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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337 views

Does other hosts “learn” mac-ip entries on broadcast

in this post Learn MAC addresses via replies to other hosts requests I see that if host A sends an ARP query about host B, host C that resides in the same LAN will not learn host B MAC address, but ...
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3answers
166 views

Does a dial-up modem support multiple users?

Since I have never worked with a dial-up modem, I was wondering if it created an internet connection for only one user, a point-to-point connection, or if it also supported multiple users.
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Doesn't a router stop broadcast?

Well I was at work. And one of our customers connected a new device to that router. Additionally a switch was already connected to the router. So there was only the switch connected to the router, ...
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2answers
491 views

Can a broadcast storm do physical damage to computers and networking hardware?

We had a broadcast storm that went undiagnosed for several hours. After the problem switch was unplugged and traffic returned to normal, we had a handful of machines and switches that were broken. On ...
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1answer
6k views

When and where to use Spanning-Tree (Portfast)

The tl;dr, in which scenario (switch-to-host, or switch-to-switch) do I use spanning-tree portfast or spanning-tree ...? We had a catastrophic network outage today. My first question to my boss was "...
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1answer
81 views

Routing between network 1 and subnet of network 2 And their broadcast address

Suppose there's a network A with network 10.0.0.0 with network id=10.0.0.0 and Broadcast address 10.255.255.255 and Mask = 255.0.0.0 and network B with network 197.10.3.0 with network id =197.10.3.0 ...
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649 views

Can a large broadcast domain break accesspoints

I have a network with a large class B broadcast domain (172.16.0.0/18 - 172.16.192.0/18) with a single DHCP server. I have lots of L2 switches in this network but there is no VLAN configured. My ...
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2answers
3k views

Is there any difference between Limited Broadcasting and Directed Broadcasting when used in same network

I understand that limited broadcasting happens locally and can be done by using destination address as 255.255.255.255. The directed broadcasting happens across networks. To be precise, i want to ...
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1answer
776 views

Broadcast storm generation

Recently I managed to trigger storm control the university end-point I was using (they told me it triggers at 10% bandwidth broadcast traffic). The end-point had a switch plugged in, the switch had a ...
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1answer
597 views

How does broadcast work in cable networks?

Sorry for the long post. I tried to make it small but couldn't make it any smaller. Any help would be really appreciated. It would be great if you can explain from the basics. In the book "Computer ...
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1answer
631 views

Why does OSPF use flooding instead of broadcasting?

In flooding, we send unicast/multicast frames to all the routers in the network, whereas in broadcasting, we have a broadcast address by which we send packets to all the routers. In OSPF, "Router ...
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3answers
1k views

How to minimize broadcast-traffic in a multi-ap wireless network?

For example let's take a University's wireless network for the students or a Wifi in a Hotel: There are many wirelss devices that are causing broadcast traffic. In theory: Is there any way to ...
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1answer
69 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
234 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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107 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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1k 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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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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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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2answers
22k 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
898 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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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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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
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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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401 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
729 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
10k 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
648 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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555 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
4k 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
491 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
67 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
117 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
647 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
13k 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
313 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
3k 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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372 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
877 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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3answers
11k 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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605 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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4k 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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370 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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509 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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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
274 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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324 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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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 ...