# Latest **URL:** https://forum.p4.org/latest.md?page=2 [Latest](https://forum.p4.org/latest.md) · [Categories](https://forum.p4.org/categories.md) **Page:** 3 --- ## [How to setup IPv6](https://forum.p4.org/t/how-to-setup-ipv6/1338)
**Author:** [@dpilipczuk](https://forum.p4.org/u/dpilipczuk)\ **Replies:** 1\ **Last updated:** [June 20, 2025, 6:43pm UTC](https://forum.p4.org/t/how-to-setup-ipv6/1338 "2025-06-20T18:43:43Z")
Hi! I have college project regarding p4. I need to implement ipv4 ↔ ipv6 translation, but I have trouble with setting up the environment :confused: Ideally, I want to create topology with two hosts and one switch. One … --- ## [ModuleNotFoundError: No module named 'p4' when running make run in exercises/basic](https://forum.p4.org/t/modulenotfounderror-no-module-named-p4-when-running-make-run-in-exercises-basic/1331)
**Author:** [@kacperkuczynski26](https://forum.p4.org/u/kacperkuczynski26)\ **Replies:** 1\ **Last updated:** [June 6, 2025, 4:11pm UTC](https://forum.p4.org/t/modulenotfounderror-no-module-named-p4-when-running-make-run-in-exercises-basic/1331 "2025-06-06T16:11:20Z")
Hi all, I’m working on the basic exercise from the official p4lang/tutorials repo on a clean installation of Ubuntu 24.04 in VirtualBox. I followed the setup steps including: bash git clone https://github.com/p4lang/t… --- ## [Implementing P4 projects in real hardware](https://forum.p4.org/t/implementing-p4-projects-in-real-hardware/1072)
**Author:** [@absuarez](https://forum.p4.org/u/absuarez)\ **Replies:** 2\ **Last updated:** [June 6, 2025, 4:03pm UTC](https://forum.p4.org/t/implementing-p4-projects-in-real-hardware/1072 "2025-06-06T16:03:11Z")
Hello, I aim to implement the projects that I have been testing on Mininet and bmv2 switches on real hardware. However, I am not well-versed on which ones are the most adequate hardware to perform my tests. Can someon… --- ## [Help Needed: Connecting P4Runtime Controller to UfiSpace S9180-32X (Tofino)](https://forum.p4.org/t/help-needed-connecting-p4runtime-controller-to-ufispace-s9180-32x-tofino/1320)
**Author:** [@AL-OTU](https://forum.p4.org/u/AL-OTU)\ **Replies:** 1\ **Last updated:** [June 6, 2025, 2:33pm UTC](https://forum.p4.org/t/help-needed-connecting-p4runtime-controller-to-ufispace-s9180-32x-tofino/1320 "2025-06-06T14:33:04Z")
Hi everyone, I’m currently working with a UfiSpace S9180-32X switch (Tofino-based) and trying to get a Python-based controller.py working over P4Runtime gRPC to manage the switch pipeline. Current Setup: Switch: UfiSp… --- ## [Recompute IPv4 Payload Size in SRH: "We currently support only single stage actions."](https://forum.p4.org/t/recompute-ipv4-payload-size-in-srh-we-currently-support-only-single-stage-actions/1319)
**Author:** [@d.lake](https://forum.p4.org/u/d.lake)\ **Replies:** 4\ **Last updated:** [May 30, 2025, 9:27pm UTC](https://forum.p4.org/t/recompute-ipv4-payload-size-in-srh-we-currently-support-only-single-stage-actions/1319 "2025-05-30T21:27:09Z")
I’m trying to extract an IPv4 packet from an SRH6 packet and hitting a problem in the action: bit\<16\> srv6h\_size = (((bit\<16\>)hdr.srh.hdrExtLen + 1) \<\< 4) + 8; hdr.ipv4.total\_len = hdr.ipv6.payload\_len - srv6h\_s… --- ## [Help: p4types\_pb2 and google.rpc import errors in Python gRPC controller](https://forum.p4.org/t/help-p4types-pb2-and-google-rpc-import-errors-in-python-grpc-controller/1317)
