Intermittent Sync describes a connection that, in a given period of time, repeatedly fails to physically negotiate or keep a connection. Intermittent Sync issues are some of the most persistent, prevalent, and difficult issues one can troubleshoot, due to the extensive and varied points of failure in networking. Addressing intermittent sync can seem like a daunting task, even for those well versed in troubleshooting.

The best way of identifying, and correcting issues such as these, is to reduce the variables to their most basic states. This ensures we're introducing as few variables as possible to the setup, and likewise, as few points of failure as possible. When we're working with a simplified network, we don't need to make assumptions regarding your setup, or how the data is manipulated from end to end.

Common Points of Failure

 

Physical Line Issues

Physical Line issues can be described as physical problems that may exist between our equipment and yours. This includes the telephone network (the infrastructure providing your service), the internal wiring of your home, or even the telephone jack serving your modem.

Examples of Physical Line Issues

• Loose connections between your modem and the wall
• Damaged telephone lines (water damage, corrosion, breaks, grounds, and shorts in the copper)
• Extraneous wiring connected to the internal wiring of your home
• Bad network cables (including RJ-45 Ethernet Cables and RJ-11 Telephone Cables)

Device Failure

Many electronic devices can fail in erratic and spectacular ways. Other times, they just start behaving strangely. Repeatedly needing to restart a modem, or router, to establish or re-establish your connection is a frequent indicator of device failure.

Examples of Device Failure

• Modems or networking components that have developed physical issues such as bad capacitors.

General Troubleshooting

Identifying Intermittent Sync

Intermittent Sync only pertains to connections that physically lose connection. It's easy to get Intermittent Sync confused with many other types of issues.

When your modem first starts, it will attempt to synchronize with the equipment that sends the DSL signal over the telephone lines, measuring the noise and voltage to meet a compromise of stability and speed. The equipment and the modem will agree on a set speed based on the environment at that point in time, entering a phase of connection called a "handshake".

If at any point in time the voltage or noise changes significantly, the modem and the equipment sending the DSL signal necessarily renegotiate the settings of the connection. When this happens frequently, it is defined as Intermittent Sync.

• Intermittent Sync is not slow speeds caused by Bandwidth Saturation.
• Intermittent Sync is not Wireless Interference.
• Intermittent Sync is not when one website works, and others don't. You can use services such as http://www.isup.me/ to determine if a website is having issues.
• Intermittent Sync is not when one device works, and another doesn't. This most likely is an issue with the device experiencing issues, and troubleshooting resources are likely available here: Sonic Wiki

Intermittent Sync only occurs when the modem frequently needs to renegotiate a connection due to changing variables on the line.

There are certain symptoms, however, that make troubleshooting Intermittent Sync much easier to diagnose.

• Intermittent or total loss of dial tone
• Static, fuzz, clicking, echoes, or other noise on the telephone line
• Dropped calls

If you encounter these issues, please give our customer support a call at your earliest convenience. These are indicative of a physical line issue, and must be addressed before stability can be restored. Only you can prevent prolonged intermittent sync issues.

Simplifying your network

 

Once you have determined a likely culprit, you’ll want to simplify your network to ensure you’ve identified the source issue. Most of the time, this means connecting your computer directly to your Sonic provided modem with Ethernet. This gives you the best possible chance to remove erroneous variables that might otherwise interfere with the troubleshooting process.

Optimal Network Setup for Troubleshooting

Connect your computer directly to the DSL modem via Ethernet, bypassing firewalls, secondary routers or extenders, cellular hot-spots, or anything else that operates on your network (aside from a single computer). Connect the modem directly to a telephone jack, bypassing any filters, splitters, or other telephone equipment.

With this simplified setup, see if you can get online by opening a web browser.

If you’re able to surf, it means that some variable in your previous setup may have been contributing to your connection issue. Try and utilize this simplified setup for as long as possible to determine whether or not the issue has been addressed; if the connection is maintained long enough to be reasonably sure the issue has been resolved (typically multiple hours, 24 hours if possible), begin re-adding your networking equipment, one device at a time.

