Network Integration Guide › Troubleshooting › Some Files and Emails are Not Captured › Does the Network Traffic Contain Jumbo Frames?

Does the Network Traffic Contain Jumbo Frames?

Typically, jumbo frames are Ethernet frames with over 1518 bytes of payload. These packets are not normally allowed onto the Internet and cannot be analyzed by the NBA, but are sometimes seen on corporate networks.

To check whether the NBA is seeing very large packets (Linux Server platforms with Napatech card only)

1. Start a command shell either at the server’s keyboard or over SSH.
2. Enter the following commands:

   cd /opt/napatech3/bin’.
   ./monitoring’.
   Type ‘1’ to show the ‘ExtRMON’ screen.
   

3. Verify that these counters show zero:

   1519-2047 octets: 0x0000000000000000  2048-4095 octets: 0x0000000000000000
   4096-8191 octets: 0x0000000000000000  8192-Max octets : 0x0000000000000000
   

To check whether the NBA is seeing very large packets (Bivio 2000 platforms only)

1. Generate a diagnostics file.
2. From the resulting .gz file, extract stats.txt.
3. Open status.txt and check the jumbo frame ‘Tx, 1519-Max byte packets’ count.

The screenshot below shows an extract from status.txt on a Bivio 2000 appliance. The jumbo frame count shows that the NBA is not seeing very large packets:

Example status.txt on Bivio 2000 appliance: 1, Tx, 1519-Max byte packets.