Questions tagged [broadcast]

For questions about broadcasting in computer networking. Use this tag when you are troubleshooting or configuring network devices in relation to broadcast.

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65 views

Bridge traffic forwarding in vlans

on a trunk, switch A having, say vlan 10 allowed and the other switch B does not. Switch B doesn't even know about that vlan. How does switch A behave in forwarding broadcasts in vlan 10? Will frames ...
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1answer
222 views

Broadcasting in L2 Switch

Hey guys, This is a Noob question. When a broadcast frame is received on a switch from a specific port, will it be automatically destined to all the ports in a switch ? ---------- (or) ---------- ...
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3answers
105 views

Graphing the number of broadcasts per MAC?

Is there a way, using free network health/analysis tools like Cacti or Wireshark, to produce a list of the number of broadcasts per MAC address or IP address, sorted by the number of broadcasts over ...
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3answers
858 views

Why do we have to connect through a default gateway in a LAN?

I'm a beginner in networking and I'm looking for answers for these questions: Why do we have to connect through a default gateway when we are connected to a LAN and want to connect to another devices ...
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1answer
3k views

What is the difference between ARP and BUM Traffic?

Suppose PC1 with IP address 1.1.1.1 and MAC address A.A.A.A wants to send a frame to PC2 with IP address 2.2.2.2 and MAC address B.B.B.B, plus there is a switch in the middle. PC1 doesn't know where ...
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2answers
852 views

How do broadcast communications work between hosts with different Subnet Masks?

Let's say I have three different hosts connected by a Layer 2 Switch: A) IP 1.0.0.1, Subnet 255.255.255.0, B) IP 1.0.0.2, Subnet 255.255.0.0, C) IP 1.0.1.1, Subnet 255.255.255.0, Who would a ...
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3answers
129 views

How would I make a client find a server with an unknown IPv6 Address?

Let me first explain my situation: I am currently in the process of trying to build a solution for managing multiple Internet of Things devices on a network. It should be possible to automatically ...
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1answer
17k views

Why can't devices in different subnets talk with each other?

I know that the layer 2 doesn't understand IP, and the broadcast domain is same. Why can't devices talk, how does it happen?
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4answers
807 views

Reducing broadcast traffic on Cisco SG300

I have a Cisco SG300 Small business switch, and the GUI interface is creating a lot of broadcast traffic: Source IP (The GUI IP): 172.16.xx.254:5353, Destination IP (Broadcast) 224.0.0.251:5353 I ...
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2answers
1k views

Does a network switch broadcast local IP Addresses?

Please consider the following scenario The router (Linksys E2000) has an INTERNET port where the main network is plugged in. The router has some ETHERNET/OUT ports where a switch, laptop or PC can ...
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3answers
2k views

Is it possible to assign network and broadcast addresses to hosts in the same network?

I know that it's not recommended to assign the network and broadcast addresses to a host but is there any way/hack using which you can assign them?
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2answers
2k views

Broadcasting traffic by 255.255.255.255 or by “subnet dot all ones”?

If a device wants to broadcast traffic does it send it to the "all ones" IP? (Which is 255.255.255.255)? Or does it send it to "the all ones of the subnet"? (For example if the subnet is 123.123.0.0/...
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355 views

What are the number of adjacencies in 10 router in mesh topology and DR/BDR topology in OSPF? [closed]

FYI: this is not a homework question. I was reading an article (http://packetlife.net/blog/2008/jun/19/ospf-network-types/) in OSPF and couldn't understand this point. "a segment containing ten ...
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1answer
682 views

What is WDS and how can it cause a broadcast storm?

Recently I was told that we leave WDS off ,whenever we can, where I work. It was explained to me that a broadcast storm is created when a routers' broadcast gets back to itself, perpetuates itself and ...
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3answers
8k views

What is the difference between broadcasting and flooding?

