8. Napatech Support¶
PF_RING has native support for Napatech adapters, the Napatech library needs to be installed under /opt/napatech3 in order to enable the Napatech module at runtime.
Napatech drivers and SDK installed. Latest Napatech SDK is available for download at https://www.napatech.com/downloads/.
Note: as of PF_RING 6.6 dynamic linking is used and you are able to use any ntanl driver version.
After installing the Napatech SDK, please make sure the driver is loaded with:
In order to get up and running with Napatech when installing from source code, run the following commands:
cd PF_RING/kernel && make && sudo insmod pf_ring.ko cd ../userland/lib && ./configure && make cd ../libpcap && ./configure && make cd ../examples && make sudo ./pfcount -i nt:0
Please note that:
- installing from repository, all applications are already compiled with Napatech support
- in order to open a port from the Napatech adapter you should specify nt:<PORT>, example:
pfcount -i nt:0
- in order to open a stream you should specify nt:stream<ID>, example:
pfcount -i nt:stream0
- streams with port aggregation or distribution (similar to RSS) can be created using the ntpl tool (ntpl -e “<command>”)
Note: it is possible to open the same stream from multiple applications at the same time (the slowest consumer will affect the others!). Instead it is not possible to open a port multiple times (as the port is reassigned to a new stream every time you open it).
Command example for ports (2 and 3) aggregation on a single stream (1):
/opt/napatech3/bin/ntpl -e "Delete = All" /opt/napatech3/bin/ntpl -e "Assign[streamid=1] = port == 2,3"
Command example for load balancing of all ports across 16 streams:
/opt/napatech3/bin/ntpl -e "Delete = All" /opt/napatech3/bin/ntpl -e "HashMode = Hash2TupleSorted" /opt/napatech3/bin/ntpl -e "Assign[StreamId=(0..15)] = All"
Command example for load balancing port 0 across 4 streams:
/opt/napatech3/bin/ntpl -e "Delete = All" /opt/napatech3/bin/ntpl -e "HashMode = Hash2TupleSorted" /opt/napatech3/bin/ntpl -e "Assign[StreamId=(0..3)] = port == 0"
Command example for merging two ports and load balancing them across 24 streams where the first 12 streams are bond on node 0 and the remaining 12 on numa node 1
/opt/napatech3/bin/ntpl -e "Delete=All" /opt/napatech3/bin/ntpl -e "HashMode = Hash5TupleSorted" /opt/napatech3/bin/ntpl -e "Setup[NUMANode=0]=Streamid==(0..11)" /opt/napatech3/bin/ntpl -e "Setup[NUMANode=1]=Streamid==(12..23)" /opt/napatech3/bin/ntpl -e "Assign[streamid=(0..23)]=port==0,1"
8.3. Adapter configuration for n2disk¶
In order to use the Napatech adapter with n2disk the configuration file /opt/napatech3/config/ntservice.ini should contain:
TimestampFormat = PCAP_NS PacketDescriptor = PCAP HostBufferSegmentSizeRx = 4
8.4. Napatech and Packet Copy¶
If you use the PF_RING (non-ZC) API packets are read in zero-copy. Instead if you use PF_RING ZC API, a per-packet copy takes place, which is required to move payload data from Napatech-memory to ZC memory. Keep this in mind!
8.5. Transmission Support¶
In order to use Napatech in transmission you need to make sure you have configured TX properly. Edit /opt/napatech3/config/ntservice.ini and make sure you have the following sections configured
[Adapter0] .. HostBuffersTx = [4,16,0] ..
8.6. Hardware Filtering¶
Napatech NICs support full-blown hardware filtering out of the box. Thanks to nBPF we convert BPF expressions to hardware filters. This feature is supported transparently, and thus all PF_RING/libpcap-over-PF_RING can benefit from it.
pfcount -i nt:3 -f "tcp and port 80 and src host 192.168.1.1"
As Napatech hardware filters are very advanced, filtering happens all in hardware.