# What are the prerequisites for adding an IP SLA (VoIP/WAN RTT/Video) monitor?

[![IPSLA monitoring in OpManager: Video](https://www.manageengine.com/network-monitoring/images/webp/ipsla-violation-alert.webp)](https://www.youtube-nocookie.com/embed/ma1iF8g4cLI)

**WAN RTT:** The WAN RTT Monitor in OpManager works according to the ICMP echo operation. It monitors the end to end response time (Round Trip Time) between a Cisco router/switch and an IPv4/IPv6 destination device(s) and also helps in troubleshooting connectivity issues in a network.

**VoIP:** OpManager performs the UDP jitter operation to proactively monitor the VoIP quality between Cisco devices. The UDP jitter operation simulates continuous VoIP traffic to consistently monitor the voice quality scores between the source and the destination devices.

## Table of Contents

- [Prerequisites to add new monitors](https://www.manageengine.com/network-monitoring/how-to/prerequisites-for-IPSLA-monitor.html#add) (Add VOIP/WAN RTT monitors to OpManager)
- [Prerequisites to add existing monitor](https://www.manageengine.com/network-monitoring/how-to/prerequisites-for-IPSLA-monitor.html#fetch) (For retrieving monitors from the source device and adding them to OpManager)
- [IP SLA responder](https://www.manageengine.com/network-monitoring/how-to/prerequisites-for-IPSLA-monitor.html#responder)

## Prerequisites to add VOIP/WAN RTT monitors to OpManager

1. The source should be an IP SLA enabled Cisco device, added/discovered in OpManager.
2. SNMP credentials with 'Read' and 'Write' permissions should be properly configured and associated to the source device. OpManager supports SNMP v1/v2c for configuration and SNMP v1/v2c/v3 for data collection of an IP SLA monitor.
3. Destination device:
   - **a. WAN RTT:** The destination device(s) can be any networking device with a valid IP address that supports RFC 862 or Echo protocols or an IP SLA Responder enabled Cisco device.
   - **b. VoIP:** The destination device(s) should always be a Cisco device with IP SLA Responder enabled.

## Prerequisites for retrieving VOIP and WAN RTT monitors from the source device and adding them to OpManager:

**Note:** This is supported from version `128398`, only for VoIP and WAN RTT monitors.

1. SNMP credentials with 'Read Only' permission should be properly configured and associated with the source device.
2. Monitors should be added in the source device via CLI, in the format given below, or its equivalent:

### WAN RTT Monitor

```bash
ip sla $operation_id
icmp-echo $target_ip source-ip $source_ip
request-data-size $data-size
tos $tos
owner $ownername
threshold $rtt_threshold_millis
timeout $timeout_millis
ip sla schedule $operation_id life forever start-time now ageout $ageout_in_seconds
```

### VOIP Monitor

```bash
ip sla $operation_id
udp-jitter $target_ip $target_port source-ip $source_ip source-port $source_port codec $codec_name advantage-factor $mos_value
tos $tos
owner $ownername
timeout $timeout_millis
ip sla schedule $operation_id life forever start-time now ageout $ageout_in_seconds
```

### Dynamic Parameter Details

```bash
$operation_id -> Unique Operation ID for IP SLA Monitor
$target_ip -> Target/Destination IP Used
$source_ip -> Source IP Used
$data_size -> Request Data Size i.e. payload
$tos -> TOS Value
$ownername -> Owner Name (Optional)
$rtt_threshold_millis -> Time in Millis to Check Overthreshold
$ageout_in_seconds -> Age out Value.
$target_port -> Target Port used in VoIP Monitor
$source_port -> Source Port used in VoIP Monitor
$codec_name -> Codec Type supported in VoIP Monitor
$mos_value -> MOS Value
```

In OpManager, pushing IP SLA configurations to devices requires SNMP write permissions. However, starting from version 12.8.398, users can now discover and add existing IP SLA monitors from the source device using only SNMP read-only permissions, eliminating the need to push configurations manually.

## To enable IP SLA Responder

To monitor the destination Cisco device, please enable the SLA responder. For detailed instructions on how to enable the SLA responder on Cisco devices, refer to the following documents.

- [Configure Cisco IP SLAs - Switches](https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst2960/software/release/15-2_3_e/consolidated_guide/b_1523e_2960p_2960c_cg/b_1522e_2960_2960c_2960s_2960sf_2960p_cg_chapter_011110.pdf)
- [Configuring IP SLAs - UDP](https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipsla/configuration/15-mt/sla-15-mt-book/sla_udp_echo.html#GUID-61419D87-55C1-4666-957B-816F89C25EAF)

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