Cisco Active Network Abstraction Reference Guide, 3.7.2
Ethernet OAM

Table Of Contents

Ethernet OAM

Technology Description

CFM

Link OAM

Ethernet LMI

Information Model Objects (IMOs)

CFM Service

CFM Maintenance Domain

CFM Maintenance Point

CFM Maintenance Endpoint

CFM Maintenance Association

CFM Maintenance Intermediate Point

OAM Data

OAM Remote Data

Ethernet LMI

Device EVC

UNI Properties

UNI Interfaces

ELMI Interfaces

Vendor-Specific Inventory and IMOs

Service Alarms


Ethernet OAM


This chapter describes the level of support that Cisco ANA provides for Ethernet Operations, Administration, and Management (OAM), as follows:

Technology Description

Information Model Objects (IMOs)

Vendor-Specific Inventory and IMOs

Service Alarms

Technology Description

This section provides the following Ethernet OAM technology descriptions:

CFM

Link OAM

Ethernet LMI

CFM

Ethernet Connectivity Fault Management (CFM) is an end-to-end, per-service-instance Ethernet layer operations, administration, and maintenance (OAM) protocol. It includes proactive connectivity monitoring, fault verification, and fault isolation for large Ethernet MANs and WANs. "End-to-end" can mean PE-to-PE or CE-to-CE. A service can be identified as a service provider VLAN (S-VLAN) or an Ethernet Virtual Connection (EVC) service. Cisco ANA supports both

Cisco Proprietary Draft 1 (CFM D1) and Ethernet CFM IEEE 802.1ag Standard, using a a common IMO model.

Link OAM

Link OAM allows network operators to monitor and troubleshoot a single Ethernet link. It is an optional sublayer implemented in the Data Link Layer between the Logical Link Control (LLC) and MAC sublayers of the Open Systems Interconnect (OSI) model. You can monitor a link for critical events and, if needed, put a remote device into loopback mode for link testing. Link OAM also discovers unidirectional links, which are created when one transmission direction fails.

OAM information is conveyed in Slow Protocol frames (see Annex 57A) called OAM Protocol Data Units (OAMPDUs). OAMPDUs contain the appropriate control and status information used to monitor, test and troubleshoot OAM-enabled links. OAMPDUs traverse a single link, being passed between peer OAM entities, and as such, are not forwarded by MAC clients (e.g., bridges or switches).

Ethernet LMI

Ethernet Local Management Interface (Ethernet LMI) is a protocol that runs on the Provider Edge (PE) to Customer Edge (CE) UNI link and notifies the CE of connectivity status and configuration parameters of Ethernet services available on the CE port. Ethernet LMI interoperates with an OAM protocol, such as CFM, that runs within the provider network to collect OAM status.

Ethernet LMI provides information that enables autoconfiguration of customer edge (CE) devices and provides the status of Ethernet virtual connections (EVCs) for large Ethernet metropolitan-area networks (MANs) and WANs. Specifically, Ethernet LMI notifies a CE device of the operating state of an EVC and the time when an EVC is added or deleted. Ethernet LMI also communicates the attributes of an EVC and a user-network interface (UNI) to a CE device.

Information Model Objects (IMOs)

This section describes the following IMOs:

CFM Service (ICfmService)

CFM Maintenance Domain (IMaintenanceDomain)

CFM Maintenance Point (IMaintenancePoint)

CFM Maintenance Endpoints (IMaintenanceEndPoints)

CFM Maintenance Association (IMaintenanceAssociation)

CFM Maintenance Intermediate Point (IMaintenanceIntermediatePoint)

OAM Data (IOAMData)

OAM Remote Data (IOAMRemoteData)

UNI Properties (IUNIProperties)

Ethernet LMI (IEthernetLMI)

Device EVC (IDeviceEVC)

UNI Interfaces (IUNIInterfaces)

ELMI Interfaces (IELMIInterfaces)

CFM Service

The CFM Service object represents an instance of CFM enabled on a device.

Table 19-1 CFM Service (ICfmService)  

Attribute Name
Attribute Description
Scheme
Polling Interval

cacheSize

The CFM traceroute cache size used by the CFM service.

IpCore, Product

Configuration

maximumCacheSize

The CFM traceroute maximum cache size used by the CFM service.