**Author:** [@AL-OTU](https://forum.p4.org/u/AL-OTU)\ **Replies:** 0\ **Last updated:** [May 26, 2025, 5:42pm UTC](https://forum.p4.org/t/help-p4types-pb2-and-google-rpc-import-errors-in-python-grpc-controller/1317 "2025-05-26T17:42:10Z")
Hi everyone, I’m trying to get a Python-based P4Runtime controller working with a Tofino switch, but I’m running into a couple of import errors when using the generated protobuf files. I’ve already generated the binding… --- ## [Need Advice on P4 Tofino Setup – Platform Detection, Custom Controller, and IDS Project](https://forum.p4.org/t/need-advice-on-p4-tofino-setup-platform-detection-custom-controller-and-ids-project/1315)
**Author:** [@AL-OTU](https://forum.p4.org/u/AL-OTU)\ **Replies:** 1\ **Last updated:** [May 21, 2025, 5:13am UTC](https://forum.p4.org/t/need-advice-on-p4-tofino-setup-platform-detection-custom-controller-and-ids-project/1315 "2025-05-21T05:13:56Z")
Hey everyone, I’m working on a project using a Tofino-based switch (UfiSpace S9180-32X) and the Intel P4 SDE (version 9.13.1). I’m building a simple IDS (Intrusion Detection System) as part of a summer Project, and so f… --- ## [Enabling P4Runtime on psa\_switch](https://forum.p4.org/t/enabling-p4runtime-on-psa-switch/1311)
**Author:** [@lriccardip4](https://forum.p4.org/u/lriccardip4)\ **Replies:** 7\ **Last updated:** [May 19, 2025, 4:43pm UTC](https://forum.p4.org/t/enabling-p4runtime-on-psa-switch/1311 "2025-05-19T16:43:25Z")
Hello, and thanks again you all for your help. I’d like to ask how to enable a P4Runtime server on the psa\_switch, the one provided by the starting installer (install-p4dev-v8.sh), as it seems to me there is no way to e… --- ## [Control plane reads wrong values (INT)](https://forum.p4.org/t/control-plane-reads-wrong-values-int/1284)
**Author:** [@lriccardi](https://forum.p4.org/u/lriccardi)\ **Replies:** 18\ **Last updated:** [May 19, 2025, 7:57am UTC](https://forum.p4.org/t/control-plane-reads-wrong-values-int/1284 "2025-05-19T07:57:12Z")
Good morning, and before of all thank you for taking your time to read this. I am implementing a simple form of INT reporting from the dataplane to the control plane, using the BMv2 software switch. The current P4 progr… --- ## [Stateful metadata per-packet](https://forum.p4.org/t/stateful-metadata-per-packet/1307)
**Author:** [@mulmoo](https://forum.p4.org/u/mulmoo)\ **Replies:** 3\ **Last updated:** [May 9, 2025, 4:07pm UTC](https://forum.p4.org/t/stateful-metadata-per-packet/1307 "2025-05-09T16:07:37Z")
Hello. I’m creating a P4 program using P4\_16 in a BMv2 environment. The task I want to achieve is to modify packet metadata in S1 and then forward the packet to S2, where S2 would be able to read and use the metadata va… --- ## [Encountering difficulties during in band network telemetry(INT)](https://forum.p4.org/t/encountering-difficulties-during-in-band-network-telemetry-int/1302)
**Author:** [@16603379565](https://forum.p4.org/u/16603379565)\ **Replies:** 2\ **Last updated:** [April 29, 2025, 1:13am UTC](https://forum.p4.org/t/encountering-difficulties-during-in-band-network-telemetry-int/1302 "2025-04-29T01:13:57Z")
I have been trying to test INT recently. I am using ONOS2.2.5, Ubuntu 20.04, and the Linux kernel is 4.15.0-154. When I start bmv2 demo. py, ONOS encounters the following error. How can I solve it? --- ## [Grpc error after installing flow rules](https://forum.p4.org/t/grpc-error-after-installing-flow-rules/1300)
