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Use this tag for questions about network protocols published in a Standard or RFC. Do not use this tag merely because the question mentions a networking protocol in it. Questions with this tag *could* be closed if they do not explain why the question is relevant and important to answer; this is ...

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1answer
20 views

Are there any advantage of using multiple threads for a file upload, for an internet connected node? [on hold]

I got asked in an intervew recently to design a file upload feature. After initial discussion, The interviewer asked if I can design for multiple threads. My thought was, As the network bandwidth is ...
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2answers
47 views

How do you know which layer-2 protocol is in action?

We know that the packet contains an IPv4 header, by reading the EtherType field. My question is, how does the NIC know the Layer 2 protocol is Ethernet to begin with? If there are two different Layer ...
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1answer
24 views

Whether every TCP packet have a Ack Reply?

The TCP Acknowledgements you see in the diagram's green arrows, have ACK numbers separated by 3000(two 1500 bytes). I have a question, why the Ack number is separated by two packets? Or is it just ...
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2answers
2k views

Where is Ping's “round-trip time” stored in the IP header?

If we use ICMP's ping, we know the TTL and round-trip time are stored in the IP header. In the below IP header map we know TTL's location, but where is the round-trip time? Is it stored in Options?
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2answers
29 views

Where is the data fragmented into pieces, and based on what rule?

When data from the application layer pass to transport layer: data may be fragmented into pieces of data, and then the transport layer will be added to the transport layer header (may be TCP header, ...
3
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1answer
109 views

Linux TCP stack repeatedly sends “TCP window update” without acknowledging any data

My company is developing its own TCP stack for low-latency purposes and one of the tests involves running 128 instances of ncat on Linux 4.11 to listen to ports 55000 through 55127 and sending data in ...
2
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2answers
26 views

How to understand the `Data in the Network Access Layer, it will be break up into smaller units.`?

Today when I read a book, there is a sentence: Data in the Network Access Layer(TCP/IP's layer 1/4), it will be break up into smaller units. I can not understand this statement, does it mean the ...
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1answer
58 views

How IP datagram know its upper layer protocol?

Hi I'm a newbie in networking, I just want to know how IP datagram know its upper layer protocol is TCP or UDP? I know there is protocol field inside the IP datagram header that can tell the layer ...
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1answer
73 views

Iterative queries of a default DNS server

I have just started to study networks and I have a confusion about what happens when a default DNS server does iterative queries to other DNS servers to resolve a name in an IP address. I am very ...
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2answers
42 views

How does the server know how to respond to a UDP packet? [closed]

As far as I know, UDP ports and OS sockets are mapped only by the (local port, local address) pair. In other words, the receiver side's OS does not keep a state of (remote port, remote address) pair (...
2
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1answer
150 views

Why are DHCP ACK and REQ messages broadcast in Link Layer?

When I look at the protocol, I see that DHCP Request and Acknowledgement are both broadcast in the link layer. However at that point, both sides actually know each other's MAC addresses. Why do they ...
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3answers
59 views

Why do we need an ethernet MAC address? [duplicate]

Don't think it's a duplicate. I've searched really many articles and couldn't find the satisfying answer. I understand : how ARP works MAC address is an unique address for each NIC IP is network ...
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2answers
34 views

Network Packet that allows maximum throughput

I created a basic wireless system between two microcontrollers. Each uses the on-chip UART and an HM-TRP radio module to communicate with each other. Eventually I'll have a master-slave setup where ...
2
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2answers
94 views

If the IPv6 address will be strictly based on EUI-64 logic then is there any real need of Neighbour Discovery Protocol?

I am building my fundamentals on IPv6 and have realised the multicast group is nothing but FF02::1:FFXX:XXXX. Here xxx is nothing but 24-bits of Mac-address (48 bits) with simple 7th bit magic. ...
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3answers
62 views

Do OSI and TCP/IP models use the same protocols?

OSI is known for using hundreds of protocols to do its job. Both OSI and TCP/IP have Transport and Network(Internet) layers where TCP and IP protocols work respectively. It is clear that TCP/IP model ...
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1answer
55 views

What Are the Advantages of Static IP Addresses?

