Questions tagged [multicast]

For questions about multicast communications and protocols.

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7
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3answers
3k views

OSPF and its use of Multicast

When it comes to OSPF and its use of multicast, am I correct in believing that IGMP forwarding and an IGMP querier is still required within the local segment? My understanding would be without this, ...
2
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1answer
34 views

In an IGMP V2 membership report message, isn't the destination Ethernet address based on the multicast group IP address?

Specifically, I think for this message type the Ethernet destination address always starts with 01:00:5E, followed by the second byte of the IP address masked with 0x7F, followed by the third and ...
4
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3answers
5k views

What is the difference between source based tree and shared cost-based tree?

In case of multicast routing, I encountered source based tree and shared cost based tree.What is the difference between source based tree and shared core based tree? In which case they are used? what ...
0
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1answer
23 views

Are there broadcast/collision domains on non-Ethernet networks?

What if we have routers or hosts connected via ATM, Frame Relay, or SONET; that is, what if we have IP over SONET, IP over ATM, IP over Frame Relay, etc., do we still have broadcast domains and ...
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0answers
17 views

Multicasting with Layer 3 Switches [duplicate]

I was wondering if someone could advise on this please - I want to set up multicasting on a network of layer 3 switches. So I understand I should enable ip igmp snooping on all the switches and then I ...
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2answers
50 views

MAC address and unicast, multicast and broadcast

I'm very new to computer networking and I'm trying to figure out this dilemma about the Unicast, Multicast and Broadcast transmissions. I was told that MAC address are unique for each device and they ...
12
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3answers
4k views

Why isn't multicasting more popular?

Multicasting seems provide an efficient method of routing networking traffic from a source to multiple end users, especially at this moment in time with teleconferencing, streaming media, online ...
0
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2answers
67 views

Why does IPv6 NS not use unicast address but multicast

This is a follow up of Why not put unicast address in IPv6 packet containing NDP neighbor solicitation instead of solicited-node multicast address? The accepted answer makes no sense. It states the ...
2
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0answers
73 views

IGMP Snooping issue. probably

I have multicast hosts that keep leaving a group, only to join back up which results in loss of video feeds. The network consists of a variety of Cisco 2960's and a Cisco 9300 w/ PIM Sparse mode set ...
0
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0answers
29 views

Issue with PIM-SSM Multicast Configuration ISR4431s

I have an issue with my PIM-SSM multicast configuration using ISR4431s.    I am wanting to forward broadcast data from an application from one VLAN in on the multicast source to another VLAN on a ...
2
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2answers
126 views

How to handle multicast address collisions?

Assume 2 multicast IP addresses IP1 and IP2 whose mac addresses are same due to collision Let's say a host's NIC has joined multicast stream IP1 and another host on the original host's subnet joined ...
1
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0answers
35 views

How should OSPF work over WiFi? [closed]

I've had problems running OSPF over my WiFi network, and it seems to be related to multicast. The routers can't maintain a neighbor relationship, and when I watch the packet traffic I see one router ...
0
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2answers
515 views

Private Public and Special IP addressing

Is the IP address 224.0.0.0 routable over the internet?
9
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2answers
524 views

How to control unwanted UDP traffic (Broadcast & Multicast) on Cisco Router 2911?

Please suggest, we are getting UDP traffic either broadcast or multicast in router 2911 which cause 95%+ utilisation of the router. And we got error in link and business impact due to this. Company ...
4
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4answers
11k views

Is multicast possible in tcp?

I got an assignment to implement unicast, multicast and broadcast in UDP or TCP in java, so I searched for it and I only got UDP implementation of multicast. My question is following: Is there ...
0
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1answer
80 views

How to enable Inter-VLAN multicast traffic on a layer 3 Siemens RX1510 Network Switch using IGMP?

I have a single Layer 3 Siemens RX1510 network switch split into 4 separate VLANs on different subsets. Name | Gateway | Subnet VLAN1 | 198.97.100.123 | 255.255.255.0 VLAN2 |...
0
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1answer
48 views

In PIM Sparse Mode, can the Rendezvous Point be the first or last hop router?

In tutorials and configuration examples, usually, the Rendezvous Point is described as the central registry to match multicast senders with receivers. FHRs and LHRs send PIM messages to the RP to be ...
0
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2answers
56 views

What's so special about the multicast address range?

I'm reading a little on IP multicast and have trouble understanding the significance of multicast address range (224.0.0.0 - 239.255.255.255). What makes this range significant? Why not multicast on ...
3
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0answers
2k views

Regarding vPC Dual Active or Split Brain scenario

Consider the below topology: Imagine that both the vPC peer keepalive link and vPC peer link have gone down. I am trying to understand how will that lead to unpredictable traffic flows or loops. ...
4
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4answers
380 views

Layering unicast addressing over multicasts

My question has to do with layering of unicast over multicast and has two parts. Part 1. IP unicast over MAC multicast First part of the question is whether there is a standard that prohibits use of ...
2
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2answers
209 views

How do hosts subscribe to multicast addresses?

