Questions tagged [mtu]
For questions about or in relation to the maximum transmission unit (MTU).
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Why MTU setting change not showing any meaning change in file transfer via tcp?
I performed a test in which I transferred a file of 1GB by opening a tcp port on destination server with MTU 1000.
then I tried to change the MTU from 1000 to 9000 and the total time duration of 1GB ...
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How can a router know the MTU of the next router?
https://www.cloudflare.com/learning/network-layer/what-is-mtu/
Suppose Server A and Computer A are connected, but the data packets
they send to each other have to pass through Router B and Router C
...
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Brocade 7450 - set MTU to 9000
I have brocade icx 7450.
I already enabled jumbo frames to increase MTU packets on switch.
But unfortunately I am not able to change MTU size of port which I want. When typing after choosing interface ...
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Sanity Check: Changing MTU on Wifi Endpoints (computers) should be a LAST resort, right?
A client of mine has an organizational network that is comprised of a lot of Ubiquity gear, primarily switches and wireless routers to power their network, with a Sophos XG firewall at the border.
...
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What is the MTU used for in EIGRP? [duplicate]
A lot of sources mention that MTU is included in the EIGRP packets but is not actually used for any path selection calculations. I've also read somewhere that it was supposed to be used as a ...
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525
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GRE tunnel bridging and MTU mismatch
Background
My workplace has 2 office areas which is only 200 meters away from each other. They have their own local networks, their own Internet connections, with routers configured to fallback to the ...
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Can a jumbogram (giant data packet) be used at a large scale (in WAN for example)?
There are many scientific paper for Jumbo frame, even more, some real implementations and deployments. But it is not the case for Jumbogram !!
Jumbo frame (geant frame) for Layer 2; Jumbogram (geant ...
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What's the difference between MTU and MRU ? How come people talk so often about MTU and little consideration is given to MRU?
I don't understand why MRU isn't mentioned as frequently as its counterpart MTU. Are they always arranged to have the same value on a device ? A few days ago I noticed that my Windows machine accepted ...
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MTU mismatch scenario, two hosts handle in a different way ingoing packets bigger than local interface MTU. How does MTU really work?
I’ve been struggling with the MTU topic for a while and I still can’t get how it really works. The majority of books that I read and the courses that I attended all seem to treat this subject in a ...
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Does MTU setting affect sending, receiving, or both?
Consider the two devices:
A: PC, NIC MTU is set to 1500
B: Router, MTU of relevant interface is 1478
Now if A sends a frame of length 1500 to B, something might go wrong. But what if I set A 's MTU to ...
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What is the maximum safe UDP payload size over IPv6? [duplicate]
I am developing a networking library (that uses exclusively UDP) and I want to support both IPv4 and IPv6 by using a dual-mode socket. I want to limit the size of the packet user can send to a value ...
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Why is Packet Size Limited?
I was reading: this answer to "Maximum packet size for a TCP connection", where it says:
The absolute limitation on TCP packet size is 64K (65535 bytes), but
in practicality this is far ...
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Packet capture shows packets larger than MTU
I have been doing some tests with two CentOS computers located in a local network and I don't understand the results. We have a simple application where a client (x.y.z.204) sends text strings to a ...
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Help me understand why to decrease the MTU size
Why I should decrease MTU on interfaces instead of increase it when ipsec encapsulation is present, GRE or some other?
The way I see it: a packet of 1500 bytes comes to the router, then there is IPSEC ...
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tcpdump output with bad length indicator present
Could someone help me interpret this tcpdump udp packet output? We are getting out image so I'm wondering why we are seeing this message. Is the packet length indicated by "length 1500)" or ...
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GRE, guarantee 1500 bytes MTU for end hosts
Is it possible to achieve 1500 byte MTU at the end host connections ignoring fragmentation overhead in this simple scenario using GRE.
I would like to configure R1 and R2 to do the fragmentation ...
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Difference between MTU and max length of PDU [duplicate]
I was studying and came across the concept of MTU and I don't know how to differentiate it with the maximum length of a PDU.