**Author:** [@JOHN](https://forum.p4.org/u/JOHN)\ **Replies:** 1\ **Last updated:** [April 26, 2025, 10:12pm UTC](https://forum.p4.org/t/grpc-error-after-installing-flow-rules/1300 "2025-04-26T22:12:54Z")
Hi I wrote a controller in Python that installs flow rules along multiple paths. According to my output logs, everything works fine for a while — flow rules are installed successfully on switch s12 during the first few … --- ## [P4 in the Picture of UAL & UEC](https://forum.p4.org/t/p4-in-the-picture-of-ual-uec/1290)
**Author:** [@DavideS](https://forum.p4.org/u/DavideS)\ **Replies:** 4\ **Last updated:** [April 23, 2025, 9:24am UTC](https://forum.p4.org/t/p4-in-the-picture-of-ual-uec/1290 "2025-04-23T09:24:17Z")
The UAL and UEC seem like very interesting initiatives for the networking world. Although the official specifications are not available yet, there are plenty of presentations on YT, for example, https://www.youtube.com… --- ## [How to clone packets to the control plane while continuing normal forwarding?](https://forum.p4.org/t/how-to-clone-packets-to-the-control-plane-while-continuing-normal-forwarding/1293)
**Author:** [@Zhw20250102](https://forum.p4.org/u/Zhw20250102)\ **Replies:** 2\ **Last updated:** [April 13, 2025, 3:15pm UTC](https://forum.p4.org/t/how-to-clone-packets-to-the-control-plane-while-continuing-normal-forwarding/1293 "2025-04-13T15:15:26Z")
I’m new to P4 and I have a specific requirement: When a packet arrives at the data plane, I want to send some related information of the packet to the control plane, while still allowing the original packet to continue … --- ## [Challenge on Packet Recirculation](https://forum.p4.org/t/challenge-on-packet-recirculation/1276)
**Author:** [@tveggala](https://forum.p4.org/u/tveggala)\ **Replies:** 10\ **Last updated:** [April 7, 2025, 12:07pm UTC](https://forum.p4.org/t/challenge-on-packet-recirculation/1276 "2025-04-07T12:07:37Z")
Hi, I am writing P4 code to perform deep packet inspection on incoming traffic, using the method of recirculation. I came across a logic which is able to detect a pattern, stop recirculation, and execute a desired actio… --- ## [How to build a P4 topology?](https://forum.p4.org/t/how-to-build-a-p4-topology/1282)
**Author:** [@ymymlyj](https://forum.p4.org/u/ymymlyj)\ **Replies:** 0\ **Last updated:** [March 25, 2025, 2:40am UTC](https://forum.p4.org/t/how-to-build-a-p4-topology/1282 "2025-03-25T02:40:09Z")
In my experiment, I used the following JSON file to build a triangular topology. topology { "hosts": { "h1": {"ip": "10.0.1.1/24", "mac": "08:00:00:00:01:01", "commands":\["route add default gw… --- ## [Storing payload byte in a temporary variable](https://forum.p4.org/t/storing-payload-byte-in-a-temporary-variable/1277)
**Author:** [@tveggala](https://forum.p4.org/u/tveggala)\ **Replies:** 1\ **Last updated:** [March 19, 2025, 3:34pm UTC](https://forum.p4.org/t/storing-payload-byte-in-a-temporary-variable/1277 "2025-03-19T15:34:30Z")
Hi, I am developing P4 code to do some operation on packet payload. For example, If I have a table like below, I am trying to find a way to store the packet byte in a temporary variable and do some operation on it. Is … --- ## [Dynamic Routing on P4](https://forum.p4.org/t/dynamic-routing-on-p4/1273)
**Author:** [@malldisaesar](https://forum.p4.org/u/malldisaesar)\ **Replies:** 5\ **Last updated:** [March 12, 2025, 4:14pm UTC](https://forum.p4.org/t/dynamic-routing-on-p4/1273 "2025-03-12T16:14:49Z")
I would like to ask if the P4 switch can respond to dynamic routing (e.g. ospf, rip, etc.) and inform the router about the available network neighbors of the P4 switch? For example, OSPF, where there is an exchange of i… --- ## [Switch's IP and MAC address](https://forum.p4.org/t/switchs-ip-and-mac-address/1270)
