Network Discovery Concepts; Link Layer Discovery Protocol (Lldp); Ruggedcom Discovery Protocol (Rcdp) - Siemens RUGGEDCOM ROS User Manual

Chapter 5
Setup and Configuration
• Section 5.8.2, "Configuring LLDP Globally"
• Section 5.8.3, "Configuring LLDP for an Ethernet Port"
• Section 5.8.4, "Enabling/Disabling RCDP"
• Section 5.8.5, "Viewing Global Statistics and Advertised System Information"
• Section 5.8.6, "Viewing Statistics for LLDP Neighbors"
• Section 5.8.7, "Viewing Statistics for LLDP Ports"
Section 5.8.1

Network Discovery Concepts

The following sections describe some of the concepts important to the implementation of network discovery in
ROS:
• Section 5.8.1.1, "Link Layer Discovery Protocol (LLDP)"
• Section 5.8.1.2, "RUGGEDCOM Discovery Protocol (RCDP)"
Section 5.8.1.1

Link Layer Discovery Protocol (LLDP)

LLDP is an IEEE standard protocol, IEEE 802.11AB, that allows a networked device to advertise its own basic
networking capabilities and configuration.
LLDP allows a networked device to discover its neighbors across connected network links using a standard
mechanism. Devices that support LLDP are able to advertise information about themselves, including their
capabilities, configuration, interconnections, and identifying information.
LLDP agent operation is typically implemented as two modules: the LLDP transmit module and LLDP receive
module. The LLDP transmit module, when enabled, sends the local device's information at regular intervals, in
IEEE 802.1AB standard format. Whenever the transmit module is disabled, it transmits an LLDPDU (LLDP data
unit) with a time-to-live (TTL) type-length-value (TLV) containing 0 in the information field. This enables remote
devices to remove the information associated with the local device in their databases. The LLDP receive module,
when enabled, receives remote devices' information and updates its LLDP database of remote systems. When
new or updated information is received, the receive module initiates a timer for the valid duration indicated by
the TTL TLV in the received LLDPDU. A remote system's information is removed from the database when an
LLDPDU is received from it with TTL TLV containing 0 in its information field.
NOTE
LLDP is implemented to keep a record of only one device per Ethernet port. Therefore, if there are
multiple devices sending LLDP information to a switch port on which LLDP is enabled, information
about the neighbor on that port will change constantly.
Section 5.8.1.2

RUGGEDCOM Discovery Protocol (RCDP)

RUGGEDCOM Discovery Protocol (RCDP) supports the deployment of ROS -based devices that have not been
configured since leaving the factory. ROS devices that have not been configured all have the default IP (Layer 3)
address. Connecting more than one of them on a Layer 2 network means that one cannot use standard IP-based
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RUGGEDCOM ROS
User Guide
Network Discovery Concepts