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Table Of Contents
Pseudowire Emulation Edge-to-Edge MIBs for Ethernet Services
Prerequisites for the PWE3 MIBs
Restrictions for the PWE3 MIBs
Information About the PWE3 MIBs
How to Configure the PWE3 MIBs
Setting Up AToM Circuits Across a Network
Verifying the PWE3 MIBs Configuration
Configuration Examples for the PWE3 MIBs
Pseudowire Emulation Edge-to-Edge MIBs for Ethernet Services
The Pseudowire Emulation Edge-to-Edge (PWE3) MIBs for Ethernet Services provide Simple Network Management Protocol (SNMP) support within an Any Transport over Multiprotocol Label Switching (AToM) infrastructure emulating Ethernet services over packet switched networks (PSNs). The PWE3 MIBs include the CISCO-IETF-PW-MIB (PW-MIB), the CISCO-IETF-PW-MPLS-MIB (PW-MPLS-MIB), and the CISCO-IETF-PW-ENET-MIB (PW-ENET-MIB).
Feature History for the PWE3 MIBs
Finding Support Information for Platforms and Cisco IOS Software Images
Use Cisco Feature Navigator to find information about platform support and Cisco IOS software image support. Access Cisco Feature Navigator at http://www.cisco.com/go/fn. You must have an account on Cisco.com. If you do not have an account or have forgotten your username or password, click Cancel at the login dialog box and follow the instructions that appear.
Contents
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Prerequisites for the PWE3 MIBs
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Restrictions for the PWE3 MIBs
•
Information About the PWE3 MIBs
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How to Configure the PWE3 MIBs
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Configuration Examples for the PWE3 MIBs
Prerequisites for the PWE3 MIBs
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SNMP must be installed and enabled on the label switch routers (LSRs).
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MPLS must be enabled on the LSRs.
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Pseudowires must be configured with Ethernet access circuits. (For more detailed information, see the Any Transport over MPLS feature module.)
Restrictions for the PWE3 MIBs
This implementation of the PWE3 MIBs is limited to read-only (RO) permission for MIB objects except for the cpwVcUp and cpwVcDown notification enable object, cpwVcUpDownNotifEnable, which, for purposes of this release, has been extended to be writable by the SNMP agent.
•
The following tables in the PW-MIB are not supported in this release:
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cpwVcPerfCurrentTable
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cpwVcPerIntervalTable
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The following objects in the PW-MPLS-MIB are not supported in this release:
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cpwVcMplsOutboundIndexNext
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cpwVcMplsInboundIndexNext
•
The following tables in the PW-ENET-MIB are not supported in this release:
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cpwVcEnetMplsPriMappingTable
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cpwVcEnetStatsTable
Information About the PWE3 MIBs
To configure the PWE3 MIBs, you need to understand the following concepts:
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MIB Tables in the PW-MPLS-MIB
•
MIB Tables in the PW-ENET-MIB
What is a Pseudowire
A pseudowire is a point-to-point connection between pairs of provider edge (PE) routers (Figure 1). Its primary function is to emulate services like Ethernet over an underlying core MPLS network through encapsulation into a common MPLS format. By encapsulating services into a common MPLS format, a pseudowire allows carriers to converge their services to an MPLS network.
Figure 1 Sample Pseudowire Topology
PWE3 MIBs Architecture
The PWE3 MIBs architecture shown in Figure 2 categorizes three groups of MIBs that when used together, provide a complete picture of the emulated service; the native transport, which carries the service across the core network; and the relationship between the two.
Figure 2 PWE3 MIBs Architecture
The architecture is modular in nature, in that once deployed, new emulated service MIB modules or additional transport MIB modules simply "plug in" to or extend the existing infrastructure rather than require a new and unique one. This allows you to build management applications without the concern of a new service requiring the deployment of a completely new management strategy. Since the architecture is in essence a generalized association mechanism between existing service and transport MIB modules, it should be noted that the native MIB modules work in the absence of the associated PWE3-specific MIBs. The advantage is that if a PWE3-specific MIB has not yet been deployed in Cisco IOS software, which associates a service or transport with pseudowires, these MIB modules can still be queried. However, the only drawback is that the association with the pseudowire are absent. For example, although the PWE3 Frame Relay (CISCO-IETF-PW-FR-MIB) and the Asynchronous Transfer Mode (CISCO-IETF-PW-ATM) MIBs are not available in this implementation, you may still see entries in the corresponding native service MIB modules such as the Frame Relay Forum, Internet Engineering Task Force (IETF) standard and Cisco proprietary Frame Relay MIB modules, as well as the ATM Forum and Cisco proprietary ATM MIB modules.
