Questions tagged [multicast]
Multicast is the mechanism using which data traffic is reduced thoughout the network if a certain number of receivers are interested in the same data from the same source. This increases the efficiency of the network as less packets needs to be processed by the intermediate routers in the network. An inverted(spanning)tree like traffic path is formed for multicast data. This ensures that packets are replicated only when necessary.
118
questions
14
votes
7
answers
67k
views
Linux built-in or open source program to join multicast group?
I'm using tcpdump to capture multicast packets and had to code up a custom program to join multicast feeds so tcpdump will "see" the packets. Just wondering if netcat or any other applications can ...
- 353
13
votes
4
answers
4k
views
Can YouTube (e.g.) send a video file once and multiple users stream it?
Can YouTube (e.g.) send a video file once and multiple users stream it? Or does YouTube need to send the file to each person individually, even though all of the users live in the same region?
If it ...
- 157
11
votes
3
answers
21k
views
IPv6 multicast address for all nodes on network
I've got a basic network with 3 nodes (VM's).
One node publishes an event, the other nodes listen for it and print something when received. It used to work one-on-one (so node gives event to each ...
- 305
11
votes
2
answers
12k
views
Getting Chromecast to work across subnets
I know Google says its not supported.
Has anyone got a Chromecast to talk to a client on a different subnet?
I have an OpenWRT router connected to my internet providers router (parent router).
The ...
- 221
8
votes
1
answer
17k
views
WiFi UDP unicast vs. multicast speed
From what I have gathered UDP multicast / broadcast over WiFi will not yield the speed as one would have thought. What about UDP unicast over WiFi? Can anyone confirm that the latter will have a ...
- 499
8
votes
1
answer
3k
views
Why does router send packets to the multicast address?
I have a computer running linux and it has ufw activated with a couple of simple rules set. It is connected to ASUS 4G-N12 router by wifi. When I looked in ufw logs a few days ago it turned out that ...
- 91
6
votes
3
answers
40k
views
How do I disable multicast on the TCP/IP stack for Windows?
I'd like to disable the TCP/IP stack's support for multicast completely on Windows for diagnostic purposes. How do I do this?
I'm looking to do this on Windows XP, but if none can be provided, ...
- 556
5
votes
2
answers
21k
views
How do I check if my router blocks multicast traffic?
I am trying a sender and receiver multicast c# program on my computer. How do I check if my router blocks multicasting? i.e whether members of the group receive packets from 224.0.0.1.
- 730
5
votes
1
answer
26k
views
Filtering TCPDUMP over packet length
I am looking to narrow down my tcpdump by packet length. I know I can `| grep but I was wondering if I can pass this particular packet length as an option in 'tcpdump'. I am trying to write a script ...
- 431
5
votes
1
answer
2k
views
IGMP and Wake On Lan
I have a Windows 10 server which has been operating well for some time using Wake On Lan. The Realtek adapter is set with Wake On Magic Packet enabled and Wake On Pattern Match disabled. Similarly, ...
- 121
4
votes
5
answers
19k
views
How do I enable/set multicast rules using firewalld in RHEL7 / CentOS 7
I cannot find docs on how to enable multicast for firewalld which is the default firewall in RHEL / CentOS 7. Can some enlighten me? FYI: I know how to do it using iptables.
- 141
4
votes
1
answer
38k
views
How to connect two bluetooth speakers simultaneously via "Virtual Audio Cable"?
I have two speakers that I need to connect wirelessly via bluetooth. These are standard aux/usb speakers, and presently I've connected one of the speakers via 3.5mm jack to my windows 10 laptop. I ...
- 1,795
4
votes
2
answers
8k
views
DD-WRT and Chromecast: default WLAN to LAN bridge blocks UDP?
I have DD-WRT running in gateway mode on a DIR-615 I1. I've updated to the newest available build.
Chromecast is a wireless-only device, for those unfamiliar. The device has been set up and ...
- 41
3
votes
1
answer
4k
views
Windows route selection and "route print -6" vs "netsh interface ipv6 show route"
So I'm using Windows 10 and I need to redirect some IPv6 multicast traffic to a specific interface (a USB-Ethernet adapter to be more specific).
By default all multicast traffic is going to my WiFi ...
- 133
3
votes
2
answers
5k
views
Record multicast stream on multi-homed Linux host
I have what sounds like the simplest possible use case, and yet nothing is satisfactory.
I have a multi-homed host and I would like to listen to multicasts on eth1, and shove all the payload (NOT ...