As there are two types of IP addresses, why static addresses are harder to maintain, and if they are so what is their advantage to have one instead of dynamic IP adresses?
4
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1answer
90 views

Internet Protocol version 4 (IPv4) padding?

Where is ip padding insert in ip data-gram format, after payload?
3
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3answers
79 views

Do TCP implementations retransmit bytes or segments?

The sequence number and acknowledgement number in the TCP header is specified to contain byte counts. However, a lot of resources, including RFCs, say that "lost segments are retransmitted" instead ...
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4answers
677 views

Why is the Ethernet Connection Symmetric?

I know that cable connection (DSL) is asymmetric, there is a certain bandwidth on the channel, and for a better user experience, they allocate a bigger portion to the downstream. I suppose Ethernet ...
4
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1answer
546 views

Do we send ack frames in ethernet? if not then how does a router know if its neighbors are down or not?

So first off, do ethernet sends ack frames or not? if it doesn't : then how does a router know whether its neighbors are down or not? if it does : then is it cumulative ack with an ack timer or one ...
2
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1answer
45 views

Ethernet's frame format, length or EtherType?

Ethernet defines a 2 byte header for the payload's length in its frame format. This header has an ambiguous meaning: if smaller than or equal to 1500 it represents the payload length. if ...
0
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1answer
79 views

How do ICMP packets travel in a networks?

Questions: I'd like to know how ICMP packets travel in a network? Are they encapsulated within IP datagram? The RFC 792 doesn't explicitly states the layer of ICMP. Are ICMP messages sent using a ...
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1answer
55 views

Computer networking dwdm [closed]

Why do we use digital cross connects, which define permanent cross connect between source and destination in core network while the PSTN allocated circuits dynamically as both are types of circuit ...
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1answer
52 views

What is Ether? is it the same meaning with Ethernet?

What is Ether? is it the same meaning with Ethernet?
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1answer
72 views

How does SDN Controller know the IP address from a packet?

We've always said that SDN Controllers are "Protocol-less", they don't need to know the packet's encoding to switch it or, controllers can be routed packets by the IP Address and the IP Address used ...
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3answers
422 views

How is tcp/ip implemented

Well, first of all I am new to networking. And I have studied the layered structure of tcp/ip protocol stack. I know that the layered structure is an abstract model, but I didn't know how the ...
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1answer
459 views

How do data packets travel without merging?

I have been very interested in networking for quite a while, and I have been wondering this question. I've been thinking about this in complete binary, meaning how does a 0 of a data packet not get ...
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0answers
181 views

Selective Repeat protocol's window size

Hi I'm a newbie to networking, I can understand the differences between Go-Back-N and Selective Repeat protocol on transport layer.I'm confused with Selective Repeat, I know receiver might not be able ...
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1answer
356 views

What is the EtherType of a BPDU frame sent by a switch which runs Spanning Tree Protocol

I want to know what is the EtherType field of a BPDU frame in various versions and variants of the Spanning Tree Protocol.
4
votes
1answer
61 views

Active Queue Management

Was reading through one of the papers on Active Queue Management.Just hit upon this paragraph, which I couldn't understand.Got confused at this part: https://queue.acm.org/detail.cfm?id=2209336 ...
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6answers
2k views

Why do we need FTP when there are layers to transmit data?

In OSI, there are layers for routing, encapsulating and transmitting the data. Then why do we need FTP? I read the following definition of FTP in books: FTP is used for transferring files on ...
13
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8answers
6k views

Does TCP open a new connection for every packet that is sent?

This might be a silly question but a me and few buddies have been discussing the potential limitations of TCP. We have an application that is going to listen for clients (think of a gateway) and route ...
5
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4answers
386 views

Port Numbers related doubt

Assume we have two browsers (Chrome and Firefox) running simultaneously, and both are requesting a web page. Lets assume Chrome is requesting www.facebook.com, and Firefox is requesting www.youtube....
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1answer
44 views

TCP Vegas: formula for expected number of backlogged packets

While reading Issues in TCP Vegas by Richard J. La, Jean Walrand and Venkat Anantharam (available online here), I stumbled across the following sentence (Part 3 - Rerouting, page 4): When the ...
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2answers
936 views

What is the difference between TCP/IP protocol and TCP model?