IpCore, Product

Configuration

holdTime

The configured hold-time value used to indicate to the receiver the validity of traceroute and loopback messages transmitted by this device. The default is 2.5 times the transmit interval.

IpCore, Product

Configuration

version

The CFM version running on the device.

IpCore, Product

Configuration

maintenanceIntermedatePointsTable

An array of all the CFM Maintenance Intermediate Point objects configured on the device.

IpCore, Product

Configuration

maintenanceDomain

The CFM Maintenance Domain configured on the device.

IpCore, Product

Configuration


CFM Maintenance Domain

The CFM Maintenance Domain object represents an instance of a CFM management space used to manage and administer a network. A CFM management domain is owned and operated by a single entity and defined by the set of ports internal to it and at its boundary.

Table 19-2 CFM Maintenance Domain (IMaintenanceDomain)

Attribute Name
Attribute Description
Scheme
Polling Interval

name

The name of the management domain. This must be unique and cannot be used within a different maintenance level.

IpCore, Product

Configuration

level

The domain level (an integer in the range 0 to 7). Domain levels permit creation of a domain hierarchy. The larger the level value, the larger the domain. For instance, the costumer domain will have a level of 7, and the operator domain will have a level of 0.

IpCore, Product

Configuration

Id

The domain ID. Optional and may not be defined. When undefined, the domain name is used as the default value.

IpCore, Product

Configuration

maintenanceAssociation

A list of the domain's CFM Maintenance Associations. These are the associations represented by the service. In Cisco devices, the domain is mapped to a VLAN.

IpCore, Product

Configuration


CFM Maintenance Point

The CFM Maintenance Point object represents an instance of a CFM maintenance point configured on one or more of a device's interfaces.

Table 19-3 CFM Maintenance Point (IMaintenancePoint)  

Attribute Name
Attribute Description
Scheme
Polling Interval

macAddress

The MAC address on the interface on which the maintenance point is configured. In different interface modes, the MAC address may hold different values. For example, an inward facing interface uses the Bridge-Brain MAC address; an outward facing interface, such as a routed port, uses the port MAC address; and outward facing MEPs on port channels use the Bridge-Brain MAC address of the first member link. When port channel members change, the identities of outward facing MEPs do not have to change.

IpCore, Product

Configuration

Interface

A link to the interface on which the maintenance point is configured. This property includes all interface types that can be configured with CFM maintenance points.

IpCore, Product

Configuration


CFM Maintenance Endpoint

The CFM Maintenance Endpoint object represents an instance of a CFM Maintenance Endpoint (MEP),. Unlike MIPs, MEPs are associated by a CFM Maintenance Association (S-VLAN).

Table 19-4 CFM Maintenance Endpoints (IMaintenanceEndPoints)  

Attribute Name
Attribute Description
Scheme
Polling Interval

Id

The ID of the MEP (an integer from 1 and 8191). It identifies the MEP in CFM communications and to catalog CFM frames in the local CFM database. The MEP ID is meaningful throughout the CFM domain and through the maintenance association.

IpCore, Product

Configuration

Continuity Check Status

Current MEP status sent to other MEPs and MIPs via multicast CCMs (Unknown, MEP active, MEP inactive, MEP enabled, MEP disabled). CCMs are confined to a domain and S-VLAN.

IpCore, Product

Configuration

direction

Direction of the MEP (inward facing, outward facing). Inward facing means the MEP communicates through the Bridge Relay function and uses the Bridge-Brain MAC address. Outward facing means that the MEP communicates through the wire. Outward facing MEPs can be configured on routed ports and switch ports. A MIP configuration at a level higher than the level of the outward facing MEP is not required.

IpCore, Product

Configuration

cfmRemoteMaintenanceEndPoints

An array listing all the remote CFM MEPs that were discovered through this MEP. Properties for each remote MEP are used to establish CFM topology between CFM MEPs.

IpCore, Product

Configuration


CFM Maintenance Association

The CFM Maintenance Association object models a grouping of CFM Maintenance Endpoint.

Table 19-5 CFM Maintenance Association (IMaintenanceAssociation)  

Attribute Name
Attribute Description
Scheme
Polling Interval

name

The Association name.