When the corresponding PWE3-specific MIB modules are implemented in the future, you will be able to see those pseudowire associations at that time.
Components and Functions
The PWE3 MIBs have the following components and functions:
•
PW-MIB (the pseudowire MIB)
This MIB binds the PW-MPLS-MIB and the PW-ENET-MIB together, and provides status of the pseudowire emulation by using counters for monitoring and configuration of services, statistics, and notifications by using the SNMP protocol.
•
PW-MPLS-MIB (the pseudowire MPLS MIB)
This MIB provides managed objects that can be used by a network manager to monitor pseudowire emulation MPLS services, such as MPLS-Traffic Engineering (TE)-PSN and MPLS-non-TE-PSN, by using the SNMP protocol.
•
PW-ENET-MIB (the pseudowire Ethernet services MIB)
This MIB provides managed objects that can be used by a network manager to monitor pseudowire emulation Ethernet services by using the SNMP protocol.
MIB Tables in the PW-MIB
The PW-MIB consists of the following tables:
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cpwVcTable (Table 1)—Contains high-level generic parameters related to virtual circuit (VC) creation. This table is implemented as read only and is indexed by the cpwVcIndex, which uniquely identifies a singular connection. A row in this table represents an emulated virtual connection. This table is used for all VC types.
•
cpwVcPerfTotalTable (Table 2)—Provides per-VC performance information from the VC start time. This table is indexed by the cpwVcIndex.
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cpwVcIdMappingTable (Table 3)—Provides reverse mapping of the existing VCs based on VC type and VC ID ordering. This table is typically useful for element manager software (EMS) ordered query of existing VCs. This table is indexed by cpwVcIdMappingVcType, cpwVcIdMappingVcID, cpwVcIdMappingPeerAddrType and cpwVcIdMappingPeerAddr. This table is implemented as read only.
•
cpwVcPeerMappingTable (Table 4)—Provides reverse mapping of the existing VCs based on VC type and VC ID ordering. This table is typically useful for EMS ordered query of existing VCs. This table is indexed by cpwVcPeerMappingPeerAddrType, cpwVcPeerMappingPeerAddr, cpwVcPeerMappingVcType, and cpwVcPeerMappingVcID. This table is implemented as read only.
cpwVcTable
Table 1 lists the cpwVcTable objects and their descriptions.
cpwVcPerfTotalTable
Table 2 lists the cpwVcPerfTotalTable objects and their descriptions.
cpwVcIdMappingTable
Table 3 lists the cpwVcIdMappingTable objects and their descriptions.
cpwVcPeerMappingTable
Table 4 lists the cpwVcPeerMappingTable objects and their descriptions.
MIB Tables in the PW-MPLS-MIB
The PW-MPLS-MIB consists of the following tables:
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cpwVcMplsTable (Table 5)—Specifies information for the VC to be carried over an MPLS PSN. This table is indexed on cpwVcIndex.
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cpwVcMplsOutboundTable (Table 6)—Associates VCs using an MPLS PSN with the outbound MPLS tunnels toward the PSN or the physical interface in case of the VC only. A row in this table represents a link between PW VCs that require MPLS tunnels and an MPLS tunnel toward the PSN. This table is indexed by the cpwVcIndex and an additional index that is not supported in this implementation; consequently, its value is 1. The operator creates at least one entry in this table for each PW VC that requires an MPLS PSN. This implementation does not support the VC only case or the cpwVcMplsOutboundIndex.
