Effie
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  • Karlsruhe, Germany
How is UDP used in multimedia system inspite of being connectionless
7 votes

Short answer: Multimedia implements protocols on top of UDP. They implement the required functionality. Actually, they have more functionality, and are more complex than TCP. Less short answer: see ...

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STP convergence process needs detailed explanation, please
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5 votes

It is a continuous process. It is continuous because the root bridge (or any other bridge) can fail. If root fails, new root needs to be selected, and if anyone else fails, affected part of the tree ...

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Why does only the root bridge send RSTP BPDUs after sync?
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5 votes

according to comments in the question, the actual topology is two bridges: B1 (root) --- B2. According to the specification (IEEE Std 802.1w-2001, sec 17.7) Configuration Messages are transmitted if ...

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Latency between a churn and congestion event triggered in the TCP code
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3 votes

basically you are correct. packet losses are discovered either by 3 (or more) duplicate ACKs or by a retransmission timeout. The former should happen in about one RTT, provided that there are enough ...

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How do two clients of a route reflector learn about each other when no IGP/static-route is used?
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3 votes

BGP generally assumes that AS is running an IGP, to interconnect its routers. When R_Q receives a route that goes through R_P, it will have to lookup a route to R_P route through IGP as a part of BGP ...

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How in Distance vector routing one router communicates adjacent router through broadcast address and OSPF uses unicast with another?
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3 votes

There are a bunch of confusions here. Let's start with the last one. But in OSPF also get to know the routes to it's neighbors after flooding and this neighbor also share routes it's neighbors and so ...

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Why can IPv4 and IPv6 use strict source routing(in options field) and flow label respectively inspite of connectionless protocol?
3 votes

About source routing: what does connectionless or stateless mean? Each packet has a destination address. Each time a router sees a packet it considers only this particular packet. It looks up the ...

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How are IP address compared to the default 0.0.0.0/0 or ::/0 on binary level?
2 votes

The best way to think about the comparison is IMHO to have three possible values for a bit: zero, one, and "don't care". Don't care means that the bit matches both zero and one, it does not ...

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How exactly does ARQ (automatic repeat request) work?
2 votes

The receiver sends the sender a message (called acknowledgement), which says "i have received the data correctly". if the sender receives this message, the sender can be sure that the ...

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Do hosts in the same LAN know their MAC addresses?
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2 votes

short answer: the first packet is not sent out before ARP completes. In order to send a packet, the sender (usually operating system) needs to fill out its IP and Ethernet header. Thus it cannot send ...

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Slotted ALOHA probability and efficiency
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2 votes

Given the correct answer and what is written in answer of @Zac67 I interpret it as follows. Probability of X := first packet of A being transmitted successfully only in slot 6 P (X) = P ( [X1 := no ...

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In tunneling, how destination routers identify if a packet is encapsulated?
2 votes

I can't say that this applies to every tunnel imaginable, but this is a general idea how this could work. A tunnel is set up between an entry point and an exit point. In this case the outer packet ...

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If person A has a network 123.123.123 and person B has a network 123.123, what happens if they both assign an IP to a device of 123.123.123.123?
2 votes

This should never happen. If it happens, the behavior is undefined, i.e., network may not work in a number of ways. IP addresses are hierarchical and must be assigned hierarchically. All IP addresses ...

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why can't my PCs ping each other?
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2 votes

according to your configuration, all your PCs are in the same local area (layer 2) network aka subnet. Since they think they are in the same subnet they think they should reach each other using layer ...

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Is it possible for TCP can accept out of order segments?
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2 votes

I still do not understand the question fully and thus point out where misconception comes from. But, does this clarify things? Note, that TCP is stream based, i.e., on the sender side (left) upper ...

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RSTP Network Switches Port Base MAC Address
1 votes

If I understand correctly, you are looking for section 7.12.7 in 802.1D. Section 7.12.7 specifies that BPDUs (together with two other types of frames) are processed as if they were received by a ...

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ARP Questions (Packet Types, Ethernet, Cache, Gratuitous)
1 votes

An addendum for the reference: rfc5226 speficies IANA registry for ARP

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Do segments at the transport layer contain IP information?
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1 votes

This is a case of, "in theory there is no difference between theory and practice, ..." Usually, applications interact with operating system's network stack using an abstraction, called ...

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What happens to the unused IP addresses in the subnet that falls in between two routers?
1 votes

This is not a direct answer to the question, but judging from the comments, I think there is a confusion between address aggregation and address assignment. update: i think you can think of this in ...

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Router interface on same subnet
1 votes

a router can be physically connected to the same subnetwork with different interfaces. routers, that implement dynamic routing protocols, may not work if a single router has two interfaces facing the ...

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Does a router work both on Layer 2 and Layer 3?
1 votes

Why can't we say router works both at Layer 2 and Layer 3? This is implied. Basically, when we say that a device works on layer N, we actually means that the device implements all layers up to ...

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Processing received SACK information in case of reordering
1 votes

i think the short short answer is: an example of what sender can do is here rfc6675 First, TCP receiver does not process SACK fields. SACK, as ACK, is sent by the receiver, i.e., receiver creates ...

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Why isn’t there routing inside subnets?
1 votes

This also depends on the definition of subnet. Based on the question, I assume that subnet refers to a single layer 2 domain / LAN / network. In this case packet is not routed based on IP addresses. ...

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Why the two connected routers via PPP doesn't use ARP but ethernet use ARP?
1 votes

This question is kinda impossible to answer. Different protocols use different means of transmitting its data. OSPF uses IP, RIP uses IP/UDP, IS-IS uses layer 2 directly. Also, addresses on multicast-...

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How is P actually chosen in P-persistent CSMA?
1 votes

So, this question actually asks two question: how to find the optimal value of p given a value of p, how to set this value of p on any participating system For the first question: I would say that ...

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Why client will send a RESET when it is closed state?
1 votes

In order to see why this is happening we need to consider these two things: TCP is stateful, in that both end-points of the connection are holding connection state. When the connection is closed, ...

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Why would I need fq_codel?
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1 votes

there is really no short and simple answer to this question. Here is a general idea, but to answer this question it might be necessary to understand exactly how a number of things work and how they ...

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Why is the last ACK needed in TCP four way termination
1 votes

There are 2 pairs of FIN/ACKs because in TCP each direction of the stream is closed separately. When A sends a FIN to B, it means that A will not send any more data to B. The connection can remain ...

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The difference between data frame and BPDU in STP
1 votes

it seems to me like a confusion with terminology. First, what is a frame? In OSI model each layer has a different name for a packet and at layer 2 this is called frame [*]. a better explanation from ...

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Congestion control behaviour of TCP Reno
1 votes

When TCP Reno sender gets 3 duplicate ACKs, it enters a so called fast retransmit mode. The idea of this mode is that a) since ACKs are delivered it indicates that packets are leaving the network b) ...

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