIpCidrRouteMetric5	1.3.6.1.4.1.9.10.85.4.1.15	Integer32	read-create	An alternate routing metric for this route. The semantics of this metric are determined by the routing-protocol specified in the route's cIpCidrRouteProto value. If this metric is not used, its value should be set to -1.
IP cIpCidrRouteNextHop	1.3.6.1.4.1.9.10.85.4.1.4	IpAddress	read-only	On remote routes, the address of the next system en route; Otherwise, 0.0.0.0.
I32 cIpCidrRouteNextHopAS	1.3.6.1.4.1.9.10.85.4.1.10	Integer32	read-create	The Autonomous System Number of the Next Hop. The semantics of this object are determined by the routing-protocol specified in the route's cIpCidrRouteProto value. When this object is unknown or not relevant its value should be set to zero.
G32 cIpCidrRouteNumber	1.3.6.1.4.1.9.10.85.3	Gauge32	read-only	The number of current ipCidrRouteTable entries that are not invalid. This object is deprecated in favor of cInetCidrRouteNumber and the cInetCidrRouteTable.
INT cIpCidrRouteProto	1.3.6.1.4.1.9.10.85.4.1.7	INTEGER	read-only	The routing mechanism via which this route was learned. Inclusion of values for gateway routing protocols is not intended to imply that hosts should support those protocols.
ROW cIpCidrRouteStatus	1.3.6.1.4.1.9.10.85.4.1.16	RowStatus	read-create	The row status variable, used according to row installation and removal conventions.
cIpCidrRouteTable	1.3.6.1.4.1.9.10.85.4		not-accessible	This entity's IP Routing table. This table has been deprecated in favor of the IP version neutral cInetCidrRouteTable.
I32 cIpCidrRouteTos	1.3.6.1.4.1.9.10.85.4.1.3	Integer32	read-only	The policy specifier is the IP TOS Field. The encoding of IP TOS is as specified by the following convention. Zero indicates the default path if no more specific policy applies. +-----+-----+-----+-----+-----+-----+-----+-----+ \| \| \| \| \| PRECEDENCE \| TYPE OF SERVICE \| 0 \| \| \| \| \| +-----+-----+-----+-----+-----+-----+-----+-----+ IP TOS IP TOS Field Policy Field Policy Contents Code Contents Code 0 0 0 0 ==> 0 0 0 0 1 ==> 2 0 0 1 0 ==> 4 0 0 1 1 ==> 6 0 1 0 0 ==> 8 0 1 0 1 ==> 10 0 1 1 0 ==> 12 0 1 1 1 ==> 14 1 0 0 0 ==> 16 1 0 0 1 ==> 18 1 0 1 0 ==> 20 1 0 1 1 ==> 22 1 1 0 0 ==> 24 1 1 0 1 ==> 26 1 1 1 0 ==> 28 1 1 1 1 ==> 30
INT cIpCidrRouteType	1.3.6.1.4.1.9.10.85.4.1.6	INTEGER	read-create	The type of route. Note that local(3) refers to a route for which the next hop is the final destination; remote(4) refers to a route for which the next hop is not the final destination. Routes which do not result in traffic forwarding or rejection should not be displayed even if the implementation keeps them stored internally. reject (2) refers to a route which, if matched, discards the message as unreachable. This is used in some protocols as a means of correctly aggregating routes.
I32 cIpForwardAge	1.3.6.1.4.1.9.10.85.2.1.8	Integer32	read-only	The number of seconds since this route was last updated or otherwise determined to be correct. Note that no semantics of `too old' can be implied except through knowledge of the routing protocol by which the route was learned.
cIpForwardCidrRouteGroup	1.3.6.1.4.1.9.10.85.5.1.3			The CIDR Route Table.
cIpForwardCompliance	1.3.6.1.4.1.9.10.85.5.2.1			The compliance statement for SNMPv2 entities which implement the ipForward MIB.
cIpForwardCompliance2	1.3.6.1.4.1.9.10.85.5.2.3			The compliance statement for systems which have routing tables. XXX is this right?
cIpForwardCompliances	1.3.6.1.4.1.9.10.85.5.2
cIpForwardConformance	1.3.6.1.4.1.9.10.85.5
IP cIpForwardDest	1.3.6.1.4.1.9.10.85.2.1.1	IpAddress	read-only	The destination IP address of this route. An entry with a value of 0.0.0.0 is considered a default route. This object may not take a Multicast (Class D) address value. Any assignment (implicit or otherwise) of an instance of this object to a value x must be rejected if the bitwise logical-AND of x with the value of the corresponding instance of the cIpForwardMask object is not equal to x.
cIpForwardEntry	1.3.6.1.4.1.9.10.85.2.1		not-accessible	A particular route to a particular destination, under a particular policy.
cIpForwardGroups	1.3.6.1.4.1.9.10.85.5.1
I32 cIpForwardIfIndex	1.3.6.1.4.1.9.10.85.2.1.5	Integer32	read-create	The ifIndex value which identifies the local interface through which the next hop of this route should be reached.
OID cIpForwardInfo	1.3.6.1.4.1.9.10.85.2.1.9	OBJECT IDENTIFIER	read-create	A reference to MIB definitions specific to the particular routing protocol which is responsible for this route, as determined by the value specified in the route's cIpForwardProto value. If this information is not present, its value should be set to the OBJECT IDENTIFIER { 0 0 }, which is a syntactically valid object identifier, and any implementation conforming to ASN.1 and the Basic Encoding Rules must be able to generate and recognize this value.
IP cIpForwardMask	1.3.6.1.4.1.9.10.85.2.1.2	IpAddress	read-create	Indicate the mask to be logical-ANDed with the destination address before being compared to the value in the cIpForwardDest field. For those systems that do not support arbitrary subnet masks, an agent constructs the value of the cIpForwardMask by reference to the IP Address Class. Any assignment (implicit or otherwise) of an instance of this object to a value x must be rejected if the bitwise logical-AND of x with the value of the corresponding instance of the cIpForwardDest object is not equal to cIpForwardDest.
