Limitations

Napatech Link-Capture™ Software and WinPcap-NT Installation Guide for Windows

Platform
Napatech SmartNIC
Content Type
Software Installation Guide
Capture Software Version
Link™ Capture Software 12.9

Filtering

While WinPcap-NT allow you to run WinPcap applications with Napatech SmartNICs, you should be aware of a few limitations to fully take advantage of Napatech SmartNICs:

  • Filtering in WinPcap (using pcap_setfilter()) is SW-based and does not utilize the filtering capabilities of Napatech SmartNICs. Filtering configured using ntpcap.ini is HW-based. You can also configure HW-based filtering using the ntpl tool.
  • Napatech SmartNIC drivers do not provide file descriptors. Therefore it is not possible to get a valid OS file descriptor through pcap_fileno(), which returns -1. pcap_get_selectable_fd() also returns -1.
  • pcap_set_promisc() has no effect on a Napatech WinPcap device, since this is always in promiscuous mode.

Unsupported functions

  • Napatech SmartNIC drivers do not provide file descriptors. Therefore it is not possible to get a valid OS file descriptor through pcap_fileno(), which returns -1. pcap_get_selectable_fd() also returns -1.
  • pcap_set_promisc() has no effect on a Napatech WinPcap device, since this is always in promiscuous mode.

Only one version of WinPcap

  • Multiple versions of WinPcap cannot be installed on a Windows system. Before installation of WinPcap-NT, any existing WinPcap installation must be uninstalled. This can be done automatically by the WinPcap-NT Installer, or by using the uninstaller provided by the existing WinPcap installation.

Style Conventions

Bold typeface is used for names of, for instance, user interface elements and software components.

Italic typeface is used for replaceable text.

Monospaced typeface is used for code, commands and file names.

Abbreviations

API

Application Programming Interface

BP

ByPass

CRC

Cyclic Redundancy Check

dll, DLL

Dynamic-Link Library

DN

Document Number

HB

Host Buffer

hba

Host Buffer Allowance

http

HyperText Transfer Protocol

HW

HardWare

Id, ID

IDentifier

IFG

Inter-Frame Gap

MB

MByte

NEBS

Network Equipment-Building System

NPF

Netgroup Packet Filter

nt, NT

NapaTech

NTAPI

NapaTech Application Programming Interface

NTPL

NapaTech Programming Language

NTUTIL

NapaTech UTIlity Library

NUMA

Non-Uniform Memory Access

pcap, PCAP

Packet CAPture

PTP

Precision Time Protocol

Rev.

REVision

Rx, RX

Receive

SCC

Self-Contained Cooling

STD

STanDard

SW

SoftWare

tx, Tx, TX

Transmission/Transmit

winpcap, WinPcap

Windows Packet CAPture library

References