•
cpwVcMplsInboundTable (Table 7)—Associates VCs using an MPLS PSN with the inbound MPLS tunnels for packets coming from the PSN, if such association is desired mainly for security reasons. A row in this table represents a link between PW VCs that require MPLS tunnels and an MPLS tunnel for packets arriving from the PSN. This table is indexed by the set of indexes used to identify the VC, cpwVcIndex and an additional index that is not supported in this implementation; consequently, its value is 1. An entry is created in this table either automatically by the local agent or manually by the operator when strict mode is required. This table points to the appropriate MPLS MIB. For MPLS-TE, the four variables relevant to the indexing of an MPLS TE tunnel are set. This implementation does not support the VC only case or the cpwVcMplsInboundIndex.
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cpwVcMplsNonTeMappingTable (Table 8)—Maps an inbound or outbound tunnel to a VC in non-TE applications. A row in this table represents the association between a PW VC and its non-TE MPLS outer tunnel. An application can use this table to retrieve quickly the PW carried over a specific non-TE MPLS outer tunnel. This table in indexed by the XC index for the MPLS non-TE tunnel and the direction of the VC in the specific entry. The same table is used in both inbound and outbound directions, but in a different row for each direction. If the inbound association is not known, no rows should exist for it. Rows are created by the local agent when all the association data is available for display.
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cpwVcMplsTeMappingTable (Table 9)—Maps an inbound or outbound tunnel to a VC in MPLS-TE applications. A row in this table represents the association between a PW VC and its MPLS-TE outer tunnel. An application can use this table to retrieve quickly the PW carried over specific a TE MPLS outer tunnel. This table in indexed by the four indexes of a TE tunnel, the direction of the VC specific entry, and the VcIndex. The same table is used in both inbound and outbound directions, but a different row for each direction. If the inbound association is not known, no rows should exist for it. Rows are created by the local agent when all the association data is available for display. This table shows mappings between pseudowires and the xconnect index for non-TE outer tunnel or index.
cpwVcMplsTable
Table 5 lists the cpwVcMplsTable objects and their descriptions.
cpwVcMplsOutboundTable
Table 6 lists the cpwVcMplsOutboundTable objects and their descriptions.
cpwVcMplsInboundTable
Table 7 lists the cpwVcMplsInboundTable objects and their descriptions.
cpwVcMplsNonTeMappingTable
Table 8 lists the cpwVcMplsNonTeMappingTable objects and their descriptions.
cpwVcMplsTeMappingTable
Table 9 lists the cpwVcMplsTeMappingTable objects and their descriptions.
MIB Tables in the PW-ENET-MIB
The PW-ENET-MIB consists of the following table:
•
cpwVcEnetTable (Table 10)—Provides Ethernet port mapping and VLAN configuration for each Ethernet emulated virtual connection. This table is indexed on cpwVcIndex, which uniquely identifies a singular connection. The second level index for this table is cpwVcEnetPwVlan, which indicates VLANs on this VC. This table is used only for Ethernet VC types—ethernetVLAN, ethernet, or ethernet virtual private LAN service (VPLS), and is implemented as read-only.
cpwVcEnetTable
Table 10 lists the cpwVcEnetTable objects and their descriptions.
Objects
The PWE3 MIBs represent an ASN.1 notation reflecting specific components of the pseudowire services. The MIBs enable a network management application using SNMP to GET this information for display. The MIBs support the standard GETNEXT and GETBULK functionality, but do not support configuration capabilities (via SET) in the current implementation.
Scalar Objects
The PWE3 MIBs contain the following supported scalar object:
•
cpwVcUpDownNotifEnable—This object reflects the configuration of the cpwVcUp and cpwVcDown notifications. If either of the notifications is configured via the command line interface (CLI), then this object has a value of true(1). If this object is set via SNMP to true(1), then it enables the emission of both the cpwVcUp and cpwVcDown notifications; if the object is set via SNMP to false(2), these notifications are not emitted.
Note
cpwVcUpDownNotifEnable can be set only if RW is configured for snmp-server community string [view view-name] [ro] [number].
