Ping the WAN link through ICMP

How the ICMP ping test works

Ping is a dedicated IP network tool that Ping sends an ICMP echo request message to the destination and reports whether it receives the expected ICMP echo response. Each operating system has the Ping tool installed, and any common enterprise platform, like Windows or Mac OS X, can find it.

You can run the Ping delay test on any network device. The target host can be any other device, such as a computer, a router, or any device with an IP address on the network. In any case, our goal is to measure the time it takes to ping data to the WAN, and the closer the target host is, the better the WAN link will be.

Most of this generation of WAN routers and LAN switches attached to their wiring cabinets have ping, so many times you can initiate ping requests from the WAN router's control port or from other network devices in the wiring cabinet, targeting other switches or routers on the other end of the WAN.

Ideally from a wiring cabinet, such as your headquarters to ping to the branch office wiring cabinet of the target device (and vice versa), but this is usually not possible. Because in most cases, the enterprise security policy restricts physical or logical access to the WAN router or switch control port. Because an error command at the switch or router control port can disable the device, most businesses restrict access to the device's control port.

Similarly, many businesses prohibit their network facilities from automatically responding to ping because such a response could cause a denial-of-service attack to occur on a switch or router. So you can easily tell that the source and target devices that generate the measurements are computers, because they can run IP on the other end of the WAN and answer the ping.

In fact, all networks today have network address translation (NAT) deployed, and the device you choose to target must have a public IP address or map to your firewall so that your ping request is accepted.

Fortunately, LAN latency is generally low, probably within 1 to 2ms, so if you need to ping LAN to LAN on a WAN, you will find that 2 to 4ms of your measurements are related to two local LANs, and you need to deduct this value.

Collect Ping Delay report

Now that you know the Web tool, you can collect ping delay measurement reports. The only task for Ping is to generate the Echo command on the network, and you will find that the Ping tool has many options, most of which we can do without. Ping in Windows 7 has 16 different options.

The easiest way to run a ping is to open a command prompt at Windows or run Mac OS X's Terminal program. If you hate using a command prompt, there are a number of free front-end graphical user interfaces (GUIs) for pinging. Constantly trying to ping the various parameters, this will not be a problem, as long as you do not have to ping non-stop to send a large number of packets.

After the ping, enter the network name of the target device or the public IP address of the destination router, switch, network workstation, and other IP devices.

Under Windows, enter ping <target IP address or Target IP Host name>

Knock the carriage return and it will try to ping the destination IP device. Windows typically produces 4 echo requests and then summarizes the reports. and Mac OS X continues to do so by default. Writing the-C 4 option, OS X's ping will execute 4 times as Windows.

Under Windows, enter: Ping–c 4 <target IP address or Target IP Host name>

Then hit enter. It will attempt to ping the target IP device. After displaying the detailed results, you will receive a report of your concern.

Understanding Ping Delay Test Report

First of all, look for the word "loss" in packet loss, which is best to always be 0, if not, either your network is experiencing a temporary pressure, or the configuration is incorrect. If "loss" is Non-zero, it is likely that the user starts complaining to you. Packet loss usually requires further monitoring and taking necessary action.

Because any packet loss is transient, ping can determine if the packet is still missing for the next time. If you still report packet loss in a few hours, you should pay attention. Contact your ISP and let them know the situation. At least they will tell you whether your link detects any technical problems. Also possible when your traffic load requires the upgrade bandwidth.

Our goal is to keep the network low, and Ping will tell us how long each echo takes over the network, that is, a roundtrip transmission. The statistical data in the report will tell us if the delay is stable. Logging the results of ping, even manually, can establish benchmarks for your own network. If you suspect a network problem, you will need these benchmarks as reference points.

Usually the ping response ranges from 10 to 20ms, or the second is 1/10 to 1/5. This is not enough to affect the user. This is not a good omen if you start to see a big float when you ping the answer. The change in latency is called jitter, which can cause problems with time-sensitive applications such as VoIP.

The temporary ups and downs of round-trip transmission time suggest that the network is more congested. For example, Ping displays 62ms across a WAN link to the Internet, but when a file crosses, it immediately increases to 250ms. When latency and jitter results are still unacceptable, WAN optimization and QoS solutions should be considered to control bandwidth or upgrade your WAN bandwidth.

This article is from "It Chen Yi" blog, please be sure to keep this source http://itchenyi.blog.51cto.com/4745638/1011136

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