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[EOL/EOE] [NSM] Topology discovery



Article ID: KB22648 KB Last Updated: 18 Oct 2020Version: 2.0
Note: A product listed in this article has either reached hardware End of Life (EOL) OR software End of Engineering (EOE).  Refer to End of Life Products & Milestones for the EOL, EOE, and End of Support (EOS) dates.
This article provides information about Topology Manager and Topology Discovery .
Information about Topology Manager and Topology Discovery

Topology Manager:

The NSM Topology Manager is a tool, provided in the NSM GUI, to discover and manage the physical topology of a network of devices connected to a Juniper EX-series switch. These include networking devices such as the J-series, M-series, MX-series, and EX-series; as well as ScreenOS and IDP devices, IP phones, desktops, printers, and servers. The Topology Manager also provides details about connections between a device and the EX-series switch.

How to  use the Topology Manager:

To use the Topology Manager, first add one or more EX-series switches to the device manager in NSM. You can then use an added device as a seed device in initiating a topology discovery.

Alternatively, if there are no devices added or managed in NSM, you can initiate a topology discovery by configuring preferred subnets. All the IP addresses in the included subnets range are discovered. So, you need to have either seed devices and/or preferred subnets to initiate topology discovery. You also need:
  • The management IP address of the EX-series switch, which acts as the seed IP address.

  • SNMP credentials:
    • For SNMP v1 and SNMP v2c: community string.

    • For SNMPv3: Username, security level, authentication type, privacy type, privacy password, and authentication password.

    • Enabled L2 protocols, such as LLDP and/or STP/RSTP in the switched network; as network discovery depends on these as well as the Address Forwarding Table information.

How to perform topology discovery by configuring preferred subnets:
  1. In the Configure panel of the NSM main navigation tree, go to Device Manager > Topology.

  2. From the Topology Manager toolbar, click Preferences (represented by red check marks).

  3. The Topology Manager Preferences window is displayed.
    1. Click the Refresh intervals sub-tab.

      Select Run topology discovery at regular intervals and specify the interval or the time of the day to run the discovery engine.

    2. Click the Preferred IP Subnets and ranges sub-tab.

      Add an IP subnet range in the Included IP subnets for discovery.

      The other settings you can specify for a topology discovery are the default SNMP credentials and, optionally, the subnets to be excluded. You can change these settings in the Default Credentials and Preferred SubNets sub-tabs of the Topology Manager Preferences window.

      Note: Topology Discovery supports only IPv4 addresses. IPv6based networks are not discovered.

  4. From the Topology Manager toolbar, click Discover (represented by a green arrow) to start the discovery process.

How does Topology Discovery Work:

NSM will send to SNMP a getBulkRequest and get-next-request to all the devices in the specified IP range, and receive the get response from the devices. NSM adds it to the Topology Manager. This can be seen by the following command:
#tcpdump -n -nn port 161 or port 162

How to view a network topology using the Topology Manager:
  1. In the Configure panel of the NSM main navigation tree, go to Device Manager > Topology.

  2. Click any of the following tabs for graphical or tabular views of the network topology:
    • Click the Topology Map tab and then select either SubNets or Groups to view the SubNets view or Groups view of the topology map in the main display area. Use the mini map tool in the topology map to focus on different areas in the topology map.

    • Click the Devices tab to view a list of networking devices in the topology.

    • Click the End Point Devices tab to view a list of end point devices such as IP phones, printers, computers, and wireless access points in the topology.

    • Click the Links tab to view the links among the devices in the topology. The Link table displays links between your network devices and network devices and end-point devices.

    • Click the Free Ports tab to view a list of EX-series switches and the available free ports (administratively down ports) on these switches.

How to Troubleshoot Topology Discovery:

The following errorlogs are for Topology Discovery:
  • /var/netscreen/DevSvr/errorlog/deviceservice.log

  • /var/netscreen/DevSvr/errorlog/topology_flow_log.log
Modification History:
2020-10-18: Tagged article for EOL/EOE.
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