- 343
3
votes
1
answer
13k
views
iperf returning “bind failed: cannot assign requested address” in Windows XP and 7
I am trying to set up iperf on an old HP server running Windows XP Professional to test multicast, but whenever I issue the command iperf -s -u -B <ip address>, it returns:
bind failed: ...
- 197
3
votes
2
answers
16k
views
How can I test if my Windows XP machine can send multicast packets?
I would like to know how test if my Windows XP machine has the ability to multicast. Therefore, I want to multicast a packet from my machine to itself.
How can I do that?
- 175
3
votes
1
answer
6k
views
VLC internet multicast
I want to stream video using VLC so everyone can connect to my pc and watch it. Is there any way to do it? As I understand I can multicast video only in my network (but I need it to be available from ...
- 133
3
votes
0
answers
4k
views
List which applications are subscribing to a multicast group in Windows
I've been looking for way to list what processes/applications on my host are subscribing to what multicast addresses.
Through the command line, I can issue
netsh interface ip show joins
which lists ...
- 143
2
votes
6
answers
255
views
Software to assist with a training environment [closed]
We are currently in the process of building a training room where we will bring clients to train them in the use of our software.
The basics are that an instructor will provide training on how the ...
- 4,244
2
votes
2
answers
28k
views
How To Set Multicast Rate On Apple AirPort Extreme
I have an Apple AirPort Extreme Rev C (2011) and I need to set a manual multicast rate. While I can set a manual multicast rate, I only have the option between low, medium and high.
In the previous ...
- 255
2
votes
1
answer
3k
views
Multicast streaming without IGMP
If server is streaming to multicast address (for example 224.1.1.1:1234) and a client is receiving data from the same address: in this case, is IGMP protocol used automatically? Is it possible to use ...
- 144
2
votes
1
answer
13k
views
How to get a stream with ffmpeg through a specific eth(interface)
I have a server with 2 interfaces, eth0 and eth1.
eth0 -> conected to Managment Switch
eth1 -> conectated to Video Switch
I would like to get a multicast with ffmpeg through eth1.
Is there some ...
- 21
2
votes
1
answer
376
views
Multicast configuration for mDNS
I just bought a pair of Nexuslink 2000PT powerline adapters. These are identical to the Comtrend PG-9182PT.
It turns out that my Chromecast's mDNS broadcasts are unable to make it through the ...
- 68
2
votes
1
answer
279
views
Testing multicast - not getting proper results
This question was asked before here:
https://networkengineering.stackexchange.com/questions/71813/testing-multicast-problem
But I was pointed here.
I use this tool: https://www....
- 184
2
votes
1
answer
3k
views
NTP Multicast configuration
I'm trying to get NTP multicast set up between a few computers. Right now I'm getting NTP multicast packets from a computer that I have neither access to nor information on (let's call that A) that is ...
- 21
2
votes
0
answers
29
views
ffmpeg - mpegts Multicast
I'm generating a multicast stream with this command:
ffmpeg -hwaccel_device 1 -format_code Hi50 -re -f decklink -i 'DeckLink Duo (1)' -pix_fmt yuv420p -c:v h264_nvenc -profile:v high -b:v 3500k -rc 2 -...
2
votes
1
answer
661
views
Tunneling multicast over SSH
There's a remote server which has a LAN interface configured with IP address 192.168.100.2 as well it has a routing rule enabling all multicast 224.0.0.0/4 -> 192.168.100.2.
The remote server is ...
2
votes
2
answers
3k
views
What is this UDP traffic to 230.0.0.1? And how can I block it?
My VM is of IP 192.168.3.20 in the network of 192.168.3.0/24. While running iptraf command on my machine, I am getting the response as shown in the attached image.
I can't understand what kind of ...
2
votes
0
answers
414
views
ffmpeg restreaming with an intermittent input
I have a live unicast stream that I restream as multicast. This works fine:
ffmpeg -i <uri> -c:v copy -an -f rtp rtp://<multicast_ip>:<port>
However, on occasion the input stream ...
- 121
2
votes
0
answers
800
views
VLC - Video Streaming Synchronization
Using VLC 2.2.4 Weatherwax.
I'm streaming a video using UDP as multicast. Stream is displayed by 2 different clients using VLC.
I'm trying to synchronize the display on these 2 clients.
I've seen ...
- 21
2
votes
0
answers
6k
views
Why does multicast streaming only work with 224.0.0.0/4 routed to network card/NIC in Linux?
a project of mine involves multicast streaming of DBV-S2 TV channels by using a networked SAT tuner. As there are no IGMP-capable network switches, the network is quite stressed and so I set up a ...
