Questions tagged [mtu]

In computer networking, the MTU (Maximum Transmission Unit) of a communications protocol of a layer is the size (in bytes) of the largest protocol data unit that the layer can pass onwards.

MTU parameters usually appear in association with a communications interface (NIC, serial port...). Standards (Ethernet, for example) can fix the size of an MTU; or systems (such as point-to-point serial links) may decide MTU at connect time.

A larger MTU brings greater efficiency because each packet carries more user data while protocol overheads, such as headers or underlying per-packet delays, remain fixed.

However, this gain is not without a downside. Large packets occupy a slow link for more time than a smaller packet, causing greater delays to subsequent packets and increasing lag and minimum latency. Large packets are also problematic in the presence of communications errors. Corruption of a single bit in a packet requires that the entire packet be retransmitted.

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Peripheral.setMTU(244) but can get only 20 bytes

I want to read more than 20 bytes of data from bluetooth to raspberry pi 3b+. I override DefaultDelegate and handleNotification(cHandle, data), and get data from handleNotification(cHandle, data). Then I convert type of data from byte to hex, and I…
陳香君
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MTU mismatch between netsh and NetworkInterface.GetIPProperties()

Related to How to get the current MTU of an interface in C# But that solution (set both mtu sizes to the same value), doesn't help in my case. There exists a problem in GetIPv4Properties(), if the mtu sizes for ipv4 and ipv6 are set differently,…
jeb
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BLE different MTU for different implementations

I have tried different implementations of BLE connection on Android. One with RxAndroidBle and another one with simple Android API. I used RxAndroidBle example app for testing. I connect to the same peripheral with the same service and…
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Why WebRTC chose RTP max packet size to 1200 bytes?

By studying WebRTC sources I was wondering why developers chose max RTP packet size as 1200 bytes. It's defined in media/engine/constants.cc, as kVideoMtu variable. Thanks.
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Can I request MTU change from peripheral to android device (even in older APIs)?

I have a hardware acting as a peripheral and I want to read all of its memory, which has 1081344 bytes. Using the standard size of 23 bytes (with 20 bytes useful for data -> see Edit to understand how it does it) it takes more than a minute to read…
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Linux gretap - net/ipv4/ip_gre.c - how to set value of key->tun_flags

I'm trying to transport over a gretap tunnel between two Linux (Centos 6) hosts some cloned IP pkts in order to feed an IDS style device. Given that PMTU discovery will not work on the cloned pkts I'm trying to transport I have to find a way to…
Mike
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How does MTU retransmission work in case of UDP

As we all perfectly know, UDP does not support retransmission along with some other things. We also aware of such thing like MTU that works basically in the following way -- when one of the network devices on the path between source and destination…
FrozenHeart
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unable to connect to AWS VPC RDS instance (mysql or postgres)

(I'm posting this question after the fact because of the time it took to find the root cause and solution. There's also a good chance other people will run into the same problem) I have an RDS instance (in a VPC) that I'm trying to connect to from…
ives
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How deterministic are packet sizes when using TCP?

Recently we ran into what looked like a connectivity issue when a particular customer of ours installed our product. We ultimately traced it to a low MTU (~1300 bytes) being configured on one of the devices in the network. In this particular…
YSK
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TCP file Transfer window size

I'm trying to reverse engineer an application, and i need help understanding how TCP window size works. My MTU is 1460 My application transfers a file using TCP from point A to B. I know the following: The file is split into segments of size…
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Set MTU in Win XP from the command line

I want to set MTU from the command line. I'm running under XP. I've tried: netsh interface ipv4 set subinterface "Local Area Connection" mtu=1300 store=persistent But it's not working. I've tried to change "ipv4" to "ip" but it didn't help. The…
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Build time configuration of Android TCP/IP MTU

I know that it is possible to read and set the MTU during runtime e.g. with: adb shell ip -d -s l l dev rmnet0 adb shell ifconfig rmnet0 mtu This has the problem that the MTU set this way does not hold after restarting the phone. So how to…
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How do i programmatically determine MTU, in C++

I am working on an application where I need to send large data in multiple UDP packets to a client, how can I determine programmatically the MTU for my UDP socket? I need to be able to do this on both windows and linux.
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I am not able to set MTU size of particular interfaces(eth0 or eth1) through Netlink sockets via NETLINK_ROUTE option

I have written a program to set the MTU size of the particular interface(say eth0 or eth1) to 1100. And the Request message is send from user space using Netlink sockets via NETLINK_ROUTE option. The message is sent successfully from user space,…
user1720713
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Sending ICMPv6 Echo Request

How can I send an ICMPv6 Echo Request Message in C#? Further I'd need to appoint the actual bandwidth, RTT, MTU on path using IPv6 (There is no DF flag in IPv6 packet) and the Packet Loss.