[zeromq-dev] Limited UDP Message Size

[Doron Somech]

Make sense, do you want to try and make a pull request?

On Tue, Jan 14, 2020 at 11:40 AM Stephan Opfer <opfer at vs.uni-kassel.de>
wrote:

> Okay, so then my suggestion would be ~2^16 bytes as maximum value, but a
> default value of 8191 bytes or lower. Plus the option to change the value,
> in order to make libzmq applicable in local network applications that use
> larger UDP messages (e.g. a team of service robots cooperating in your
> household). Further an API level error message or assert, that shortly
> explains the issue when sending UDP messages, larger than the value set.
>
> Thoughts?
> On 12.01.20 23:04, Greg Young wrote:
>
> If not clear ... if you are on a network *you control* is very different
> than being on one you do not.
>
> On Sun, Jan 12, 2020 at 5:02 PM Greg Young <gregoryyoung1 at gmail.com>
> wrote:
>
>> This is correct ... Some things may not accept/forward it.
>>
>> Beyond that its common for things to get *added to it* thus you want to
>> be below. Consider a case where its being wrapped (tunneling is a good
>> example).
>>
>> Over the internet the maximum completely safe size is even smaller
>> around 500-600 bytes :O You can usually get above this but +- 1k is about
>> the limit.
>>
>>
>> On Sun, Jan 12, 2020 at 4:42 PM Stephan Opfer <opfer at vs.uni-kassel.de>
>> wrote:
>>
>>> Ah okay. I read some posts about MTU and fragmentation. So in theory
>>> 2^16= 65536 Bytes should be possible, but not all nodes will accept such
>>> large UDP packets and support the fragmentation of it?
>>>
>>> FYI: My use case is that of a local network (IOT + Autonomous Robots)
>>> and increasing the size would help me. :)
>>> On 12.01.20 13:25, Doron Somech wrote:
>>>
>>> We can increase it to around 65,000 bytes, however, large UDP packets
>>> would probably be dropped when traveling outside your local area network.
>>> The safe size for the UDP packet to travel outside of the local area
>>> network is around 500 bytes.
>>> If you do want to use large UDP packets on your local area network you
>>> might want to increase the network MTU (jumbo frames) for better delivery.
>>>
>>> For example, some AWS instances support 9001 bytes MTU for
>>> inter-instance communication.
>>>
>>>
>>> On Fri, Jan 10, 2020 at 3:25 PM Stephan Opfer <opfer at vs.uni-kassel.de>
>>> wrote:
>>>
>>>> Hi all,
>>>>
>>>> since 2016 there is this issue
>>>> (https://github.com/zeromq/libzmq/issues/2009) about some limitations
>>>> of
>>>> the udp_engine in libzmq.
>>>>
>>>> Is it possible that someone at least will increase the "#define
>>>> MAX_UDP_MSG 8192" in libzmq/src/udp_engine.hpp to some reasonable
>>>> value?
>>>> For example "ZMQ_MAX_MSGSZ" from the zmq context option, which is
>>>> MAX_INT.
>>>>
>>>> Maybe, someone could spare some time at the Hackathon... ;-)
>>>>
>>>> Greetings,
>>>>
>>>>    Stephan
>>>>
>>>> --
>>>> Distributed Systems Research Group
>>>> Stephan Opfer  T. +49 561 804-6279  F. +49 561 804-6277
>>>> Univ. Kassel,  FB 16,  Wilhelmshöher Allee 73,  D-34121 Kassel
>>>> WWW: http://www.uni-kassel.de/go/vs_stephan-opfer/
>>>>
>>>> _______________________________________________
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>>>> https://lists.zeromq.org/mailman/listinfo/zeromq-dev
>>>>
>>>
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>>>
>>> --
>>> Distributed Systems Research Group
>>> Stephan Opfer  T. +49 561 804-6279  F. +49 561 804-6277
>>> Univ. Kassel,  FB 16,  Wilhelmshöher Allee 73,  D-34121 Kassel
>>> WWW: http://www.uni-kassel.de/go/vs_stephan-opfer/
>>>
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>>> https://lists.zeromq.org/mailman/listinfo/zeromq-dev
>>>
>>
>>
>> --
>> Studying for the Turing test
>>
>
>
> --
> Studying for the Turing test
>
> _______________________________________________
> zeromq-dev mailing listzeromq-dev at lists.zeromq.orghttps://lists.zeromq.org/mailman/listinfo/zeromq-dev
>
> --
> Distributed Systems Research Group
> Stephan Opfer  T. +49 561 804-6279  F. +49 561 804-6277
> Univ. Kassel,  FB 16,  Wilhelmshöher Allee 73,  D-34121 Kassel
> WWW: http://www.uni-kassel.de/go/vs_stephan-opfer/
>
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