- 159
2
votes
0
answers
298
views
Swapping the ISP supplied router on DSL connections that also supply TV
My ISP is TalkTalk and I have one of their FTTC packages. With that I also have their YouView TV service. Before getting this service I used my own routers, as ISP supplied ones didn't have the ...
- 234
2
votes
2
answers
565
views
Weird connectivity issue wtih USB Wifi stick
I'm setting up two PCs, and I've been having massive troubles getting a USB wireless dongle working. I have two Sony VAIOs (Windows XP, SP2) that I found second-hand, and since they will be in a ...
- 173
2
votes
1
answer
1k
views
Checking if my ISP supports IP multicast [closed]
I want to cast a live stream and can't tell if my ISP will support multicast or not.
How do I check whether my ISP supports IP multicast?
- 335
1
vote
1
answer
1k
views
Multicast LAN ping twice as slow than unicast?
I've done a simple test on my little home LAN.
I have enabled broadcast ICMP echo responses with
sysctl net.ipv4.icmp_echo_ignore_broadcasts=0
on just a single host and then pinged a multicast ...
- 2,956
1
vote
1
answer
238
views
Do you have to join the broadcast group for IPv6 multicast?
When a client joins a network, is the client included in the ff02::1 IPv6 multicast group, which "broadcasts" to all nodes on the segment. OR, do I have to subscribe to the group using ...
1
vote
1
answer
3k
views
Multicast traffic generator for Windows
Are there any multicast traffic generators for Windows?
1
vote
2
answers
179
views
IPv6 SSM multicast: is it built in or do you have to use another protocol like PIM-SM with it?
I'm trying to understand how integrated SSM multicast is to IPv6. Is it built in and sent solely by ICMPv6 messages or do you have to run something extra like PIM-SM? The reason I as is I've seen ...
- 151
1
vote
1
answer
491
views
Need clarification about ipv6 multicast and ipv4 broadcast
I’m studying IPv6 and I’m traying to better understand how it works in deep.
So far, I know that there are essentially three types of addresses, based on the type of communication:
unicast: one to ...
- 103
1
vote
1
answer
3k
views
What hosts does multicast DNS send to?
mDNS (multicast DNS) queries are sent to 224.0.0.251:5353. While this is a multicast address, don't all hosts on the network segment have to receive this traffic in order to have the correct DNS ...
1
vote
3
answers
670
views
How far does a multicast message go?
I'm wondering how far a multicast message sent from a server can go.
What stops it from going to all computers in the world?
- 34.5k
1
vote
1
answer
304
views
Linux conntrack not seeing multicast responses as part of the same flow
My tv (192.168.1.48) is multicasting an SSDP packet (to 239.255.255.250:1900), and on my server (192.168.1.17), by running smcroute and doing some packet mangling to increase the IP TTL of this ...
- 240
1
vote
1
answer
495
views
Source of multicast broadcast to WAN port
I have noticed multicast broadcasts from 192.168.30.2 hitting my router's WAN interface. That would be sourced from an interface that's somewhere locally on my router, right, or where would it be ...
- 21
1
vote
1
answer
2k
views
Can Multicast cause network loops?
I've been dealing with a persistent network loop for the past month, trying different things. Now I see in one of my network interfaces that it recorded 1.6 million multicasts, and roughly half a ...
- 11
1
vote
1
answer
4k
views
Limit UDP outbound traffic to loopback (localhost) instead of eth0
Atm i'm testing it on Ubuntu Server at VMware Workstation + Windows 7 local host with bridged connection. Later this has to go to live server.
I have VLC streaming video file on Ubuntu with
cvlc -...
- 73
1
vote
2
answers
337
views
What could be the cause of multicast on Ports 3289, 22222 and 10004?
I've recently been monitoring my home network traffic heavily (using Netflow).
Today I noticed some odd multicast coming from a Windows 11 laptop (it was left on, but unattended). I have AVG and ...
1
vote
0
answers
229
views
beacon interval, DTIM interval, & their effect on the network throughput/latency?
what effect does having beacon interval, DTIM interval set to a higher or lower value have on a wireless network latency? if I understand correctly if a network only has one AP, then setting the ...
- 11
1
vote
1
answer
152
views
Encoding multiple live channels
I have a code working that encodes a UDP live channel into an HLS stream using m3u8 container. My question is, is there a way to simplify doing multiple channels, and ensure each is the same quality ...
- 11
1
vote
1
answer
602
views
iperf multicast server cannot start - "bind failed: Cannot assign requested address"
I've seen this question asked on here but the user was using Windows XP and Windows 7, and none of the answers I saw worked for me. I'm trying to set up a multicast server on Windows 10, and I ...
- 11