During the second phase of the discovery process, each imported router or switch is probed to identify MPLS, VPN, and (optional) BGP topology information. At the end of the probing, instances of MPLS-, VPN-, and BGP-specific objects are created in the MPLS Topology Server repository.

During this phase of the discovery process, the MPLS Topology Server creates instances of the classes that are identified in Initial topology added to the MPLS Topology Server repository.

Table 1. Initial topology added to the MPLS Topology Server repository

Class name

Description

1  The MPLS signaling and control plane is entirely separate from the VPN control plane.

MPLS objects

MPLSService

A logical object that is created for each device that is discovered in the managed MPLS network.

LSP table manager

(represents a collection of LSP table manager objects)

A collection of LSP table manager objects that hold the LSP-related information that is gathered from all of the PE and P devices in the managed MPLS network.

LdpProtocolEndpoint

(in the MPLS signaling and control plane) 1

A type of service access point for one end of a Label Distribution Protocol adjacency. It represents one of two LDP peers that are responsible for exchanging the MPLS labels for an LDP LSP. The LDP peers reside on PE or P devices that are one hop apart.

RsvpProtocolEndpoint

A type of service access point for one end of a Resource Reservation Protocol session. It represents one of two RSVP-TE peers that are responsible for exchanging the MPLS labels for a TE LSP or subLSP. The RSVP-TE peers reside on PE or P devices that may be multiple hops apart.

L2VPN common objects

ForwarderEndpoint

A type of service access point for each Forwarder logical interface. It terminates one end of a pseudowire connection and holds, from an endpoint's point of view, the status of the pseudowire connection.

L2VPN LDP-specific objects

LdpProtocolEndpoint

(in the VPN control plane) 1

A type of service access point for one end of a Label Distribution Protocol adjacency. It represents one of two LDP peers that are responsible for exchanging the virtual circuit identifiers (VC IDs) for an LDP-signaled L2VPN. The LDP peers reside on PE devices that may be multiple hops apart.

L2VPN BGP-specific objects

VRF

A VPN routing and forwarding instance, maintained by a PE device, that contains the routing information that defines a customer L2VPN site.

RouteTarget

A logical entity that identifies a set of customer VPN sites to which a PE device distributes routes. It is used to set up peering relationships between the VRF instances that belong to the same L2VPN.

L3VPN objects

VRF

A VPN routing and forwarding instance, maintained by a PE device, that contains the routing information that defines a customer L3VPN site.

RouteTarget

A logical entity that identifies a set of customer VPN sites to which a PE device distributes routes. It is used to set up peering relationships between the VRF instances that belong to the same L3VPN.

BGP objects

AutonomousSystem

A routing-protocol domain that consists of one or more devices that are running BGP services.

BGPService

A BGP protocol process that is running on a device.

BGPProtocolEndpoint

A type of service access point that is defined for each BGP physical interface on the BGP device.

The probing of topology is accomplished by using the drivers in the .import files, which are located in the BASEDIR/smarts/conf/mpls-t directory of the MPLS Management Suite installation area. Eleven representative .import files are:

  • DISCOVERY.import

  • DISCOVERY_CUSTOM.import

  • LSP.import

  • MPLSVPN.import

  • MBGP.import

  • CLI.import

  • CLI_ERX.import

  • CLI_ERX7.import

  • CLI_Huawei.import

  • CLI_IOX35.import

  • CLI_Juniper6.import

    The main drivers for SNMP and CLI discovery are identified in the DISCOVERY.import, LSP.import, MPLSVPN.import, MBGP.import, and CLI_xxx.import files. Custom drivers, also known as discovery hook scripts, are identified in the DISCOVERY_CUSTOM.import file.

    The main drivers perform preprocessing tasks (such as recording the time that discovery begins), launch the SNMP and CLI discovery, and perform postprocessing tasks.