In Open shortest path first routing algorithm, the information about connected links is "flooded" throughout the network. How is flooding different from broadcasting?
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2answers
546 views

Understanding Broadcast address

Please validate my understanding for the following points with regard to broadcast address: 1.Broadcast address is relative to a network, so every n/w will have it's own broadcast adress(I can obtain ...
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1answer
3k views

What is the Destination Address? [duplicate]

I have some doubt in the problem which follows: Suppose a host with IP address 19.121.202.123 wants to send a packet to all the hosts in the same network. Then, what destination address should it use?...
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3answers
494 views

Broadcasting and ARP packet

Router does not send Broadcast packet. that means it does not support broadcasting. but while sending packet from computer a to computer b which is not in the same network , computer a gets the mac ...
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2answers
3k views

Does a switch MAC address table sync across all switches in the same VLAN?

Ok, I have read up about this 16K limit for the MAC address table, or better known as the CAM table, on certain switches. Lets say I have 14 different edge switches with that 16K limit, and I have ...
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3answers
440 views

Is STP used to prevent all traffic looping or just broadcast and multicast?

Let's say we have 3 switches in a logical triangle, each switch connected to the other two. This provides an opportunity for a loop when multicast or broadcast traffic is traveling here. STP is used ...
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2answers
63 views

How and what decides how many replicated packets need to be created in broadcast?

It just came across my mind that if I am broadcasting a message in my network, is it my computer, router or another node that decides to replicate the message? Also, how does that node how many times ...
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1answer
2k views

IPTV Cisco configuration for C2960

I have attached a network diagram explaining IPTV network , i have below queries to understand & configure IPTV . All ports on edge switches are configured as access ports in VLAN 101. On Core &...
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2answers
116 views

Questions about ARP

Windows homelab LAN: How come arp -d does not work consistently? I run the command and the ARP table is not cleared, yet when I run it again a few moments later it does work but leaves certain ...
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1answer
603 views

Router and broadcast domains

I am studying up for CCENT, and I'm having some trouble understanding what a basic router does. I understand one of the main functions is to split up broadcast domains. When they say it splits ...
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3answers
11k views

What are the reasons for not putting multiple subnets on the same VLAN?

I would like to know why we do not (and should not I guess) use 2 different networks on the same LAN/vLAN. From what I tried and understood : Host in network A (ex: 10.1.1.0/24) can talk to each ...
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1answer
290 views

Broadcast packet in LAN is first sent to router?

Can you confirm that if host 1 wants to send a broadcast packet, he will send it to the router first, and the router will send it to all machines to the LAN ? I need to clarify this point in order ...
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2answers
2k views

What is the difference between MAC and İP broadcast addresses?

As far as I know, they are both used to send a packet to all hosts that are connected to a local arena network. Why would anyone need two addresses to send a broadcast package?
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2answers
300 views

What WIFI AP to broadcast 3 Mbps UDP stream?

CONTEXT: We are searching for WIFI AP able to broadcast UDP stream on a maximum number of connections: 10, 30, 50, 100, 150, 200 (guess the WIFI point is different in term of price and technology ...
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1answer
836 views

Recommended Cisco storm-control broadcast and multicast threshold value for user PC

What is the recommended storm-control threshold value of broadcast and multicast on Cisco IOS catalyst switches for ports connected to users?
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2answers
9k views

What is the difference between layer-2 and layer-3 broadcasts? Please explain with an example

What is the difference between broadcast addresses ff.ff.ff.ff.ff.ff (Layer 2) and 255.255.255.255 (Layer 3)?
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2answers
546 views

Is the real broadcasting on internet possible

Am sorry if my question is silly. But I want to clear that i doesn't mean just playing audio or video from a remote server.I am asking about conventional broadcasting as exists in Television and Radio ...
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3answers
3k views

Why do we use VLAN?

According to my understanding, the network switch will look out for the specific MAC address and then it will forward the frame so basically it doesn't broadcast the frames then why do we make VLANs? ...
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2answers
315 views

Seeing traffic not addressed to me using tcpdump, how does that work?