The PWE3 MIBs contain the following unsupported scalar objects:
•
cpwVcIndexNext—This object is used to indicate the next cpwVcIndex value when adding rows to the cpwVcTable.
•
cpwVcNotifRate—This object indicates the rate at which cpwVcUp/Down notifications can be issued from the device.
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cpwVcMplsOutboundIndexNext—This object contains an appropriate value to be used for cpwVcMplsOutboundIndex when creating entries in the cpwVcMplsOutboundTable. The value 0 indicates that no unassigned entries are available. To obtain the cpwVcMplsOutboundIndex value for a new entry, the manager issues a management protocol retrieval operation to obtain the current value of this object. After each retrieval, the agent should modify the value to the next unassigned index, however the agent MUST NOT assume such retrieval will be done for each row created.
•
cpwVcMplsInboundIndexNext—This object contains an appropriate value to be used for cpwVcMplsInboundIndex when creating entries in the cpwVcMplsInboundTable. The value 0 indicates that no unassigned entries are available. To obtain the cpwVcMplsInboundIndex value for a new entry, the manager issues a management protocol retrieval operation to obtain the current value of this object. After each retrieval, the agent should modify the value to the next unassigned index, however the agent MUST NOT assume such retrieval will be done for each row created.
Notifications
The cpwVcUp and cpwVcDown notifications in the PW-MIB indicate when the operStatus values for a range of PW VCs have changed state.
The definition of these objects in the PW-MIB indicates that events of the same type, either up or down, must be able to be correlated into ranges. The implementation of these notifications does not do any of this correlation. A notification is generated for each individual VC that has an operational state change if that notification is enabled. A notification does not signal an operational state change for a group of VCs as described in the MIB.
Benefits
The PWE3 MIBs provide the ability to manage pseudowire emulation edge-to-edge by providing MPLS-related information about the service and a mechanism to monitor the Ethernet access circuits.
How to Configure the PWE3 MIBs
This section contains the following procedures:
•
Enabling the SNMP Agent (required)
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Setting Up AToM Circuits Across a Network (required)
•
Verifying the PWE3 MIBs Configuration (optional)
Enabling the SNMP Agent
Perform this task to enable the SNMP agent.
SUMMARY STEPS
1.
enable
2.
show running-configuration
3.
configure terminal
4.
snmp-server community string [view view-name] [ro] [number]
5.
end
6.
write memory
DETAILED STEPS
Setting Up AToM Circuits Across a Network
For detailed information, see the Any Transport over MPLS feature module.
Verifying the PWE3 MIBs Configuration
Perform a MIB walk using your SNMP management tool on cpwVcMIB, cpwVcMplsMIB, and cpwVcEnetMIB to verify that the PW-MIB, the PW-MPLS-MIB, and the PW-ENET-MIB objects are populated correctly.
Note
This release supports SNMPv1 and SNMPv2c.
Configuration Examples for the PWE3 MIBs
This section provides the following configuration examples:
PWE3 MIB: Examples
In the following example, the configuration permits any SNMP manager to access all objects with read-only permissions using the community string public.
Router# configure terminalEnter configuration commands, one per line. End with CNTL/Z.Router(config)# snmp-server community public ro
Note
There is no explicit way to configure the PWE3 MIBs. However, for information on AToM configuration tasks and examples, see the Any Transport over MPLS feature module.
There are notifications specific to the PWE3 MIBs. For detailed information on the commands used to configure them, see the "Command Reference" section.
Additional References
The following sections provide references related to the PWE3 MIBs.
Related Documents
Related Topic Document TitleSNMP commands
Cisco IOS Configuration Fundamentals and Network Management Command Reference, Release 12.3
SNMP configuration
"Configuring SNMP Support" chapter in the Cisco IOS Configuration Fundamentals and Network Management Configuration Guide
SNMP Support for VPNs
EoMPLS configuration tasks
The "How to Configure Any Transport over MPLS" section in the Any Transport over MPLS feature module
Other documentation
"Pseudo Wire (PW) Management Information Base," Internet draft, February 2004 [draft-ietf-pwe3-pw-mib-04.txt]; Zelig, D., Nadeau, T.D., Danenberg, D. and Mantin, S.
