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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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2answers
30 views

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

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
95 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
40 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
25 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
72 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
51 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
50 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?
3
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1answer
63 views

Internet Protocol version 4 (IPv4) padding?

Where is ip padding insert in ip data-gram format, after payload?
2
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3answers
59 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
646 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
516 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
37 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
68 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 ...
0
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1answer
46 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
48 views

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

What is Ether? is it the same meaning with Ethernet?
3
votes
1answer
59 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 ...
3
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3answers
187 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 ...
4
votes
1answer
454 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 ...
0
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0answers
158 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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votes
1answer
176 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
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1answer
59 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 ...
6
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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 ...
12
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8answers
5k 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
384 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....
0
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1answer
43 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 ...
1
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2answers
704 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
293 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
43 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
100 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 ...
1
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1answer
52 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 ...
0
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1answer
247 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 ...
1
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0answers
120 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
48 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
234 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
39 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
145 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
669 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
610 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
188 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 (...
0
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1answer
71 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 ...
2
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1answer
409 views

ARP broadcast vs Default Route

Assume a host is connected to a router. If a host pings an unknown unicast address that's not in host's routing table, which one of the following is going to happen? (Assume the default route points ...
1
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1answer
133 views

DHCP packets - aren't they always supposed to be broadcasted?

So, as I understand it, all DHCP/BOOTP REQUEST packets are supposed to be broadcasted (255.255.255.255), because that's really the only way to communicate back and forth with a host on a LAN that ...
4
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2answers
2k views

CSMA/CD vs CSMA/CA vs MACA

The title pretty much explains what I'm trying to understand. What is the difference between CSMA/CD, CSMA/CA and MACA. I've read from different sources that MACA doesn't solve Hidden Terminals, or ...
0
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2answers
121 views

Go Back N protocol

I am trying to understand the working of Go-Back N using this website:- http://www.ccs-labs.org/teaching/rn/animations/gbn_sr/ Here, suppose we are sending frames 1,2,3,4,5,6 (window size 4) and in ...
1
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1answer
225 views

Max hosts of subnet IPv6

When a interface takes an IPv6 address it does the DAD mechanism. A NS will be sent to the multicast address "solicited node multicast group address". If there is another interface in this multicast ...
3
votes
1answer
4k views

Why does source port and destination port differ, in my network communications?

I just knew by theory how two host communicate through a port and a protocol, and i always thought that they must be using the same port number aat both ends to communicate, but looking at the ...
1
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1answer
39 views

How does the encrypted Wi-Fi protocols relate to ethernet?

More exactly: Which protocol is embedded into which? The relevant Wiki page describes only the protocol, but not its relation to the ethernet. It isn't even made clear if it uses embedded ethernet ...
0
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1answer
206 views

Difference between packet loss and ACK loss [duplicate]

I want to ask a question that seems to confuse me. I have a question in my self-study "Computer Networking" book which distinguishes a packet error from ACK error for a Selective Repeat protocol and ...
2
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1answer
314 views

why the two hosts with same “Subnet Address” in LAN can be pinged?

In Subnet Addressing of TCP/IP Illustrated, Vol. 1: The Protocols, there is description: This makes sense because class A and class B addresses have too many bits allocated for the host ID: 16384 - 2 ...
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0answers
29 views

Who assigns the Coordinator Node in Zigbee mesh network?

In the zigbee mesh network, who assigns the coordinator node and the FFD? Is there any algorithm by which this is done?