Basic Networking Troubleshooting Understanding

PING –  Packet Internet Groper

PING is primary tool used to troubleshooting network connectivity and verify reachability between computer system over the network or internet.It’s universal networking utility and a network testing tool almost presented in every operating system worldwide. Everyone in computer world well known this ping pong and even very common slang speaking in our young generation “Ping me” cool expression.

Basically ping is command line (CLI based) tool and as I said it is available in every operating system.it is very common tool to validate the connectivity between two computer system, networks and connectivity testing to internet like easy to ping techmusa.com and ping 4.2.2.2 to test internet connectivity from your system.

Ping is TCP/IP protocol family utility/tool and it’s designed to correspond only those system who are using TCP/IP protocol for communication.

The ping command operates by sending Internet Control Message Protocol (ICMP) Echo Request messages to the destination computer and waiting for a response.

¶ Ping consist multiple components which help to measure network connectivity health and performance. Let brief them below-:

1. ICMP
2. TTL
3. Network latency
4. Jitter
5. RTT – Round-trip time
6. Packet lose

ICMP – Internet Control Message Protocol

ICMP is basically a TCP/IP family protocol and typically work on IP layer in the OSI model. Network utility ping and trace route use ICMP (Internet Control Message Protocol) Echo function (Echo Reply, Echo Request and Destination Unreachable) use to discover and diagnostic the network error.

TTL – Time To Live

Every IP packet travel over the internet having TTL value set inside the IP packet. TTL value indicate the life of packet that traveling over the internet.

The TTL header is 8 Bit (octet) and maximum value of TTL is 255.This value refer the amount of time or “hops” that an IP packet is permitted to travel before being discarded by a router.

The ping and the traceroute utilities both make use of the TTL intentionally sends packets with low TTL values so that they will be discarded by each successive router in the destination path.

Network Latency

Network Latency test check by simply running the ping command at your terminal or Command Prompt. At bottom you can see the Minimum , Maximum and Average Latency.

Microsoft Windows [Version 6.1.7601]
Copyright (c) 2009 Microsoft Corporation. All rights reserved.

C:\Users\t973824>ping techmusa.com

Pinging techmusa.com [94.23.164.129] with 32 bytes of data:
Reply from 94.23.164.129: bytes=32 time=117ms TTL=50
Reply from 94.23.164.129: bytes=32 time=115ms TTL=50
Reply from 94.23.164.129: bytes=32 time=116ms TTL=50
Reply from 94.23.164.129: bytes=32 time=118ms TTL=50

Ping statistics for 94.23.164.129:
 Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 115ms, Maximum = 118ms, Average = 116ms

C:\Users\t973824>

Network Latency is typically refer to time that one TCP/IP Packet takes time to reach from source to destination node. TCP/IP packet takes certain amount of time to travel from one device to another and time is referred to as latency considers in ms (milliseconds)

Network tools such as ping and traceroute tests provide network latency by determining the time that takes a node to reach other node over the network. Ping and trace route records network latency typically measured in milliseconds (ms). 

 Statistically, Network latency is very important factor that put impact on network performance. A high latency (high number packet delay) in network connection will be a bad signal that impact network performance and upload an download speed, whereas a low latency connection can benefit from minimal delay times.

Minimums Standard value for Latency-:

High latency put bad experience and significantly noticeable in real time application such as streaming application voice and video application likewise skype, voice calling, zoom etc.

Network latency can occur through various reason and following as below-:

• Routing design – Inappropriate network routing can one cause of increasing network latency. Long haul network path adding extra hops and dynamically change path over the internet is very common cause of higher latency.  
• Network loop – Network loop is another cause of high latency since packet back and forth stuck in loop.
• Network Distance – Geographical distance could be another cause of high network latency .Long distance mean long time to travel across one continental to another continental across countries via sea or satellite.
• Physical connection/connectivity – Depend how you connecting is through fiber cable or satellite. Defiantly satellite link adding more delay and increase network latency.
• Low Bandwidth – Low bandwidth and higher utilization can be one cause of higher latency.

Network Jitter

Jitter is unexpected spike in normal packet flow in network that add more delay in packet delivery and can see irrational behaviors of packet flow. Technically jitter is packet delay variance that calculated the time difference between packet flow. It’s create disorder in the normal sequence of sending data packets.

High jitter of 30ms and above can cause disruption as the normal sequence of sending data packets is confused and rearranged.

Jitter break the constant flow of packet delay and can put the negative impact on time sensitive application such as voice, video and gaming will not give you a pleasant experience.

For example – In a VoIP call, some packets may arrive faster and some may arrive slower than they should. As a result, users will suffer from audio issues including delays that lead to them talking over each other.

RTT – Round-Trip Time

Round-trip time (RTT) referring the time length in milliseconds (ms) that a TCP/IP packet takes to sending information from a source to destination node and  acknowledge back to the originator.

Ping utility help to measure the Round-trip time of packet and help network administrators to diagnose the speed and reliability of network connections.

For example – when you send couple of ping to destination server or node available on the network. Ping shows the statistics of Round-trip time (RTT) in the bottom as result.

Packet Loss

Packet loss is really nightmare salutation handling for any network engineer. It is very common issue in network and every engineer encounter this type of challenge. Packet lose degrade the network performance and badly hit to network performance and cause of leading network slowness.

Packet loss occurs when one or more packets of data travelling across a computer network fail to reach their destination. Packet loss is either caused by errors in data transmission, typically across wireless networks or network congestion. Packet loss is measured as a percentage of packets lost with respect to packets sent.

Typically ping and traceroute utility can help to measuring the percentages of packet lose in a network.

Packet Loss Monitoring is an important part of network monitoring, especially if you are using streaming technologies, which are very sensitive to lost or reordered packets.