IP SLA Monitoring and Network Service Assurance Management

IP SLA is a diagnostic tool designed by Cisco IOS to help users analyze network performance. It works by actively and continuously collecting data from components within the network—data such as device connectivity rates, communication latency, packet loss, server or site downtime, and other information giving administrators insight into the health of their IT infrastructure.

Though this process varies depending on the types of operations being supervised, IP SLA monitoring generally works with the help of an IP SLA router and an IP SLA Responder. The router generates network traffic, and the Responder gathers information and facilitates the reporting process. The IP SLA router sends the originating timestamp (which states when the data packet was sent) to the Responder. Once this is received, the Responder inputs a receive timestamp (which states when the Responder received the packet) and a transmit timestamp (which tells users when the data packet was sent to its final destination).

From this process, an IP SLA monitor can gauge how well and how quickly devices can communicate with each other across the network. For example, if the data packet takes a long time to transfer between the router and Responder, it tells you there’s a latency or operational issue.

IP SLA monitoring and network service assurance management are practically the same. Both terms encompass the internal policies, algorithms, and methods used to gauge device performance and network health. The main difference lies in what devices are being monitored and managed.

Cisco developed IP SLA to analyze traffic data in real time, so many of its features and capabilities are only compatible with Cisco and network management system (NMS) devices and their peripheral endpoints. Network service assurance management is an updated version of IP SLA and extends its diagnostic tools to Juniper RPM and a few other external vendor devices. This helps eliminate technology silos capable of leaving blind spots across a network and making it harder for administrators to locate untraceable problem areas.

Though IP SLA operations are beneficial for data analytics and troubleshooting, they can cause more harm to your network if polling frequencies, testing schedules, and other monitoring features are deployed too often or consistently overlap.

Configuration issues have become more common as today’s standard offices and residences have embraced smart technology and interconnected mesh networks. The more devices and operations you integrate into your IP SLA monitoring software, the more data packets will be sent to and from your devices, meaning your network will have to work to ensure all components are running smoothly despite the increase in traffic.

This also means your monitoring system will become less effective. The more data and devices you try to keep track of, the harder it will be to stay on top of all recorded logs and historical results. To ensure you use IP SLA operations correctly, make sure to do the following:

• Keep tests local: Larger networks may house multiple servers, so avoid using
  tools designed for LAN services on WAN environments. For example, focusing on IP addresses local to each server
  makes them easier to keep track of. Otherwise, filtering through thousands of devices could cause you to
  misunderstand which servers they’re associated with.
  
• Test paths with supported traffic: Ensure each feature is in the appropriate
  context. For instance, UDP jitter is a test suited for sites designed to support video conferencing. Testing UDP
  jitter for non-video sites just makes your system work harder with no informational return.
  
• Decrease testing frequency: There’s no need to schedule testing intervals
  under 300 seconds long. Regular polling is key, but excessive polling becomes a burden.
  
• Watch for overlapping tests: If you conduct a ping test to an HTTP server and
  a TCP connection from a local switch to an HTTP server, you have a dilemma. Make sure your tests won’t collide
  and cause communication overload before you schedule them.
  

SolarWinds VNQM is the ultimate IP SLA monitor, providing granular and scalable insight into your network’s performance metrics. You can add IP SLA operations already existing on your devices to VNQM or create your own network service assurance operations to conduct.

The network service assurance operations VNQM supports include the following:

• Domain Name Server (DNS) Operation: Calculates the time it takes to receive
  after a DNS request is sent to check if DNS servers are functioning properly.
  
• File Transfer Protocol (FTP) Operation: Like DNS operations, FTP operations
  measure the time needed for a device and FTP server to obtain a file to ensure FTP servers work successfully.
  
• HTTP Operation: Measures web service response times to help you gauge the
  health of HTTP servers.
  
• Dynamic Host Configuration Protocol (DHCP) Operation: Computes the time it
  takes to find a DHCP server and retrieve a leased IP address from it to monitor communication processes
  involving DHCP servers.
  
• TCP Operation: Focuses on WAN quality by testing how long it takes for two
  devices to connect at a specific port.
  
• UDP Jitter Operation: Similar to TCP testing, except it uses a specific port
  number as opposed to a general port and traces the route and timestamps of data packets sent and received
  between devices.
  
• VoIP UDP Jitter Operation: Ensures call path data is healthy and latency-free
  across your VoIP network by simulating traffic and measuring data packet delays.
  
• Internet Control Message Protocol (ICMP) Echo Operation: Calculates the total
  time it takes for Cisco and IP-driven devices to communicate on your network using ICMP echo requests. This test
  helps narrow down the devices not working as they should.
  
• UDP Echo Operation: Mimics the ICMP Echo test, except it uses UDP Echo
  requests instead of ICMP Echo requests to find a general problem area within your network.
  
• ICMP Path Echo Operation: Uses sets of data chunks to measure round-trip time
  between nodes on a specific route. This is another way of checking device health.
  
• ICMP Path Jitter Operation: Also measures node health with a hop-by-hop
  approach for VoIP networks.
  

Setting up VNQM isn’t a difficult process. You just have to ensure you account for all devices, routers, and servers.

To start, install SolarWinds VNQM using the SolarWinds Platform
installer guide for a detailed list of system requirements and instructions. After installing VNQM, discover and add your Juniper RPM, Cisco, and Network service assurance-compatible devices.

You’ll then need to add your Cisco router to VNQM and enable access via SNMP read/write, SSH, or CLI through Telnet. This allows VNQM to deploy network service assurance operations. After your Cisco router is connected, configure VNQM to conduct the operations you want to get the data you wish to monitor. For detailed steps, you can use the “Add network service assurance operations to SolarWinds VNQM” instruction page.

Once you complete your operations checklist, you can view incoming data on the SolarWinds Platform Web Console dashboard. From here, you can spot and troubleshoot flagged problem areas and set up alerts to automatically notify you of issues requiring immediate attention.

Don’t forget to include VoIP operation capabilities. Add Avaya or Cisco call managers to VNQM so the program can authenticate service accounts and facilitate communication and testing using call data packets. For VNQM to receive data from your call managers, ensure you’ve configured these devices to send data to VNQM. Soon after, VNQM will start gathering and analyzing data to help you conceptualize how well your VoIP services are running.

If you need further assistance installing, configuring, and navigating this IP SLA monitor, please see our step-by-step guide here.