We know that there are two models OSI and TCP model. But TCP/IP protocol is different from TCP model as this protocol used in both OSI as well as TCP model. So why the two are named the same is ...
2
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1answer
489 views

How to understand the sequence number of segments in TCP termination process in TCP/IP Illustrated, Volume 1: The Protocols (2nd Edition)?

I read about TCP/IP Illustrated, Volume 1: The Protocols (2nd Edition) 13.2 TCP Connection Establishment and Termination, and the following picture shows the TCP connection and termination process, ...
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0answers
45 views

Slotted ALOHA with Uniform Distribution Backoff

Let us consider a slotted ALOHA system with a finite number of N nodes, with each node having an infinite buffer. The transmission probability is p and the packet arrival is Poisson distributed with a ...
1
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1answer
120 views

What is the correct CSMA p-persistent algorithm?

After reading some books and sources I understand that the CSMA p-persistent protocol works like this: if the channel is idle, it transmits with probability p, and with probability 1 - p it defers to ...
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1answer
66 views

Rationale for EXCLUDE mode in mutlicast IGMPv3 / MLDv2

Both IGMPv3 and MLDv2 have an include and an exclude mode, where a multicast listener can specify to either listen only for packets from some list of source addresses (include) or only for packets ...
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1answer
275 views

How to use Dijkstra's Algorithm? [closed]

I am trying to do as many examples as I can to practice Dijkstra's Algorithm however, I am confused with this particular problem as I do not know how to go about it. To solve questions like these, how ...
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0answers
182 views

Why SYN-RECEIVED sends reset on not acceptable ACK?

The tcp protocol actions on arriving segment vary. The set of choices includes: silently drop segment kill connection (i.e. enter CLOSED) send reset (and maybe kill connection) send dup/null ack (etc)...
2
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1answer
50 views

What type of PDU are IS-IS LSPs?

What is the proper classification of an IS-IS link state PDU? Here are some suggestions: Cell: Not applicable because TLVs are used. A cell must have a fixed length, according to ITU-T I.113 1997-06 ...
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2answers
370 views

When should TCP send a cumulative acknowledgement?

I am simulating TCP and I don't know when it should send the Acknowledgment. For example as soon as a segment dropped should we send the Acknowledgment or should we take some time, maybe the segment ...
1
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2answers
314 views

How sliding window protocols handle duplicate packets caused by extreme network delays?

Let's say there is a network that sometimes delivers data with extreme delays. And there is a protocol that uses a "sliding window" algorithm for tracking packets acknowledgement. And imagine such a ...
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1answer
40 views

In an agentless SNMP device, at what level does the SNMP agent run? In the Hardware? In the Operating system? Or somewhere else?

I know that there are devices that now support agentless SNMP configuration. However I believe that the SNMP agent application has to run somewhere. It has to be some code running somewhere stored on ...
1
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1answer
183 views

When X.25 or ATM were used in ISP networks or Internet backbone was the protocol running over this layer still TCP/IP? [closed]

What was the protocol usually used on top of X.25 and ATM or even Frame Relay Networks when those were commonly used? Was it also TCP/IP protocol stack or some other protocol stack? From what I know ...
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2answers
884 views

Is the CSMA/CD protocol active in modern ethernet networks that use LAN switches? If it is active, does it ever detects a collision?

I am interested to know if the CSMA/CD protocol is still active in modern Networks and if it is active why and what is his role now?
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2answers
675 views

What does the naming convention for ethernet standards mean: 1000BASE-T , BASE-TX, BASE-SX, etc.? What is the meaning of the components of the name?

I understand the number in the naming convention. The number represents how many Megabits per second can the standard support. However, I do not understand the rest of the naming convention. What do "...
4
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1answer
231 views

How does a NIC know where the start of a frame is?

A question popped into my head today and after a quick few searches on google, I have no idea. When a device is sent a frame there is a layer 1 header/preamble saying the length and layer 2 protocol (...
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1answer
74 views

Ethernet without csma/cd. Lets imagine

Nowadays ethernet uses csma/cd. But Have we ever used ethernet without csma/cd? What protocols used CSMA? What would be without a collision detection? They should somehow to know about transission ...