Minimum Point of Entry

If you're still experiencing Intermittent Sync, the best way of delineating this issue is by continuing to reduce the variables between your internal network, and the external network. The next best step is to connect your modem directly to the Minimum Point of Entry, also known as the Demarcation Point, the Phone Box, "AT&T Box", or MPoE.

This is the point at which the telephone lines enter your premises. By connecting the modem here, we can determine if intermittent sync persists. If so, we can reasonably determine that the issue exists external to your home.

If not, we can be reasonably sure that the issue stems from within the premises. This distinction is important - if we dispatch the wrong technician to address a problem, this might significantly delay resolution. Technician appointments to address issues on the inside of a premises will be unable to enact repairs on the external telephone network.

Networking Tools

If you’re still experiencing an intermittent connection, you can make use of several tools to further aid in the troubleshooting process. These vary slightly depending on your operating system, but all current operating systems should have basic, low level tools, that can test for basic connectivity and will provide meaningful information in diagnosing intermittent sync issues.

While these tools will not fix the problems you may be experiencing, it will assist in identifying where the issues are occurring, and at what point in time the issues present themselves. With intermittent sync issues, all information is good information!

Ping

 

The most basic tool at your disposal is the ping tool, available on Windows, OSX, and Linux terminals. A ping is a tool that measures the time it takes, and the success rate, of communicating to a networked device. To initiate a ping, open your terminal, and simply input ping followed by an address, eg: ping 209.204.190.64

You will be presented with a number of successes or failures; if things are operating normally, you should see 100% response. You can also use ping -t 209.204.190.64 to continuously ping an IP address. This will potentially provide you with more information, and give you a better, fuller picture, of how frequently (or infrequently) your computer is able to communicate on the network.

• Ping indicates your latency in milliseconds. If this is inordinately high (above 100ms), it might be indicative of activity on your network, such as an ongoing upload or download. In these cases, high latency is expected.
• You can ping your Sonic equipment to determine if an issue exists between your computer and that device. Pinging 192.168.42.1 should result in a very quick response (under 10ms), even if your WAN connection is under load.

Continuous Ping Script

If you're interested in running a continuous ping on Windows, you can save the output (including timestamp) to a text file by using the following command:

ping -t 209.204.190.64|cmd /q /v /c "(pause&pause)>nul & for /l %a in () do (set /p "data=" && echo(!date! !time! !data!)&ping -n 30 209.204.190.64>nul" >C:\ping.txt

This script will create a text log that can be used to determine when these issues arise, and are helpful in diagnosing the underlying problems. You can use this on your own to troubleshoot issues, or to supplement the troubleshooting process with our customer support.

Traceroute

 

Another tool that’s at your disposal is traceroute - tracert on Windows computers, and traceroute on Linux or OSX. A traceroute illustrates the path taken by the packet your computer sends to reach the destination address you specified, essentially tracing the route from point A to point B.

This can be useful in determining where an issue might exist between our WAN network, and your LAN network. A traceroute is extremely helpful if you’re able to get to some websites, but not others, as it displays where along the way the packet transmission fails.

Traceroute depicts data travelling to your specified destination by breaking down the path it takes into hops. Each hop is an intermediary point between your computer and the destination, very similar to how Google Maps or Mapquest would break down directions.

Making sense of a Traceroute

When interpreting the results of a Traceroute, keep in mind that latency is cumulative. Just because you see high latency for hop #5 doesn't mean this is indicative of a problem, especially if subsequent hops show normal latency, as depicted to the left.

Likewise, if you see packet loss on a specific hop, and not on the subsequent hops, it means that this hop, or the equipment serving that hop, has likely been configured in such a way that it transmits data as quickly as possible, but may not respond to every packet. More information about Traceroute can be found here.