IpCore, Product

Configuration

associationType

The Association type (Unknown, Bridge Domain VLAN, Bridge Domain, Port, Pseudowire).

IpCore, Product

Configuration

maximalMeps

The maximum number of MEPs that can be configured on the Maintenance Association.

IpCore, Product

Configuration

continuityCheckInterval

The configured time interval between continuity checks performed by the Maintenance Association's MEPs.

IpCore, Product

Configuration

continuityCheckEnable

Indicates whether continuity checking is enabled for the Association. CFM continuity checks are periodic heartbeat messages exchanged between the MEPs under the association. They allow MEPs to discover each other and CFM Maintenance Intermediate Points to discover the MEPs.

IpCore, Product

Configuration

crossCheckEnable

Indicates whether cross-checking is enabled for the Association. CFM cross-checking verifies that all endpoints of a service are operational. It is timer-driven and performed once.

IpCore, Product

Configuration

Direction

The direction of the association (up, down, unknown).

IpCore, Product

Configuration

Inner VLAN

The inner or customer VLAN ID.

IpCore, Product

Configuration

MaximalMeps

Maximum number of maintenance endpoints that can be configured on the maintenance association.

IpCore, Product

Configuration

bridge

Object Identifier of the bridge on which the association (VLAN) is configured.

IpCore, Product

Configuration

maintenanceEndPoints

An array of the CFM Maintenance Endpoint configured within the bounds of the CFM Maintenance Domain.

IpCore, Product

Configuration

RemoteMaintenanceEndPoints

Remote MEPs configured on other CFM-configured devices in the network. Each MEP can communicate with several remote MEPs.

IpCore, Product

Configuration


CFM Maintenance Intermediate Point

The CFM Maintenance Intermediate Point object represents a single instance of a CFM Maintenance Intermediate Point (MIP). Unlike MEPs, MIPs are not grouped by CFM Maintenance Associations (S-VLAN). Instead, they are grouped by CFM Maintenance Domain (using the Level parameter) and for all S-VLANs enabled or allowed on a port.

.

Table 19-6 CFM Maintenance Intermediate Point (IMaintenanceIntermediatePoint)  

Attribute Name
Attribute Description
Scheme
Polling Interval

level

The level defined for this MIP. This is the same as the Level parameter defined for CFM Maintenance Domains: An integer from 0 to 7, assigned to each MIP for the purpose of creating hierarchical relationships among MIPs. All CFM frames at a level lower than the level assigned to the MIP are stopped and dropped, independent of whether they originate from the wire or relay function. All CFM frames at a higher level than the MIP are forwarded, independent of whether they arrive from the wire or relay function.

IpCore, Product

Configuration

cfmInterface

The normalized name of the interface on which the MIP is configured.

IpCore, Product

Configuration

isAutocreated

Indicates whether this MIP was created automatically (true) or by entering properties manually using the command-line interface (CLI) (false).

IpCore, Product

Configuration

Vlans

A list of the VLANs in which this MIP participates. A MIP configured on an interface normally functions via maintenance domain (level) and for all S-VLANs enabled or allowed on that port. To limit its functionality, however, a CFM MIP can also be configured with a list of S-VLANs or associations.

IpCore, Product

Configuration

InnerVlans

A list of the inner VLANs in which this MIP participates. A CFM maintenance intermediate point configured on an interface functions per maintenance domain (level) and for all inner VLANs enabled or allowed on a port.

IpCore, Product

Configuration

macAddress

The MAC address that identifies the CFM entity (for example, bridge-brain MAC).

IpCore, Product

Configuration


OAM Data

The OAM Data object represents support and status of OAM functions on Ethernet-like interfaces.

.

Table 19-7 OAM Data (IOAMData)  

Attribute Name
Attribute Description
Scheme
Polling Interval

Admin Status

Used to enable and disable the OAM sublayer entity.

IpCore, Product

Configuration

Maximum PDU Rate

The maximum transmission and reception rate of OAM PDUs as part of the discovery process (packets per second).

IpCore, Product

Configuration

Minimum PDU Rate

The minimum transmission and reception rate of OAM PDUs as part of the discovery process (packets per second).