I32 cIpForwardMetric1	1.3.6.1.4.1.9.10.85.2.1.11	Integer32	read-create	The primary routing metric for this route. The semantics of this metric are determined by the routing-protocol specified in the route's cIpForwardProto value. If this metric is not used, its value should be set to -1.
I32 cIpForwardMetric2	1.3.6.1.4.1.9.10.85.2.1.12	Integer32	read-create	An alternate routing metric for this route. The semantics of this metric are determined by the routing-protocol specified in the route's cIpForwardProto value. If this metric is not used, its value should be set to -1.
I32 cIpForwardMetric3	1.3.6.1.4.1.9.10.85.2.1.13	Integer32	read-create	An alternate routing metric for this route. The semantics of this metric are determined by the routing-protocol specified in the route's cIpForwardProto value. If this metric is not used, its value should be set to -1.
I32 cIpForwardMetric4	1.3.6.1.4.1.9.10.85.2.1.14	Integer32	read-create	An alternate routing metric for this route. The semantics of this metric are determined by the routing-protocol specified in the route's cIpForwardProto value. If this metric is not used, its value should be set to -1.
I32 cIpForwardMetric5	1.3.6.1.4.1.9.10.85.2.1.15	Integer32	read-create	An alternate routing metric for this route. The semantics of this metric are determined by the routing-protocol specified in the route's cIpForwardProto value. If this metric is not used, its value should be set to -1.
cIpForwardMultiPathGroup	1.3.6.1.4.1.9.10.85.5.1.2			IP Multipath Route Table.
IP cIpForwardNextHop	1.3.6.1.4.1.9.10.85.2.1.4	IpAddress	read-only	On remote routes, the address of the next system en route; Otherwise, 0.0.0.0.
I32 cIpForwardNextHopAS	1.3.6.1.4.1.9.10.85.2.1.10	Integer32	read-create	The Autonomous System Number of the Next Hop. When this is unknown or not relevant to the protocol indicated by cIpForwardProto, zero.
G32 cIpForwardNumber	1.3.6.1.4.1.9.10.85.1	Gauge32	read-only	The number of current cIpForwardTable entries that are not invalid.
cIpForwardOldCompliance	1.3.6.1.4.1.9.10.85.5.2.2			The compliance statement for SNMP entities which implement the ipForward MIB.
I32 cIpForwardPolicy	1.3.6.1.4.1.9.10.85.2.1.3	Integer32	read-only	The general set of conditions that would cause the selection of one multipath route (set of next hops for a given destination) is referred to as 'policy'. Unless the mechanism indicated by ipForwardProto specifies otherwise, the policy specifier is the IP TOS Field. The encoding of IP TOS is as specified by the following convention. Zero indicates the default path if no more specific policy applies. +-----+-----+-----+-----+-----+-----+-----+-----+ \| \| \| \| \| PRECEDENCE \| TYPE OF SERVICE \| 0 \| \| \| \| \| +-----+-----+-----+-----+-----+-----+-----+-----+ IP TOS IP TOS Field Policy Field Policy Contents Code Contents Code 0 0 0 0 ==> 0 0 0 0 1 ==> 2 0 0 1 0 ==> 4 0 0 1 1 ==> 6 0 1 0 0 ==> 8 0 1 0 1 ==> 10 0 1 1 0 ==> 12 0 1 1 1 ==> 14 1 0 0 0 ==> 16 1 0 0 1 ==> 18 1 0 1 0 ==> 20 1 0 1 1 ==> 22 1 1 0 0 ==> 24 1 1 0 1 ==> 26 1 1 1 0 ==> 28 1 1 1 1 ==> 30 Protocols defining 'policy' otherwise must either define a set of values which are valid for this object or must implement an integer-instanced policy table for which this object's value acts as an index.
INT cIpForwardProto	1.3.6.1.4.1.9.10.85.2.1.7	INTEGER	read-only	The routing mechanism via which this route was learned. Inclusion of values for gateway routing protocols is not intended to imply that hosts should support those protocols.
cIpForwardTable	1.3.6.1.4.1.9.10.85.2		not-accessible	This entity's IP Routing table.
INT cIpForwardType	1.3.6.1.4.1.9.10.85.2.1.6	INTEGER	read-create	The type of route. Note that local(3) refers to a route for which the next hop is the final destination; remote(4) refers to a route for which the next hop is not the final destination. Setting this object to the value invalid(2) has the effect of invalidating the corresponding entry in the cIpForwardTable object. That is, it effectively disassociates the destination identified with said entry from the route identified with said entry. It is an implementation-specific matter as to whether the agent removes an invalidated entry from the table. Accordingly, management stations must be prepared to receive tabular information from agents that corresponds to entries not currently in use. Proper interpretation of such entries requires examination of the relevant cIpForwardType object.
ciscoIetfIpForward	1.3.6.1.4.1.9.10.85			The MIB module for the management of CIDR multipath IP Routes.

RFC description

Cisco IETF-based MIB for managing IP packet forwarding information in a version-independent manner, originally designed for IPv6 support and based on RFC 2096 IP forwarding table specifications.

Start monitoring Cisco router/multilayer switch (IP forwarding table) 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 CISCO-IETF-IP-FORWARD-MIB