I understood that the max length of a PDU is the maximum amount of ...
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490
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Difference beetween MTU, ipv4 MTU and mpls MTU
In a Cisco configuration, what is the difference beetween the MTU, ipv4 MTU and the MTU configured into the mpls section of an interface ?
interface X
mtu 9214
ipv4 mtu 9180
[...]
mpls
mtu 9200
!...
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1
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300
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MTU changing after first ping
I noticed kind of strange behaviour and my knowledge doesn't have answer for it.
So I want to know MTU. First ping:
ping -c 1 -s 1800 -M do google.com
PING google.com (216.58.209.14) 1800(1828) bytes ...
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How exactly does Path-MTU Blackhole Detection work?
I'm currently trying to understand how the Path-MTU Blackhole Detection really works.
From what I understand: You send rather big packets, starting at like 1460 Bytes (TCP example) and wait for ...
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OSI model transition between layers (data chunking across layers)
There is something I don't understand regarding the OSI model.
From what I learned, sometimes information will need to broken down into smaller pieces of information.
My question is - let's say that ...
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381
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routing MTU size and encapsulation?
I did some research for my question beforehand such as this one:Cisco routers THROUGHPUT - MTU and packet size
however, it seemed not precise to explain the doubts in my head.
My primary goal is to ...
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how data are fragmented based on MTU and MSS?
just to be clear.. if a sender wants to send a data of 1800bytes ( assuming MTU be 1500bytes
so MSS = 1500-40 (taking min ip and tcp header) = 1460bytes)
Then there will be three segments 750 + 750 + ...
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2
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2k
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Vxlan with internet access - possible because of high MTU?
So i was wondering, because VXlan requeres a high mtu to work properly (some set it even as high as the max configurable MTU (9000ish)), how would providing internet access for these nodes/servers ...
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Minimum MTU size on Ethernet and minimum Ethernet frame size
I am a bit confused about the understanding of the relationship between minimum MTU of MTU and minimum Ethernet frame size.
We know that the maximum MTU of Ethernet is 1500 Bytes which makes the ...
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Confusion about MTU
I am studying about IP fragmentation and MTU. What I know is MTU is the property of Physical medium, as in the amount of data it can process without having to fragment the data. The default MTU on ...
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254
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MTU size for PPPOE with QinQ
i used at as A pppoe server
i have used QINQ secend tag in rotuer
interface TenGigabitEthernet2/0/0.904
description Cust1-QINQ
encapsulation dot1Q 904 second-dot1q any
pppoe enable group PPPOE-...
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MTU mismatch in the network
The issue is on our routed network for one site to another.. The clients can't access a secure routed websites.. Simply the DNS server will resolve but the web page will not load.. All our server and ...
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Create a VXLAN with MTU = 1500?
I have a cluster of servers interconnected with 10 Gbps fabric interfaces (ens1f0, MTU 1500). I've set up a VXLAN interface across the cluster using default settings (MTU 1450). For reasons of ...
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MTU the most Confusing Networking term. Lot of questions
I have ton of questions and i feel this is most confusing term for me. The more i read the confusion deepens.
I am not able to connect dots. please help.
Do we need MTU adjustment with EoMPLS/dot1q ...
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Question about MTUs vs maximum frame sizes - what is their difference?
I am currently studying networking at university and I have a question about MTUs and maximum frame sizes.
What is the difference between the MTU and the maximum frame size? This Wikipedia article ...
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Confusion about data fragmentation/MTUs - why was it introduced in the first place?
I am currently studying networking as a part of my bachelors and I am a bit confused about why fragmentation/MTUs are necessary. In my lecture slides, it only says "Fragmenting if necessary" under the ...
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MTU 9000 and 1500 when machines with MTU 1500 send data to machines with MTU 9000
we have some machines in the cluster
linux machines as Linux_a , linux_b are configured with MTU 1500
while linux machines - linux_1 and linux_2 are configured with MTU 9000
so
linux machines - ...