"Ethernet Pseudo Wire (PW) Management Information Base," Internet draft, February 2004 [draft-pwe3-enet-mib-04.txt]; Zelig, D. and Nadeau, T.D.
"Pseudo Wire (PW) over MPLS PSN Management Information Base," Internet draft, February 2004 [draft-ietf-pwe3-pw-mpls-mib-05.txt]; Zelig, D., Nadeau, T.D., Danenberg, D., Mantin, S. and Malis, A.
"Definitions for Textual Conventions and OBJECT-IDENTITIES for Pseudo-Wires Management," Internet draft, February 2003 [draft-ietf-pwe3-pw-tc-mib-04.txt]; Nadeau, T.D., Danenberg, D., Zelig, D.and Malis, A.
Note
For information on using SNMP MIB features, see the appropriate documentation for your network management system.
Standards
Standards TitleNo new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature.
—
MIBs
RFCs
Technical Assistance
Command Reference
This section documents revised commands. All other commands used with this feature are documented in the Cisco IOS Release 12.3 command reference publications.
snmp-server enable traps
To enable a label switch router (LSR) to send Simple Network Management Protocol (SNMP) notifications or informs to an SNMP host, use the snmp-server enable traps command in global configuration mode. To disable notifications or informs, use the no form of this command.
snmp-server enable traps [notification-type] [notification-option]
no snmp-server enable traps [notification-type] [notification-option]
Syntax Description
Defaults
If you issue this command on an LSR without specifying any notification-type keywords, the default behavior of the LSR is to enable all notification types controlled by the command (some notification types cannot be controlled by means of this command).
Command Modes
Global configuration
Command History
Usage Guidelines
To configure an LSR to send SNMP LDP notifications, you must issue at least one snmp-server enable traps command on the router.
To configure an LSR to send either notifications (traps) or informs to a designated network management station (NMS), you must issue the snmp-server host command on that device, using the keyword (traps or informs) that suits your purposes.
If you issue the snmp-server enable traps command without keywords, all SNMP notification types are enabled on the LSR. If you issue this command with specific keywords, only the notification types associated with those particular keywords are enabled on the LSR.
The snmp-server enable traps command is used in conjunction with the snmp-server host command. You use the latter command to specify the NMS host (or hosts) targeted as the recipient(s) of the SNMP notifications generated by SNMP-enabled LSRs in the network. To enable an LSR to send such notifications, you must issue at least one snmp-server host command on the LSR.
Examples
In the following example, the router is enabled to send all notifications to the host specified as myhost.cisco.com. The community string is defined as public.
Router(config)# snmp-server enable trapsRouter(config)# snmp-server host myhost.cisco.com publicIn the following example, the router is enabled to send Frame Relay and environmental monitor notifications to the host specified as myhost.cisco.com. The community string is defined as public.
Router(config)# snmp-server enable traps frame-relayRouter(config)# snmp-server enable traps envmon temperatureRouter(config)# snmp-server host myhost.cisco.com publicIn the following example, notifications are not sent to any host. BGP notifications are enabled for all hosts, but the only notifications enabled to be sent to a host are ISDN notifications (which are not enabled in this example).
Router(config)# snmp-server enable traps bgpRouter(config)# snmp-server host bob public isdnIn the following example, the router is enabled to send all inform requests to the host specified as myhost.cisco.com. The community string is defined as public.
Router(config)# snmp-server enable trapsRouter(config)# snmp-server host myhost.cisco.com informs version 2c publicIn the following example, HSRP MIB notifications are sent to the host specified as myhost.cisco.com. The community string is defined as public.