**Author:** [@akshataavk](https://forum.p4.org/u/akshataavk)\ **Replies:** 1\ **Last updated:** [March 9, 2025, 8:25pm UTC](https://forum.p4.org/t/switchs-ip-and-mac-address/1270 "2025-03-09T20:25:35Z")
Hello, As part of my project, I am working on a load balancer with 2 switches in the topology (JSON file). I followed the tutorials, and I found hosts broadcasting to send a packet from one host to another via the ports… --- ## [Queue Depth Always 0 in My INT Implementation](https://forum.p4.org/t/queue-depth-always-0-in-my-int-implementation/1269)
**Author:** [@NNy1671](https://forum.p4.org/u/NNy1671)\ **Replies:** 1\ **Last updated:** [March 7, 2025, 12:53pm UTC](https://forum.p4.org/t/queue-depth-always-0-in-my-int-implementation/1269 "2025-03-07T12:53:59Z")
I am working on an In-band Network Telemetry (INT) project using P4. However, I noticed that the queue depth in my INT metadata is always reported as 0, regardless of the network load. I have tried change the sleep from … --- ## [How to use C++/C based control plane on Tofino？](https://forum.p4.org/t/how-to-use-c-c-based-control-plane-on-tofino/1267)
**Author:** [@aoiland](https://forum.p4.org/u/aoiland)\ **Replies:** 1\ **Last updated:** [March 4, 2025, 6:10pm UTC](https://forum.p4.org/t/how-to-use-c-c-based-control-plane-on-tofino/1267 "2025-03-04T18:10:33Z")
Hi, I want to use C++/C based control plane, but I do not know how to compile it and run it with Tofino switch. Is there any tutorial helps me to learn and use it? --- ## [What happens when a table with actions defined but without any keys defined?](https://forum.p4.org/t/what-happens-when-a-table-with-actions-defined-but-without-any-keys-defined/1265)
**Author:** [@fengkeyleaf](https://forum.p4.org/u/fengkeyleaf)\ **Replies:** 2\ **Last updated:** [March 3, 2025, 8:06pm UTC](https://forum.p4.org/t/what-happens-when-a-table-with-actions-defined-but-without-any-keys-defined/1265 "2025-03-03T20:06:36Z")
Hi there, I found out an example that has some tables with actions defined but without keys defined, such as @name(".flowlet") table flowlet { actions = { lookup\_flowlet\_map; } } When we appl… --- ## [Clone3 function on stratum\_bmv2](https://forum.p4.org/t/clone3-function-on-stratum-bmv2/1261)
**Author:** [@pabloEsiiABGM](https://forum.p4.org/u/pabloEsiiABGM)\ **Replies:** 5\ **Last updated:** [February 24, 2025, 6:00pm UTC](https://forum.p4.org/t/clone3-function-on-stratum-bmv2/1261 "2025-02-24T18:00:16Z")
Hi All, I’m trying to use clone3 function on the stratum\_bmv2 software switch, but cannot detect the cloned packets using the standard\_metadata.instance\_type value of the packet. Every packet seems NORMAL type instead o… --- ## [How to get a graph of IR nodes compiled by p4c and work on it from another program?](https://forum.p4.org/t/how-to-get-a-graph-of-ir-nodes-compiled-by-p4c-and-work-on-it-from-another-program/1259)
**Author:** [@fengkeyleaf](https://forum.p4.org/u/fengkeyleaf)\ **Replies:** 10\ **Last updated:** [February 20, 2025, 9:46pm UTC](https://forum.p4.org/t/how-to-get-a-graph-of-ir-nodes-compiled-by-p4c-and-work-on-it-from-another-program/1259 "2025-02-20T21:46:58Z")
Hi all, As far as I know, p4c compiles a P4 program into a graph of IR nodes with provided arguments, like back-end target. So assume I want to write my own program that can process or traverse a graph of IR nodes after… --- ## [Prioritize BitTorrent traffic over traffics](https://forum.p4.org/t/prioritize-bittorrent-traffic-over-traffics/1256)
