Network topology

Introduction

NetXMS server automatically creates and maintains network model on different layers. All necessary information taken from ARP cache, routing tables, and switch forwarding database of managed nodes. Topology data provided by CDP, LLDP, and NDP (SONMP) protocols also used in building network model. Having network model instantly available allows NetXMS users to perform various network topology tasks much faster and easier.

Requirements to build network topology:

  • All network equipment should be registered in NetXMS system
  • Equipment should response to SNMP
  • Equipment should have at least STP
  • There will be more information if equipment will have LLDP or CDP

Manual topology poll can be started on the network equipment to heave information about information availability.

Based on network topology network correlation is done. Network correlation reduce number of alerts and increase problem resolution speed.

Currently there are 3 states/events regarding connectivity:

  • down (event SYS_NODE_DOWN) - when server cannot contact the node and has no topology information for event correlation or it is really problem with that node
  • unreachable (SYS_NODE_UNREACHABLE) - when server knows that node cannot be contacted due to intermediate router/interface failure
  • up (SYS_NODE_UP) - when node is reachable

So when node becomes unreachable, either SYS_NODE_DOWN or SYS_NODE_UNREACHABLE event is generated, depending on root cause. But when node became reachable again, SYS_NODE_UP being generated.

How topology information is built

Find where node is connected

It is possible to find switch port where any given node is connected (sometimes called “connection point” in management console). To find out node’s connection point, right-click on node object, and select Find switch port in pop-up menu. Message box with search results will pop up, and if port is found, search results view will be opened (or updated if already open). Search results view looks like this:

_images/Cp_search_results.png

Columns have the following meaning:

Seq. Search result sequence number
Node Name of end node object
Interface Name of node’s interface object
MAC Interface’s MAC address
IP Interface’s IP address
Switch Name of switch node object
Port Name of interface object representing switch port
Type Connection type - direct or indirect. Direct connection type means that NetXMS server did not detect any other devices on same switch port, and most likely end node connected directly to the switch. Indirect means that some other devices was detected on same switch port. Virtual machines and virtual machine host will always be detected as indirect.

Find MAC address

It is possible to find location of any known MAC address in the network. To do this, select Tools ‣ Find MAC address. Results of a search will be displayed in the same results view. It is not necessary that node with given MAC address be managed by NetXMS server, but if it is, appropriate details will be displayed.

Find IP address

It is possible to find location of any known IP address in the network. To do this, select Tools ‣ Find IP address. Results of a search will be displayed in the same results view. It is not necessary that node with given IP address be managed by NetXMS server, but if it is, appropriate details will be displayed.