Router(config)# snmp-server enable hsrpRouter(config)# snmp-server host myhost.cisco.com traps version 2c public hsrpIn the following example, pseudowire up traps are enabled:
Router(config)# snmp-server enable traps pw vc upIn the following example, pseudowire down traps are enabled:
Router(config)# snmp-server enable traps pw vc downRelated Commands
Command DescriptionSpecifies the intended recipient of an SNMP notification (that is, the designated NMS workstation in the network).
snmp-server host
To specify a network management station (NMS) in the network as the intended recipient of Simple Network Management Protocol (SNMP) notifications or informs, use the snmp-server host command in global configuration mode. To disable the configuration of the NMS as intended recipient, use the no form of this command.
snmp-server host host-addr [vrf vrf-name] [traps | informs] [version {1 | 2c | 3 [auth | noauth |
priv]}] community-string [udp-port port] [notification-type]no snmp-server host host-addr [traps | informs]
Syntax Description
host-addr
Specifies the name or the IP address of the host NMS workstation on which the SNMP agent is running. The specified NMS thus serves as the recipient of SNMP notifications or informs.
vrf vrf-name
(Optional) Specifies the name of the Virtual Private Network (VPN) routing/forwarding instance (VRF) for which the NMS is to receive SNMP notifications or informs.
traps
(Optional) Sends SNMP notifications to the specified NMS host. This is the default of the snmp-server host command.
informs
(Optional) Sends SNMP informs to the specified NMS host.
version
(Optional) Indicates the SNMP version to be used in sending LDP notifications or informs to the NMS host. Version 3 is the most secure, because it allows packet encryption by means of the priv keyword (below). If you use the version keyword, you must also specify one of the following arguments:
•
1—SNMPv1. This option is not available when you are using the informs keyword.
•
2c—SNMPv2c.
•
3—SNMPv3. The following optional arguments can be used with the version 3 keyword:
–
auth—Enables Message Digest 5 (MD5) and Secure Hash Algorithm (SHA) packet authentication.
–
noauth—Indicates the noAuthNoPriv security level. This argument is the default if the [auth | noauth | priv] keyword argument is not specified.
–
priv—Enables Data Encryption Standard (DES) packet encryption (also called privacy encryption).
community-string
The community string, functioning much like a password, is sent with the notification or informs operation. Although you can set this string using the snmp-server host command by itself, we recommend that you define this string using the snmp-server community command before you use the snmp-server host command.
udp-port port
User Datagram Protocol (UDP) port number of the NMS host to which SNMP notifications or informs are to be sent. The default UDP port number is 162.
notification-type
(Optional) Specifies the particular type of SNMP notifications or informs to be sent to the NMS host. If no notification type is specified, all applicable SNMP notifications or informs are sent. One or more of the following can be specified as a keyword in this command:
•
bgp—Sends Border Gateway Protocol (BGP) state change notifications.
•
config—Sends configuration notifications.
•
dspu—Sends downstream physical unit (DSPU) notifications.
•
entity—Sends entity MIB modification notifications.
•
envmon—Sends Cisco enterprise-specific environmental monitor notifications when a specified system environmental threshold is exceeded.
•
frame-relay—Sends Frame Relay notifications.
•
hsrp—Sends Hot Standby Routing Protocol (HSRP) notifications.
•
isdn—Sends ISDN notifications.
•
llc2—Sends Logical Link Control, Type 2 (LLC2) notifications.
•
mpls-ldp—Sends notifications about status changes in LDP sessions. This keyword (including a hyphen) is seen as one word, enabling you to specify multiple keywords in the snmp-server host command (if you delimit each keyword with a space). The same parameter in the snmp-server enable traps command is specified as mpls ldp (including a space), which results in two words in the notification-type and notification-option parameters in the snmp-server enable traps command. A two-word parameter is consistent with other MPLS commands.
•
mpls-traffic-eng—Sends notifications indicating status changes in label distribution tunnels. This keyword (including hyphens) is seen as one word, enabling you to specify multiple keywords in the snmp-server host command (if you delimit each keyword with a space). The same parameter in the snmp-server enable traps command is specified as mpls traffic-eng (including a space and a hyphen), which results in two words in the notification-type and notification-option parameters in the snmp-server enable traps command. A two-word parameter is consistent with other MPLS commands.
•
pw-vc—Sends pseudowire (PW) virtual circuit (VC) notifications.
•
repeater—Sends standard repeater (hub) notifications.
•
rsrb—Sends remote source-route bridging (RSRB) notifications.
•
rsvp—Sends Resource Reservation Protocol (RSVP) notifications.