IpCore, Product

Configuration

Link Timeout

The time (in seconds) after which a device declares the OAM peer to be non-operational and resets its state machine.

IpCore, Product

Configuration

High Threshold Action

The action to be taken when a monitored error has been detected to have crossed a user-specified threshold.

IpCore, Product

Configuration

Link Fault Action

The action to be taken when loss of signal (link fault) is detected.

IpCore, Product

Configuration

Dying Gasp Action

Used to indicate unrecoverable event conditions that should be transmitted to the peer OAM entity.

IpCore, Product

Configuration

Critical Event Action

Used to signal an unspecified critical link event condition.

IpCore, Product

Configuration

Mode

The local client OAM sublayer entity configuration status, either active or passive controlling of the peer's OAM configurations.

IpCore, Product

Configuration

Unidirectional

Indicates whether the OAM local entity supports the transmission of OAMPDUs on links that are operating in unidirectional mode.

IpCore, Product

Configuration

Link Monitor

Indicates whether a mechanism is provided to support event notification that permits the inclusion of diagnostic information.

IpCore, Product

Configuration

Remote Loopback

Indicates whether data link layer frame-level loopback mode is supported.

IpCore, Product

Configuration

Port Status

The operational status of the local port.

IpCore, Product

Configuration

Loopback Status

Indicates the Ethernet OAM loopback status of this interface (no loopback, remote loopback, initiating loopback, terminating loopback, local loopback, unknown.)

IpCore, Product

Configuration

Remote Data

OAM provides a mechanism to detect the presence of an OAM sublayer at the remote DTE.

IpCore, Product

Configuration

Ethernet Port

OID of the Ethernet Port

IpCore, Product

Configuration


OAM Remote Data

The OAM Remote Data object consists of interface remote peer summarized OAM data.

.

Table 19-8 OAM Remote Data (IOAMRemoteData)  

Attribute Name
Attribute Description
Scheme
Polling Interval

MAC Address

The MAC address of the remote client.

IpCore, Product

Configuration

Vendor

The vendor name of the remote client.

IpCore, Product

Configuration

Mode

The remote client OAM sublayer entity configuration status, either active or passive controlling of the peer's OAM configurations.

IpCore, Product

Configuration

Unidirectional

Indicates whether the remote OAM entity supports the transmission of OAMPDUs on links that are operating in unidirectional mode

IpCore, Product

Configuration

Link Monitor

Indicates whether a mechanism is provided to support event notification that permits the inclusion of diagnostic information.

IpCore, Product

Configuration

Remote Loopback

Indicates whether data link layer frame-level loopback mode is supported.

IpCore, Product

Configuration


Ethernet LMI

The Ethernet LMI object contains the properties that control the Ethernet LMI protocol between the customer edge (CE) network element and the provider edge (PE) network element, on the PE-CE UNI link.It notifies the CE of connectivity status and configuration parameters of Ethernet services available on the CE port. Ethernet LMI interoperates with an OAM protocol, such as CFM, that runs within the provider network to collect OAM status. Such a service will exist once per context and per device. It contains ELMI Interfaces (IELMIInterfaces) and Device EVC (IDeviceEVC).

.

Table 19-9 Ethernet LMI (IEthernetLMI)  

Attribute Name
Attribute Description
Scheme
Polling Interval

ELMI Enabled State

Indicates whether or not the Ethernet LMI protocol is enabled on the interface.

IpCore, Product

Configuration

ELMI Mode

The Ethernet LMI mode, either CE or PE.

IpCore, Product

Configuration

ELMI Interfaces

The interfaces on which Ethernet LMI is configured.

IpCore, Product

Configuration

Device EVCs

The Ethernet Virtual Connections configured on the device.

IpCore, Product

Configuration


Device EVC

The Device EVC object represents a port-level point-to-point or multipoint-to-multipoint Layer 2 circuit. It is an end-to-end representation of a single instance of a Layer 2 service being offered by a provider to a customer. It embodies the different parameters on which the service is being offered. A service instance is the instantiation of an EVC on a given port on a given router.

.

Table 19-10 Device EVC (IDeviceEVC)  

Attribute Name
Attribute Description
Scheme
Polling Interval

EVC Name

The name of the EVC.