**Author:** [@MikVakis](https://forum.p4.org/u/MikVakis)\ **Replies:** 6\ **Last updated:** [February 20, 2025, 12:52pm UTC](https://forum.p4.org/t/prioritize-bittorrent-traffic-over-traffics/1256 "2025-02-20T12:52:02Z")
Hello everyone, I am new to P4 and i am trying to implement priority queues on my p4 app so that i am able to prioritize BitTorrent traffic over other kinds of traffic. Here is my p4 code: /\* -- P4\_16 -- \*/ #include \<… --- ## [Register manipulation](https://forum.p4.org/t/register-manipulation/720)
**Author:** [@RhEzZuS](https://forum.p4.org/u/RhEzZuS)\ **Replies:** 11\ **Last updated:** [February 18, 2025, 4:31pm UTC](https://forum.p4.org/t/register-manipulation/720 "2025-02-18T16:31:36Z")
Hello, I’ve some questions regarding registers in P4 that I’d appreciate if someone could clarify: When I use read in a register am I taking out the stored value or does the value remain stored? If a value is stored w… --- ## [Range Matching TNA](https://forum.p4.org/t/range-matching-tna/1254)
**Author:** [@layal](https://forum.p4.org/u/layal)\ **Replies:** 3\ **Last updated:** [February 12, 2025, 1:54pm UTC](https://forum.p4.org/t/range-matching-tna/1254 "2025-02-12T13:54:27Z")
Hello, I am trying to compile a program that includes range match key, and I encountered the following error: "error: Currently in p4c, the table forward\_l2\_0 cannot perform a range match on key ingress::meta.current a… --- ## [Future of P4 and buidling new device on P4](https://forum.p4.org/t/future-of-p4-and-buidling-new-device-on-p4/1250)
**Author:** [@xuoguoto](https://forum.p4.org/u/xuoguoto)\ **Replies:** 3\ **Last updated:** [January 28, 2025, 12:37pm UTC](https://forum.p4.org/t/future-of-p4-and-buidling-new-device-on-p4/1250 "2025-01-28T12:37:46Z")
Hello, I was quite excited at using p4 for a new network appliance device and especially with the performance and flexibility of Tofino chipsets, but digging deeper I am finding some dark clouds. Tofino remains the on… --- ## [Difference between P4 architectures - PISA vs PSA](https://forum.p4.org/t/difference-between-p4-architectures-pisa-vs-psa/1240)
**Author:** [@vasudhae](https://forum.p4.org/u/vasudhae)\ **Replies:** 2\ **Last updated:** [December 28, 2024, 9:42pm UTC](https://forum.p4.org/t/difference-between-p4-architectures-pisa-vs-psa/1240 "2024-12-28T21:42:52Z")
I have a query on the differences between PSA and PISA architectures as they seem to be very similar. I would like to know the exact architectures of both and their specific functions as I believe different sources state… --- ## [Intel releases Tofino source code under open source license](https://forum.p4.org/t/intel-releases-tofino-source-code-under-open-source-license/1247)
**Author:** [@andyfingerhut](https://forum.p4.org/u/andyfingerhut)\ **Replies:** 0\ **Last updated:** [January 15, 2025, 8:01pm UTC](https://forum.p4.org/t/intel-releases-tofino-source-code-under-open-source-license/1247 "2025-01-15T20:01:26Z")
See the blog article announcing this here: Intel’s Tofino P4 Software is Now Open Source – P4 – Language Consortium For more technical details, follow along in Zulip chat here: Public view of p4lang | Zulip team chat [Previous page](https://forum.p4.org/latest.md?page=1) [Next page](https://forum.p4.org/latest.md?page=3)