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Layer 2 Topology(Applet)

The Layer 2 topology is drawn according to the bridge protocol and any of Link Layer Discovery Protocol (LLDP), Neighbor Discovery Protocol (NDP), Cisco Discovery Protocol (CDP), and Spanning Tree Protocol (STP). It displays the network structure and status information such as Layer 2 connections among devices on the subnet, link status, and device status.

The Layer 2 topology supports delayed deletion, which allows invalid Layer 2 links to be displayed as dotted lines in the topology for a specified time delay, and finally deletes the invalid lines when the delay expires.

The Multiple Spanning Tree Protocol (MSTP) topology is drawn automatically according to the spanning tree information of the devices. It shows the topology of each spanning tree, including device status and link status.

Operation Procedure

1. Click the Resource tab.
2. Select View Management > IP Topology in the navigation tree.
3. Double-click IP Topology in the topology navigation tree and then double-click a non-empty subnet in the IP topology page, or double-click a subnet in the topology navigation tree.

Functions

1. Delayed delete setting: Right-click on a blank area of the Layer 2 topology, and then select Delayed Delete Setting from the shortcut menu. With this function enabled, a deleted link remains on the topology until the specified lifetime is due.
2. View MSTP topology: Click on the toolbar of the topology, and select CIST or an instance in the area. Nodes or links not in the CIST or the instance are grayed out.
3. View MST details: Click on the toolbar of the topology.
4. Path Topology: Right-click on a blank area of the Layer 2 topology and then select Path Topology from the shortcut menu. In the dialog box that appears, type the source and destination IP addresses and click OK.

Precautions

• LLDP, NDP, CDP, or STP should be enabled in order to assure the Layer 2 topology more precisely and reduce the resource use.
• The Layer 2 topology requires SNMP to be enabled, and the MIBs related to 802.1d and 802.1q to be implemented.
• Two switches connected through a hub are in direct connection in the topology.
• The representation of a link becomes a dotted line when the MAC addresses of the nodes on both sides of the link are aged out. The link is finally removed from the topology when the specified lifetime is due.
• Changes to the lifetime for delayed deletion apply both to the links aged out after the changes and the links already existed.
• If the links in all the instances are blocked, the blocked links are marked in the Layer 2 topology. If the links in a certain MSTP instance are blocked, the blocked links are marked on one side in the MSTP topology.

Related Topics

• Layer 2 Topology