how to check udp packet loss on pcap wireshark

How to Check UDP Packet Loss on PCAP and Wireshark

As an administrator of a real-time online game server, you are well aware that packet loss can have a significant impact on the user experience. When packets are lost or dropped during transmission, it can lead to lag, disconnections, and other issues that affect your clients. In this article, we will discuss how to check UDP packet loss on PCAP and Wireshark.

To start, let's take a closer look at the ifconfig command output:

ifconfig ens192

ens192 Link encap:Ethernet HWaddr 00:50:56:03:25:14

This output shows that the network interface card (NIC) is set to use Ethernet encapsulation and has a hardware address of 00:50:56:03:25:14. However, this information does not provide any insight into packet loss.

To capture and analyze network traffic, we can use Wireshark, a popular network protocol analyzer. Wireshark allows us to capture packets and display them in a human-readable format, making it easier to identify issues such as packet loss.

Capturing Packets with Wireshark

To capture packets using Wireshark, follow these steps:

1. Open Wireshark on your system.

2. Select the network interface you want to capture from (in this case, ens192).

3. Click the 'Start' button to begin capturing packets.

4. Once you have captured a sufficient amount of traffic, stop the capture and save it as a PCAP file.

Analyzing Captured Packets with Wireshark

To analyze the captured packets in Wireshark, follow these steps:

1. Open the PCAP file in Wireshark.

2. Use the 'Filter' menu to select the protocol you want to focus on (in this case, UDP).

3. Look for packets that have a 'Flags' value of 'Dropped' or 'Lost'. These packets were either dropped by the network interface card or lost during transmission.

Checking Packet Loss on PCAP

To check packet loss on PCAP, follow these steps:

1. Open the PCAP file in Wireshark.

2. Use the 'Statistics' menu to select 'Protocol Hierarchy'.

3. Look for the UDP protocol and click on it to display a list of packets.

4. Use the 'Filter' menu to select the packet loss filter (e.g., 'udp.flags == 0x04').

5. This will show you a list of packets that were dropped or lost during transmission.

Configuring Buffer Ring, Max Windows Size, and Other Settings

To optimize network performance and reduce packet loss, it's essential to configure your network interface card settings properly. Here are some steps to follow:

1. Edit the /etc/network/interfaces file on your Ubuntu system.

2. Add the following lines to the end of the file:

```

buffer ring 4096

max windows size 65535

```

3. Restart the network service by running the command 'sudo service networking restart'.

RX bytes:44109471 (44.1 MB) TX bytes:19484534 (19.4 MB)

In this example, the RX bytes indicate that 44.1 MB of data has been received, and the TX bytes indicate that 19.4 MB of data has been transmitted. However, you can see that some packets were dropped during transmission.

TX packets:76478 errors:0 dropped:0 overruns:0 carrier:0

RX packets:574749 errors:0 dropped:83 overruns:0 frame:0

This output shows the number of packets sent and received, as well as any errors or drops. You can see that 83 packets were dropped during reception.

UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1

In this example, the network interface is set to use a maximum transmission unit (MTU) of 1500 bytes and has a metric value of 1.

Packet loss can have a significant impact on real-time online games, causing lag, disconnections, and other issues. By following the steps outlined in this article, you can check UDP packet loss on PCAP and Wireshark, optimize your network interface card settings, and improve overall networking performance. Remember to regularly monitor your network traffic and adjust your settings as needed to ensure optimal performance for your online game server.

How to check udp packet loss on pcap wireshark