A 10 Gigabit network traffic (re)player.

disk2n is able to replay network traffic previously captured with n2disk on live networks observing the original inter-packet time. disk2n supports the industry standard PCAP file format (with both regular and nanosecond timestamps).
disk2n has been designed to replay multiple pcap files of any size (even terabytes of traffic) with limited memory usage. You can specify a playlist of pcap files or a timeline produced by n2disk with a time interval, and instruct disk2n to continue from the first packet when the last one is reached. It is possible to determine in advance the amount of memory used by disk2n: it uses a memory buffer of arbitrary size to cache the next packets to replay, achieving great transmit performances with limited memory usage.

disk2n can be effectively used to perform numerous activities, among these:

  • Reproduce selected long-term network activities.
  • Replay previously captured traffic to a different network interface.
  • Generate traffic to test network equipments that no traffic generator can do being them usually limited in replay duration.

Main disk2n Features

The current disk2n version is much more than a simple packet replay application, like pfcount. Some of the disk2n features include:

    • Fully user configurable.
    • Use of the standard PCAP file format (regular and nanoseconds).
    • Line-rate packet replay.
    • Packet reforging. disk2n is able to reforge source/destination MAC/IP/Port on the fly, recomputing destination MAC in case of multicast and recalculating checksum.
    • Inter-packet time tuning. disk2n is able to replay traffic at capture rate or at a user-defined rate.
    • Multi-core support. disk2n has been designed with multicore architectures in mind. It uses 3 threads (one for reading packets from disk, one for packet transmission and one for precise time generation). The communication between threads has been carefully optimized.
    • PF_RING acceleration. disk2n exploit the packet transmission acceleration offered by PF_RING ZC.
    • Direct-IO disk access. disk2n uses the Direct IO access to the disks in order to obtain maximum disk-read throughput.


disk2n has been designed to keep up with multi-Gigabit speeds on commodity hardware.

Packet Size (Bytes) disk2n Sustained Throughtput
disk2n with PF_RING ZC
fixed 64 Wire rate
fixed 128
fixed 512
random 64-1500

The table above shows the result of a worst-case performance test using the following system configuration.

  • OS: Ubuntu 12.04
  • CPU: Intel(R) Xeon(R) E5-2643 @ 3.50GHz
  • Motherboard: Supermicro X9DRW
  • Memory: 16 GB
  • Card: Intel PCIe 82599 10 Gigabit
  • Disks: 12x 1TB 10K RPM SATA
  • Command used:
    • disk2n -i zc:eth1 -A /storage/timeline -c 1 -w 2 -S 3 -g -b 2048 -C 4096 -B “2014-03-11 16:14:50” -E “2014-03-11 16:18:00”

User’s Guide

For all the disk2n configuration options and performance optimisation techniques, please refer to the  n2disk User’s Guide.

Operating Systems



disk2n is distributed under the EULA and requires a license per system.

Get It

You can test disk2n as binary package (it is part the n2disk package) or get a permanent license.

Max Replay Speed Linux Unix / OSX / Win32
10 Gigabit Enhanced PF_RING support (i.e. full packet transmission acceleration) Basic libpcap-based packet transmission (Available on Request)


  • Test reports have been measured on Linux in the worst-case conditions (64 byte packets)
  • Replay speed depends on your disk setup and server being used.
  • You can use disk2n as software application or embedded on the nBox recorder.
  • Research and no-profict can have disk2n at no cost. Please contact us for details.