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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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
324 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I'm reading a text (possibly outdated) and it states that large amounts of Layer 2 broadcast can degrade the performance of the workstations on the network - due to CPU interrupts.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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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 ...
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1answer
840 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
303 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
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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
567 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
187 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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3answers
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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
6k 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
180 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
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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
5k 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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5answers
59k 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 ...
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2answers
405 views

'Copying' UDP Broadcast to Specific IP Address?

I'm very inexperienced in networking, so please pardon any idiocy. We are mechanical engineers trying to connect weird hardware that talks on Ethernet. We have a device A that can only send UDP ...
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1answer
665 views

the difference in dealing of Layer 3 Switch and Router with broadcast communication

How does L3 Switch deal with broadcast communication such as ARP,DHCP or Broadcast storm? Is it the same that router deal with such as blocking a broadcast communication or ip address "255.255.255.255"...
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1answer
671 views

Why does a sever's host automatically broadcast an ARP request after a server attempts to reply to a BOOTP request?

I realise BOOTP is a legacy system, but this is for my reading for my studies. Consider a client, C, that is bootstrapping itself. It sends a BOOTP request to the server—obviously because it does not ...
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2answers
852 views

Arping for local broadcast address

Given the local IP-network 10.173.128.0/24 I am looking at a wireshark and there is an ARP for 10.173.128.255. Why would a network client ever ARP for a broadcast address? Does this indicate a ...
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1answer
262 views

broadcast packets snmp graph shape

I recently started using OpenNMS to monitor our LAN. I found this broadcast packets graph on several devices. I'm trying understand the consistency (shape) of these data. Most other graphs, for any ...
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1answer
127 views

Losing data when broadcasting over switch

I set up a port based VLAN on the first few ports of a 10GbE switch for broadcasting a UDP data stream. The data stream should use maybe 1/4 of that bandwidth. The switch is a netgear M7100. The ...
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2answers
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HP ProCurve Auto WOL MAC Address of offline devices

I'm attempting to build a system to Auto-WOL devices when plugged into HP ProCurve switches (2510G and 2530G models). This is on a completely flat network, no VLANs or subnet routing. If you'd like ...
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1answer
293 views

What does Round Trip Time / Transmission Time tell us?

To phrase it as it's phrased more commonly: What does RTT/T tell us? I've seen this formula - Transmission Efficiency - mentioned a lot when it comes to networks: β = RTT/T But what exactly does ...
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1answer
86 views

Valid broadcast and multicast addressing

The other day I ran across a piece of software configured to "multicast" using the address 255.5.6.7. While I've seen local broadcast (255.255.255.255) and "true" multicast (as defined in rfc5771), ...
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1answer
388 views

force client to send broadcast packet

I have WiFi mesh network with more than one AP. So I want to see the clients' RSSI level for each APs to steer them to AP with better RSSI. I am curious whether I can check the RSSI by forcing them to ...
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How does router prevent Broadcast radiation

I just learned networking and according to a wiki article on broadcast radiation prevention, it says: Filtering broadcasts by Layer 3 equipment, typically routers (and even switches that employ ...
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1answer
82 views

ARP request complexity squared?

Is it valid to say that the complexity of ARP requests in a broadcast domain increases squared to the number of participants, as in the worst case every participant wants to address every other ...
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1answer
397 views

Do you happen to know why this happened on my outside interface? (wrong subnet, proxy arp)

The OUTSIDE interface on my firewall appliance is assigned IP address .2 The router it's connected to (ISP) is .1 Keeping in mind Proxy ARP was turned on (don't recall doing that, but it was), I had ...
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1answer
15k views

RIP V2 multicasting looks as broadcasting at IP add 224.0.0.9

In RIPv1 the packets are broadcasted out all ports with dest. IP 255.255.255.255. In v2 they are multicasted with dest. IP 224.0.0.9. In Packet Tracer, this v2 packet is transmitted over all ...
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0answers
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Is it possible to calculate the path loss in an UMTS system if the current HNB CPICH power and RSCP values are known?

Please let me further elaborate on my question: Let's say we have an HNB with 2 Watts of power allocated for the common pilot channel. This would mean that the radiated signal power at the HNB site (...
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2answers
2k views

Cisco: Storm Control not filtering packets on trunking port

We have an unknown device causing broadcast storms on the network. I have applied storm control to ever single access port in the location, and yet the broadcast storm exists. I was wondering if I ...
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4answers
642 views

Calculating link utilization during a broadcast storm

Assume 3 switches connected in a ring topology forming a loop. If STP is disabled, a single broadcast packet is going to create a broadcast storm. If i assume a broadcast packet size to be 100bytes ...
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1answer
706 views

Identify gratuitous ARP

I want to identify a gratuitous ARP. Can I say: If sender IP address and target IP address equal, it's always a gratuitous ARP?
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4answers
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How does DHCP assign an IP address?

I understand that IP address is a unique address to identify a machine in a network. But for the first time when i Plug in say ethernet cable of a network to my PC's Ethernet Port, how the IP address ...
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3answers
32k views

How broadcasting works on different networks?

I was reading DHCP ( RFC 2131 ), I have basic knowledge about Relay Agent and Broadcasting. But for Understanding DHCP in depth, I felt like I have to know Broadcasting and Relay Agent ( RFC 1542 ) in ...
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1answer
17k views

How do VLANs affect the broadcast domain?

I'm repeating a "LAN Switching and Wireless" module in college and I'm looking over past exam papers in preparation for the repeat exam. One of the questions is What is a broadcast domain? Using an ...
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1answer
14k views

Difference between local broadcast and directed broadcast [duplicate]

In a Class E IP address , in the first octet,255 is reserved and used as a local broadcast.What does the term "local" signify here?How does it differ from a directed broadcast?
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1answer
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Why should one server repeatedly ARP for the same host?

I am trying to use Wireshark to find the root cause of a particularly slow network, and started by examining Broadcast traffic. Not only does Broadcast traffic represent over 25% of total traffic (at ...
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3answers
6k views

Wake on LAN across VLANs in IPv6 network

In IPv4, if I want to send a magic packet to a workstation in another VLAN, I enable directed broadcasts in the remote VLAN and send it to the VLAN's broadcast address. This works great. In IPv6, I ...
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2answers
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OSPF manual neighbor configuration requirement on NBMA network

Why are OSPF neighbors manually configured on NBMA networks even when you enabled it with the broadcast keyword in frame map statements? Example is NBMA point-to-multipoint access. Thanks.
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2answers
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Technical difference between a Collision and Broadcast Domain

Many people new to networking wonder what the technical differences between a broadcast domain and a collision domain are. Specifically: What criteria is used to know the boundaries of a collision ...
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2answers
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ARP Replies can they be Broadcast

I have been informed by certain networking professionals that ARP replies can and sometimes actually are broadcast packets instead of unicast. If and when would you use a broadcast ARP reply?
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1answer
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What is this UDP 5002 broadcast?

I hope this is an appropriate place to ask this. I'm confused because it's a broadcast at Layer 2 but it's UDP inside a VLAN with a destination to a unicast address (Y.Y.Y.Y). I was just wondering ...
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1answer
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Can a Bridge forward frames with the destination as broadcast/multicast

I have a question regarding multicast and broadcast frames on a network bridge. Will the bridge forward these frames from one network segment to another network segment ?

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