•
rtr—Sends SA Agent (Response Time Reporter [RTR]) notifications.
•
sdlc—Sends Synchronous Data Link Control (SDLC) notifications.
•
sdllc—Sends SDLC Logical Link Control (SDLLC) notifications.
•
snmp—Sends SNMP notifications (as defined in RFC 1157).
•
stun—Sends serial tunnel (STUN) notifications.
•
syslog—Sends system error message (Syslog) notifications. You can specify the level of messages to be sent using the logging history level command.
notification-type (continued)
•
tty—Sends Cisco enterprise-specific notifications when a TCP connection terminates.
•
x25—Sends X.25 event notifications.
Defaults
This command is disabled by default, in which case, no SNMP notifications are sent.
If you enter this command without keywords, the default is to send all notification types to the NMS host. No informs are sent to the host.
If no version keyword is specified, the default is Version 1. Issuing the no snmp-server host command without keywords disables notifications, but not informs, to the NMS host. To disable informs, use the no snmp-server host informs command.
Note
If the community-string is not defined if you use the snmp-server community command prior to you issuing the snmp-server host command, the default form of the snmp-server community command is automatically inserted into the configuration. The password (community-string) used for this automatic configuration of the snmp-server community is the same as the one specified in the snmp-server host command. This is the default behavior for Cisco IOS Release 12.0(3) and later.
Command Modes
Global configuration
Command History
Usage Guidelines
To configure a label switch router (LSR) to send SNMP notifications to an NMS, you must enter at least one snmp-server host command on the LSR.
If you issue the snmp-server host command without keywords, all SNMP notification types are enabled for the specified NMS host. If you issue this command with specific keywords, only the notification types associated with those particular keywords are enabled for the NMS host.
To specify multiple NMS hosts as recipients of SNMP notifications or informs, you must issue a separate snmp-server host command for each targeted NMS host. You can specify multiple notification types in the command for each NMS.
When multiple snmp-server host commands are issued for the same NMS host and notification type (trap or inform request), each succeeding command overwrites the previous command. For example, if you issue an snmp-server host inform command for an NMS host and then issue another snmp-server host inform command for the same NMS host, the second command overrides the first command.
The snmp-server host command is used in conjunction with the snmp-server enable command. You use the snmp-server enable command to specify which SNMP notifications are to be sent globally. For an NMS host to receive most SNMP notifications, at least one snmp-server enable command and the snmp-server host command for that NMS host must be enabled on the LSR.
Examples
If you want to configure a unique SNMP community string for notifications, but you want to prevent SNMP polling access with this particular string, the configuration should include an access-list. In the following example, the community string is named comaccess and the access list is numbered 10:
Router(config)# snmp-server community comaccess ro 10Router(config)# snmp-server host 172.20.2.160 comaccessRouter(config)# access-list 10 deny anyIn the following example, SNMP notifications are sent to the NMS host specified as myhost.cisco.com. The community string is defined as comaccess.
Router(config)# snmp-server enable trapsRouter(config)# snmp-server host myhost.cisco.com comaccess snmpIn the following example, SNMP and the Cisco environmental monitor (envmon) enterprise-specific notifications are sent to the NMS host identified by IP address 172.30.2.160:
Router(config)# snmp-server enable trapsRouter(config)# snmp-server host 172.30.2.160 public snmp envmonIn the following example, the LSR is enabled to send all notifications to the SNMP host identified as myhost.cisco.com. The community string is defined as public.
Router(config)# snmp-server enable trapsRouter(config)# snmp-server host myhost.cisco.com publicIn the following example, notifications are not sent to any SNMP host. The BGP notifications are enabled for all hosts, but only the ISDN notifications are sent to the host NMS.
Router(config)# snmp-server enable traps bgpRouter(config)# snmp-server host bob public isdnIn the following example, the LSR is enabled to send all inform requests to the NMS host specified as myhost.cisco.com. The community string is defined as public.
Router(config)# snmp-server enable trapsRouter(config)# snmp-server host myhost.cisco.com informs version 2c publicIn the following example, Hot Standby Router Protocol (HSRP) MIB notifications are sent to the NMS host specified as myhost.cisco.com. The community string is defined as public.
