# Terminal Monitoring

## 1. Function Overview

The terminal monitoring function checks the dead-or-alive state of specific terminals connected to the network switch.
The operating specifications for the terminal monitoring function are shown below.

- Terminal monitoring function overview
  Example of an L2MS manager with an L3 switch and an L2MS agent with an intelligent L2 PoE switch

As dead/alive monitoring methods, the following three types are provided.

1. Ping-based communication monitoring
   Ping (ICMP Echo request/reply) is issued at regular intervals to a terminal that has an IP address, and the terminal is determined to be down if there is no longer a response.
   The user can specify the ping response wait time and the number of failures before the connection is determined to be down.

2. Frame reception volume monitoring
   The frame reception volume is monitored at regular intervals for an individual port, and the terminal is determined to be down if the traffic falls below a specified volume.
   The user can specify the monitoring start threshold value and the threshold value at which a down condition is determined.
   Monitoring starts when the traffic exceeds the monitoring start threshold value, and a down condition is determined when the traffic falls below the down decision threshold.

3. LLDP reception interval monitoring
   The LLDP received at regular intervals by an individual port is monitored.
   Using the TTL which is a required item in the data portion of an LLDP packet, a down condition is determined if LLDP is not received within the TTL interval.

If monitoring detects a terminal fault (down), the following processing is automatically performed.

1. Alert display in the dashboard screen
   An indication that a fault (down) occurred for the monitored terminal is displayed in the alert screen of the dashboard.

2. Alert shown in LAN map screen

   - If the network switch monitoring the terminal is an L2MS manager
     LAN map notification and history information are used to indicate an error (down) occurred in a monitored terminal.

   - If the network switch monitoring the terminal is an L2MS agent
     The L2MS trap function is used to notify the L2MS manager.
     When the L2MS manager receives a notification, it uses the LAN map screen to indicate an error (down) occurred in a monitored terminal.

By the user’s choice, the following operations can be applied in parallel.

1. Fault detection notification by mail
   Notification that a monitored terminal has experienced a fault is sent to the desired recipient.

2. Notification to an SNMP manager
   A trap is sent to the SNMP manager specified by a command.

3. Restart of a terminal due to temporary stop of PoE supply
   If a down condition is detected on a port to which PoE power is being supplied, PoE power supply is temporarily turned off in an attempt to recover the monitored terminal.

## 2. Definition of Terms Used

None

## 3. Function Details

### 3.1. Monitoring by ping (ICMP Echo request/reply)

Specifications for terminal monitoring by ping are given below.

1. The interval of ICMP Echo request transmission from the network switch is fixed at 5 sec.

2. The ICMP Echo request that is transmitted has the following format.

   - As the ID field of the ICMP header, the unique ID assigned to each monitored terminal is specified.

   - As the sequence field of the ICMP header, a number that is sequentially incremented from 0 is specified.

3. The validity of the ICMP Echo reply is checked as follows.

   - Whether the ID field of the ICMP header contains the ID that was specified when sending the request

   - Whether the sequence field of the ICMP header contains the sequence number that was specified when sending the request

4. The wait time for ICMP Echo reply can be changed in the range of 1–60 sec, and the default is 2 sec.

5. The number of failures to receive the ICMP Echo reply from the monitored terminal after which a fault is determined can be set in the range of 1–100, and the default is twice.

6. Monitoring with ping can be done for a maximum of 64 units.

7. If sending a mail notification or SNMP trap is enabled, they are sent in the following cases.

   - When a terminal is detected to be down (sent every 24 hours while down)

   - When a terminal is detected to be up (sent when monitoring is started or restored)

### 3.2. Monitoring according to frame reception volume

The way in which this device monitors according to frame reception volume is described below.

1. At one-second intervals, the number of octets received at the port is referenced, and the number of octets received during one second is calculated.

   - All ports are the object of observation.

2. Using the number of octets received during one second and the link speed, the reception throughput (bps) and reception ratio (%) are calculated.

3. Monitoring according to frame reception volume starts when the monitoring start threshold value (bps) specified by the user is exceeded.

4. After monitoring has started, a fault (down) is detected if the volume falls below the down detection threshold value (bps) specified by the user.

5. If sending a mail notification or SNMP trap is enabled, they are sent in the following cases.

   - When a terminal is detected to be down

   - When a terminal is detected to be up (sent when monitoring is started or restored)

### 3.3. Monitoring with LLDP

1. Using the TTL which is a required item in the data portion of an LLDP frame, a down condition is determined if LLDP is not received within the TTL time.

2. Monitoring starts when an LLDP frame is first received.

3. This monitoring can be specified individually by port.

4. If sending a mail notification or SNMP trap is enabled, they are sent in the following cases.

   - When a terminal is detected to be down

   - When a terminal is detected to be up (sent when monitoring is started or restored)

   - When a terminal stopped LLDP functionality

## 4. Related Commands

This function does not support settings via commands.

## 5. Settings via the Web GUI

Terminal monitoring settings can be done from [Advanced settings]-[Terminal monitoring] of the Web GUI.
Details on the settings in each screen can be referenced via the Web GUI help.

### 5.1. Terminal monitoring top page

The top page of terminal monitoring is shown below.

- If you want to newly add a terminal for monitoring, press the New icon.

- If you want to change a currently-specified monitored terminal, press the [Setting] button in the list.
  If you want to delete a currently-specified monitored terminal, select the check box of that terminal, and press the [Delete] button.

- If you want to ascertain the current state of the monitored terminal for which you are making settings, press the [Update] button to acquire the latest state.

### 5.2. Adding or modifying a monitored terminal

The method for adding a new monitored terminal, or for making changes, is shown below for each method of monitoring.

1. Monitoring by ping

2. Frame reception volume monitoring

3. LLDP reception interval monitoring

   - Restart terminal by controlling PoE supply can be specified only for models that support PoE supply.

   - Use the traffic observation function when deciding the monitoring start threshold value and the down detection threshold value settings for frame reception volume monitoring.

   - If you want mail notification to be sent in the event of a fault, you must separately make mail notification settings.
     For details, refer to Technical reference: [Maintenance and operation functions] - [Mail notification] and to Web GUI help: [Management] - [Mail notification].

### 5.3. Checking the state of a monitored terminal

The state of a specified monitored terminal can be checked in the terminal monitoring gadget of the dashboard.

- For each monitored terminal, this shows the monitoring target, model name, monitoring type, and status.

- The following three states are shown as the state of the monitored terminal.

  - Idle : Monitoring is not yet being performed:

  - Up : The monitored terminal is operating correctly:

  - Down : The monitored terminal is not operating correctly:

- Point the mouse cursor above a status column to show the status for that monitored terminal.

- If you click the [Idle] , [Up], or [Down] button in the upper part of the dashboard, only the monitored terminals that are in the corresponding state are shown. (The [All] button shows terminals of all states.)

- If not even one monitor terminal is registered, the display indicates “No monitored terminals are registered.”

## 6. Points of Caution

None

## 7. Related Documentation

- Performance Observations

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