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LANforge Entity IDs

Goal: Gain a better understanding of LANforge Entity IDs (EIDs)

Every port, radio, virtual port, endpoint and connection in LANforge has an ID known as an EID. These are an internal notation that expresses the hierarchy of the physical and virtual objects managed by LANforge realm.

Ports, Endpoints and Connections are Entities

Entity IDs (EIDs) are a dotted-decimal phrase. It expresses the Shelf, Resource Number, Port or Connection number, and if it is an endpoint, it gains a fourth decimal. An example:  : EID
1        : shelf
  2      : resource
    8    : port
      4  : endpoint

For now, assume the shelf number will always be 1. The Resource number will refer to the LANforge machine ID as reported on the Status tab. The Port ID is only unique within a LANforge machine. The Port ID also refers to hardware in a machine: radios get a third decimal. The fourth decimal refers to either endpoints or connections.

Only Some LANforge Entities Generate Connection Data

While some items with port numbers, notably radios and ports, do not generate traffic. Endpoints generate traffic, and typically endpoints are transmitting to an opposite endpoint. The exception to this are multicast endpoints.

EIDs Express Hierarchy

From the dotted-decimal perspective:

The formatting of the decimals might or might not be zero-padded. The picture below should convey how a connection (Layer 3) relates to two endpoints, and two ports:

The exception is connections. Connections are numbered outside of this hierarchy.

Do I use EIDs in Scripts?

Usually not, for these reasons:

  1. EIDs are generated at LANforge manager start time, and might depend on the detection order of ports when the PCI bus on the host is enumerated at boot time.
  2. New EIDs can be created by appending one database to another on non-conflicting devices
  3. New devices can be hot-added to a LANforge resource, like a programmable attenuator or a USB-Ethernet adapter, generating new Port IDs.

In scripts, it is legal to reference port numbers, but not advised to store them between sessions. If you reference an EID, it should be from within your present LANforge session. If your resources tend to disappear off the network and return (you had a machine reboot) those EIDs are not guaranteed to return.

For ports, only the first two decimals (shelf and resource id) are actually stable across machine reboots.

If you look into the saved scenarios (in /home/lanforge/DB/DFLT) you will notice that ports, endpoints, and connections are refered to by name. Event though in the CLI Users's guide, where it states port number, use names in your scripts:

|        SHELF
|        |  RESOURCE
|        |  |  PORT
|        |  |  |
set_port 1  1  eth1 ....

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