Router(config)# snmp-server enable hsrpRouter(config)# snmp-server host myhost.cisco.com traps version 2c public hsrpIn the following example, the community name is defined as public and SNMP pw-vc-specific notifications are sent to the NMS host identified by IP address 172.19.192.50:
Router(config)# snmp-server host 172.19.192.50 public pw-vcRelated Commands
Command DescriptionEnables the LSR on which this command is executed to send SNMP notifications to a designated NMS host.
Glossary
CE router—customer edge router. A router that is part of a customer network and that interfaces to a provider edge (PE) router.
encapsulation—Wrapping of data in a particular protocol header. For example, Ethernet data is wrapped in a specific Ethernet header before network transit. Also, when bridging dissimilar networks, the entire frame from one network is simply placed in the header used by the data link layer protocol of the other network.
EoMPLS—Ethernet over Multiprotocol Label Switching (MPLS). A tunneling mechanism that allows a service provider to tunnel customer Layer 2 traffic though a Layer 3 MPLS network. EoMPLS is a point-to-point solution only. EoMPLS is also known Layer 2 tunneling.
IETF—Internet Engineering Task Force. A task force (consisting of more than 80 working groups) that is developing standards for the Internet and the IP suite of protocols.
LDP—Label Distribution Protocol. The protocol that supports MPLS hop-by-hop forwarding and the distribution of bindings between labels and network prefixes. The Cisco proprietary version of this protocol is the Tag Distribution Protocol (TDP).
LSP—label-switched path. A configured connection between two label switch routers (LSRs) in which label-switching techniques are used for packet forwarding; also a specific path through an MPLS network.
LSR—label switch router. A Multiprotocol Label Switching (MPLS) node that can forward native Layer 3 packets. The LSR forwards a packet based on the value of a label attached to the packet.
MIB—Management Information Base. A database of network management information that is used and maintained by a network management protocol such as Simple Network Management Protocol (SNMP). The value of a MIB object can be changed or retrieved by using SNMP commands, usually through a network management system. MIB objects are organized in a tree structure that includes public (standard) and private (proprietary) branches.
MPLS—Multiprotocol Label Switching. A switching method for the forwarding of IP traffic through the use of a label. This label instructs the routers and the switches in the network where to forward the packets based on preestablished IP routing information.
MTU—maximum transmission unit. Maximum packet size, in bytes, that a particular interface can handle.
NMS—network management system. System responsible for managing at least part of a network. An NMS is generally a reasonably powerful and well-equipped computer, such as an engineering workstation. NMSs communicate with agents to help keep track of network statistics and resources.
notification—A message sent by a Simple Network Management Protocol (SNMP) agent to a network management station, console, or terminal to indicate that a significant network event has occurred. See also trap.
OSPF—Open Shortest Path First. A link-state hierarchical Interior Gateway Protocol routing algorithm, derived from the IS-IS protocol. OSPF features include least-cost routing, multipath routing, and load balancing.
PE router—provider edge router. A router that is part of a service provider's network and is connected to a customer edge (CE) router.
primary tunnel—Tunnel whose LSP may be fast rerouted if there is a failure. Backup tunnels cannot be primary tunnels.
pseudowire—PW. A mechanism that carries the elements of an emulated service from one provider edge (PE) to one or more PEs over a packet switched network (PSN).
SNMP—Simple Network Management Protocol. A management protocol used almost exclusively in TCP/IP networks. SNMP provides a means for monitoring and controlling network devices, and for managing configurations, statistics collection, performance, and security.
trap—A message sent by an SNMP agent to a network management station, console, or terminal, indicating that a significant event occurred. Traps are less reliable than notification requests because the receiver does not send an acknowledgment when it receives a trap. The sender cannot determine if the trap was received.
tunnel—A secure communication path between two peers, such as routers.
Note
Refer to Internetworking Terms and Acronyms for terms not included in this glossary.
Copyright © 2004 Cisco Systems, Inc. All rights reserved.
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