RuggedCom RSG2488, Руководство пользователя

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Chapter 5
Setup and Configuration
RUGGEDCOM RSG2488
User Guide
172 Managing Network Discovery
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Figure 133: SNMP Access Form
1. Group Box 2. Security Model Box 3. Security Level Box 4. ReadViewName Box 5. WriteViewName Box
6. NotifyViewName Box 7. Apply Button 8. Delete Button 9. Reload Button
3. Click Delete .
Section 5.7
Managing Network Discovery
ROS supports the Link Layer Discovery Protocol (LLDP), a Layer 2 protocol for automated network discovery.
LLDP is an IEEE standard protocol, IEEE 802.11AB, which allows a networked device to advertise its own basic
networking capabilities and configuration. It can simplify the troubleshooting of complex networks and can be
used by Network Management Systems (NMS) to obtain and monitor detailed information about a network’s
topology. LLDP data are made available via SNMP (through support of LLDP-MIB).
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
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.
The following sections describe how to configure and manage network discovery, refer to the following:
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Section 5.7.1, “Configuring LLDP Globally”