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1k
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Which interfaces do I need to configure to change MTU of Cisco Site-to-Site VPN
I have a number of Site-to-Site VPN tunnels in my network configurations. They are configured using Cisco ASA devices.
To resolve some performance issues I am trying to change the MTU for traffic ...
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2k
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How do both sides know the MTU
If I have ComputerA that has their networking interface set with an MTU of 1500 and ComputerB has a network interface with an MTU of 1200 is there any way for ComputerA to know that ComputerB's MTU is ...
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How does a router calculate a MTU [duplicate]
For a given link type, how would a router calculate it's MTU?
I initially thought of it taking a brute force approach, using a binary search to figure out the point at which the link fails to support ...
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Difference between Giant Frame and Jumbo Frame
Can someone enlighten me the difference between Giant Frame and Jumbo Frame?
From what I hear, Giant frame is a frame with the size greater than 1518 Bytes excluding Preamble, Frame Delimiter and ...
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why mtu cmd ping test result depends on mtu setting on router?
why MTU test results depend on MTU setting on my router??. ex: when I set MTU on my router for 1440, the result is "1440-28=1412", the first MTU gives replay, so how can I know the best MTU??.
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What happens if the IP MTU is smaller than the MSS?
Let's say i configure the MSS > IP MTU. Even if it doesn't make sense, would this be possible?
Assuming i then try to send a file of the size of MSS or bigger, the network layer will receive the data ...
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Why maximum length of IP, TCP, UDP packet is not suit?
From many tutorials, I get follow knowledge(maybe I'm misunderstood) :
maximum of an Ethernet packet is about 1500 bytes.
maximum of an IP packet is about 65535 bytes.
maximum of a UDP packet is ...
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What does MTU depend on?
I'm trying to understand what factors determine the MTU. For instance, why 802.11 has MTU of 2304 while Ethernet MTU of 1500? Are there restrictions of the physical medium or arbitrary design ...
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Nexus 3172T MTU
I am attempting to set the L3 mtu on a Nexus port.
The mtu option is only available if I set "no switchport" which then prevents me configuring VLAN related settings.
Am I missing something obvious? ...
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How does a router know the MTU of a network?
I've done several exercises where you're given the MTU of a net or subnet, but I wonder how routers know the MTU of the nets they're connected. I've learnt that in OSPF protocol this information is ...
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Fragment Table Overflow router cisco (strange Behavior) [closed]
I am getting this error message many times in my Router Cisco :
%IP_VFR-4-FRAG_TABLE_OVERFLOW: Tunnel1: the fragment table has reached its maximum threshold 16
%IP_VFR-4-FRAG_TABLE_OVERFLOW: Tunnel1:...
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Advantages of setting the MTU and MRU at the server-facing port?
Let's say, that one has a following network topology:
www-server[eth0] <-> [ge-0/0/0]MX-router[ge-0/0/1] <-> Internet
What are the advantages of setting the Maximum Transfer Unit and ...
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Cisco 3560 Jumbo Frame
looking for some clarification on the jumbo frame config for a cisco 3560 switch.
I understand that by enabling jumbo frames, it enables it on all ports for entire switch, what happens to devices ...
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Is the MTU of Ethernet still 1500 Bytes?
So basically do the modern routers in the internet still use 1500 as the MTU of Ethernet? or the 1500 Byte was for the old days?
What I'm asking here is what is the MTU of Ethernet in modern Networks?...
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3
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Verifying current network MTU sizes
Hello Network Engineers,
I've been tasked with identifying weather or not my current network has (egress / ingress) MTUs greater than 1400.
My question is, what is the best method of capturing/...
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Can the MTU size change on a local network if non of my software attempt to do that?
From the ip manual page (man 7 ip), we read that the MTU may change over time.
When PMTU discovery is enabled, the kernel automatically keeps track of the path MTU per destination host. When it is ...
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Is Path MTU Discovery(PMTUD) really efficient?
As i know, PMTUD uses ICMPv6 to find minimum MTU value in the network path.
I understood why IPv6 doesn't allow fragmentation (by reading this article), but PMTUD doesn't look like good manner.
here ...
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