Packet loss on an Internet connection can be disruptive to voice and data traffic. It can noticeably slow Internet throughput speeds and disrupt realtime applications like Virtual Private Networks (VPNs). Lost packets may cause voice and video to be delayed, choppy or garbled. It may also disconnect Voice over Internet Protocol (VoIP) calls.
The IP Packet Loss and Delay Test tool provides a means to inspect an Internet connection for packet loss. It analyzes the route from the Test Center to any pingable public IP address. It will find the location of any trouble whether it is the end user’s connection or congestion within the ISP’s network. It will automatically detect any change of routes within the ISP and track statistics separately.
Finding the Source of Packet Loss
The IP Address that was monitored is referred as the Destination IP. A quality Internet connection should have 0.1% lost packets or less. If the packet loss is 0.1% or less at the Destination IP address, then packet loss at any of the other hops can be ignored.
If packet loss is greater than 0.1% at the Destination IP address, examine the hops immediately ahead. Do they exhibit similar loss percentages? If they do, then the first hop where lost packets start occurring could be the cause.
Examine the timeline graph at the bottom of the Route Pattern (RP) report page. If the lost packets are grouped together during times of the day, narrow the report period at the bottom of the page just before the beginning and just after the end of one of the groups of losses. Does the loss of the suspect hop still exhibit similar loss percentage? If so, click on the hyperlink of the address to compare the two hops more closely. Do the losses over time still seem similar? If not, consider examining another hop as the cause of the packet loss.
Source of Packet Loss at Destination IP Only
If packet loss is occurring greater than 0.1% at the Destination IP and not the hops immediately preceding, then the source of trouble is between the last hop with insignificant packet loss and the Destination IP or in the device responding to pings for the Destination IP.
Some factors that can cause packet loss at the Destination IP include:
1. Equipment problems with the cable/DSL modem or router including potentially over-heating equipment.
2. Undetectable bridge/switch or other networking hardware (i.e. hub) in front of the Destination IP device.
3. Congested Internet connection. In other words, too much traffic for the delivered speed. Please note that delivered speed may be different then the expected or promised speed.
4. Wiring outside or inside the building but before the device which responds to pings for the Destination IP. Quality of wiring is poor or deteriorated from weather, age, animals and other environmental factors.
5. Environmental interference from microwaves, wireless radios, refrigerators, etc too close to the wiring or cable/DSL modem or router.
If the Internet connection is a DSL circuit:
1. Other circuits, such as commonly used T1s, in the Local Exchange Carrier’s (LECs) cable bundle could be interfering with the DSL circuit’s frequency.
2. The DSL splitter, which divides the phone line from the DSL circuit, could be faulty.
3. The LEC could have load coils or bridge taps on the cable which is delivering the DSL circuit.
4. Other analog devices like fax machines or cordless phones have been attached to the phone line before the DSL splitter splits off the DSL circuit.
If the Internet connection is supplied by cable modem:
1. The coax cable passes through more than one splitter before the cable modem.
2. Cable modem attached to wrong port of the splitter.
3. The decibel level of the cable TV transmission is too low. The cable repairman will frequently check this first. Be advised that the decibel level can change throughout the day.
Run the Report Again
Once a potential cause of trouble has been eliminated, run the report again. Is there a difference? If not, look for another potential source of trouble. And do not forget, many times there can be multiple sources inducing problems on an Internet connection.