IpCore, Product

Configuration

EVC Status

The status of the EVC (Active, Partially Active, Inactive), The EVC status can be used by a customer edge (CE) device either to find an alternative path in to the service provider network or, in some cases, to revert to a backup path over Ethernet or over another alternative service such as Frame Relay or ATM.

IpCore, Product

Status

EVC Type

The type of EVC (Point-to-point, Multipoint-to-Multipoint).

IpCore, Product

Configuration

Maintenance Association

The CFM Maintenance Association which uniquely identifies a service profile within the Maintenance Domain.

IpCore, Product

Configuration

Configured Remote UNI Count

The number of configured remote UNIs.

IpCore, Product

Configuration

Active Remote UNI Count

The number of active remote UNIs.

IpCore, Product

Configuration

UNI Interfaces

The UNI interfaces configured for Ethernet LMI.

IpCore, Product

Configuration


UNI Properties

The UNI Properties object holds the properties for the user-network interface (UNI). This IMO is mapped to the UniProperties in maps.xml.

.

Table 19-11 UNI Properties (IUNIProperties)  

Attribute Name
Attribute Description
Scheme
Polling Interval

UNI ID

The ID of the local user-network interface (UNI).

IpCore, Product

Configuration

Service Multiplexing Enabled

Returns a boolean value (true or false), to indicate whether service multiplexing is enabled. If more than one EVC is allowed, service multiplexing can be enabled (true).

IpCore, Product

Configuration

Bundling Enabled

Returns a boolean value (true or false) to indicate whether bundling is enabled. This is set as true when configuring the UNI by supporting only one EVC with one or more VLANs.

IpCore, Product

Configuration

Bundling Type

The Bundling service attribute enables two or more VLAN IDs to be mapped to a single EVC at a UNI. With bundling, the provider and subscriber must agree on the VLAN IDs used at the UNI and the mapping between each VLAN ID and a specific EVC. A special case of bundling is where every VLAN ID at the UNI interface maps to a single EVC. This service attribute is called all-to-one bundling.

IpCore, Product

Configuration


UNI Interfaces

The UNI Interfaces object represents the identity and the status of the UNI interfaces configured for Ethernet LMI.

.

Table 19-12 UNI Interfaces (IUNIInterfaces)  

Attribute Name
Attribute Description
Scheme
Polling Interval

UNI Status

The status of the UNI interface (up, down).

IpCore, Product

Status

UNI ID

The ID of the UNI.

IpCore, Product

Configuration

Interface Name

The name of the UNI.

IpCore, Product

Configuration

VLAN List

List of VLANs configured on the interface.

IpCore, Product

Configuration

LMI Link Status

The status of the LMI link (up, down).

IpCore, Product

Status

Interface OID

OID of the UNI.

N/A

N/A

Is UNI Local

Boolean UNI location, either local or remote.

IpCore, Product

Configuration


ELMI Interfaces

The ELMI Interfaces object holds the timers and counters used to assess and notify the CE of connectivity status and configuration parameters of Ethernet services available on the CE port.

.

Table 19-13 ELMI Interfaces (IELMIInterfaces)  

Attribute Name
Attribute Description
Scheme
Polling Interval

Interface Name

The name of the Ethernet LMI interface.

IpCore, Product

Configuration

Interface OID

The OID of the Ethernet LMI interface.

N/A

N/A

T391

Polling timer on the customer equipment. A polling timer sends status inquiries and records errors when status messages are not received. The range is from 5 to 30 seconds; the default is 10 seconds.

IpCore, Product

Configuration

T392

Polling verification timer for the metro Ethernet network or the timer to verify received status inquiries. The range is from 5 to 30 seconds, or 0 for disabled timer. The default is 15 seconds.

IpCore, Product

Configuration

N391

Event counter on the customer equipment. The counter polls the status of the UNI and all Ethernet virtual connections (EVCs). The range is from 1 to 65000; the default is 360.

IpCore, Product

Configuration

N393

Event counter for the metro Ethernet network. The range is from 1 to 10; the default is 4.

IpCore, Product

Configuration


Vendor-Specific Inventory and IMOs

There are no vendor-specific IMOs for this technology.

Service Alarms

The following alarms are supported for this technology:

CFM Domain Fault, page 40-15