I did a tcpdump capture, and when inspecting the reults, I saw some data I couldn't understand. Say the hostname of the box I did the capture on was box1.blah I saw traffic like this: box2.blah:...
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1answer
456 views

Spoofing Ethernet with Source as Broadcast

I was wondering the following: Assume I am attached to a switch with an Ethernet Cable and I try to spoof the source/origin MAC address of an Ethernet frame with FF:FF:FF:FF:FF:FF. How would it behave?...
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2answers
2k views

Scan all ip address on a network ARP/Ping

I'm working on a program to discover all computer on a network. What is the best way to do that My network is 192.168.1.0 There are few machines on this network and i want to know their ips Should i ...
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2answers
270 views

How are layer 2 broadcast handled

I'm reading a text (possibly outdated) and it states that large amounts of Layer 2 broadcast can degrade the performance of the workstations on the network - due to CPU interrupts. Is it possible ...
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3answers
229 views

What document or standard designated ffff.ffff.ffff as the Ethernet Broadcast MAC address?

Simple enough, question is in the title. Was trying to find an official document or RFC which designated (or reserved) ffff.ffff.ffff as the Ethernet Broadcast MAC address.
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2answers
3k views

Do broadcast (FF:FF:FF:FF:FF:FF) packets go through the router, or directly all computers on the subnet?

If you have the destination MAC address you need in your ARP cache, surely it shouldn't have to go through the router? Or is that the point - only the router can be sure to have all of its subnet's ...
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1answer
669 views

How does exactly reverse-path broadcast work?

I am not sure if I can ask this question on this website, since this is my first question here and I am not familiar with the kind of questions that can be asked here, but it is about a routing ...
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1answer
297 views

Must a broadcast request come from the same network?

I was reading about Smurf Attacks and how Smurf Amplifier Registry keeps track of servers used for amplifying the attack, then I wondered, can a request coming from anywhere broadcast it to all parts ...
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3answers
4k views

What is the difference between ff-ff-ff-ff-ff-ff (layer 2 broadcast) 255.255.255.255 (layer 3 limited broadcast)?

Please explain the flow of traffic in each case.
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1answer
495 views

How does a router/switch handle a limited broadcast address (255.255.255.255)? [closed]

Consider, there is router R connected to switches A,B,C. Each switch is connected to 5 systems. If a system in switch A sends a limited broadcast, will it be broadcasted only to the systems under ...
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1answer
150 views

Where exactly is the limited broadcast address used?

I read that limited broadcast address will be dropped by the router. So, it's not used in the layer-3 (Network layer), where IP addresses are meant to be used. So, where exactly is it used?
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2answers
11k views

What are real life examples of broadcast and multicast?

In broadcast routing, packets are sent to all nodes even if they do not want it. What is a real life example of "broadcast"? Almost everything I can think of, like GMail and YouTube, appears to be ...
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1answer
5k views

Point-to-point vs unicast, and multiaccess vs multicast/broadcast?

From Tanenbaum's Computer Networks: Point-to-point links connect individual pairs of machines. To go from the source to the destination on a network made up of point-to-point links, short ...
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2answers
99 views

How does frequency-division multiplexing deal with overlaps?

As I understand it, FDM uses separate frequency for each channel, thus A will transmit data, for instance, every two seconds and B every three seconds. But, what will be delivered on the wire in the ...
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4answers
2k views

Prevent network auto-discovery between members of VLAN

At our ISP's we use Huawei s5300 switches, and we want to upgrade our setup to accomplish the following: Place a number of different customers/users under same VLAN. Assign one static-public IP ...
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1answer
3k views

How to block broadcast packets EXITING a single switchport

I have a couple cheap external wireless APs that like to reboot themselves constantly if they get even a few broadcast packets (i am ~90% certain this is the cause, after some testing with wireshark ...
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1answer
4k views

Cisco: broadcast and multicast storm control on distribution switches

I just got some already configured switches that are giving a lot of problems on the network with port shutdowns due to storm control policies. Finally after dumping the running-config. I've saw ...
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3answers
38k views

pinging broadcast address

Iam using linux.I read somewhere in the internet that pinging the 255.255.255.255 will ping everyone in the network segment. And it will return every ip addresses in that subnet. but when i tried ...