So I am having a hard time finding materials online that explains how multicast address are set. I understand what unicast is: Basically one to one communication. In this scenario, an address ...
12
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0answers
629 views

PIM-SM with BSR over SSG5 VPN tunnel

I've created a lab to troubleshoot an issue I'm having with PIM-SM and BSR. There are two sites connected via two Juniper SSG5s (6.3.0r17) with just enough configuration to focus on the problem at ...
2
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1answer
72 views

How can MLDv2 work according to the RFCs 3810 and 4606?

When IPv6 Stateless Address Autoconfiguration is happening, an interface/node has to join the all-nodes multicast address and the solicited-node multicast address AFTER forming a "tentative" ...
3
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3answers
13k 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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0answers
12 views

Linux local multicast egress follows FORWARD chain when smcroute is active [closed]

Rather than a configuration issue, this is a "Is this expected behaviour" question. Given the following test box (Stock Ubuntu 18.04 LTS): +---------------------------------------+ | ...
0
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2answers
140 views

Unicast to Multicast possible?

could I check if it is possible to convert TCP traffic to UDP multicast and if there are any appliances / switches that can do so? E.g. Workstations A, B and C establishes a TCP connection with ...
2
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1answer
58 views

Interaction between multicast sources and first-hop routers (possibily DRs)

I might be missing the obvious but I would like to know how the first-hop routers are aware that multicast sources are sending multicast packets and such packets are eligible for the PIM-register ...
5
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1answer
115 views

IP pim sparse or dense mode

I have an IF/RF station that is receiving RF signals from satellites, then converted to IP to be encoded, decoded, multiplexed, and modulated again to RF so that it's sent to wireless and wired ...
1
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1answer
246 views

Can communication to broadcast 224.0.0.1 be made to reach hosts outside of the local subnet?

I been asked the question if it is possible for an a IP host to use multicast to address 224.0.0.1 in order to reach (and get a response from) another host which is not on the local network segment ...
2
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4answers
123 views

Why not put unicast address in IPv6 packet containing NDP neighbor solicitation instead of solicited-node multicast address?

This is a follow-up question to Why is the NDP Neighbor Solicitation message sent to the solicited-node address?. Summary: say I would send an IPv6 packet and put the unicast address of the host I ...
2
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3answers
276 views

Will pinging the multicast “all hosts” IP 224.0.0.1 fill my ARP cache with all hosts on my current subnet?

Just wondering in case I ever have a want / need to see all the hosts on my subnet.
4
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1answer
65 views

Function of the P-bit flag in an IPv6 multicast

Currently I'm trying to learn (common) things about IPv6 and started with the address format and the address scopes. Finally I reached the multicast part where my problem with the definiton of the ...
0
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1answer
420 views

Routing Multicast on a single L3 switch

I am currently testing how to route Multicast on a single L3 switch. I am currently testing 2 Vlans. I researched and I know I have to use PIM or Mrouter port for this scenario but that is for when ...
0
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1answer
138 views

Avoid bottleneck in UDP multicast

The question is that a server is serving a multicast group with UDP. Lets say that its a file server and it will be serving big files (~10GB). Now we have a multicast group with multiple clients. Some ...
0
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1answer
169 views

Multicast in one VLAN

I need to receive multicast traffic over L2 segment on my client machine. But for some reason I am unable to do it. To my understanding with such scheme I should receive traffic if inbetween Juniper ...
0
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1answer
74 views

Multicast in enterprise network

Once I have heard from a professional that multicast is forbidden (or not suggested or not allowed) in enterprise networks from 2014. (He referenced to a standard or recommendation document or ...
0
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1answer
54 views

Purpose of prune message in rpf

I read that when a multicast aware router without receivers received a multicast message, the router will send an upstream prune message. I don't understand what is the purpose of the prune message. I ...
2
votes
1answer
493 views

Setting Destination MAC address for RTP/UDP packets

I have a requirement where I have to send the UDP packet to a destination multicast IPv6 address. In addition to that the packets must also have corresponding destination multicast MAC address set. I ...
1
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1answer
252 views

Dell PowerConnect Firmware Update / Kemp VRRP

We just ran into the same problem outlined in this post: KEMP load balancers using UCARP (VRRP) - multicast MAC address not being picked up The only work-around that I was able to do was to disable ...
1
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0answers
122 views

To multicast or not to multicast over LTE? [closed]

I have an IOT device with static IP connected to a Mikrotik LTE device on ether1. The IOT host sends a multicast packet every second. The packet contains the IP and MAC of the host. IP-Multicast: ...
3
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2answers
3k views

IGMP and multicast forwarding

So my question is, will using IGMP alone(without IGMP snooping, PIM...etc) making router forwarding multicast traffic? I'm working on a buggy switch, but I don't know about networking too, so I'm ...
2
votes
1answer
127 views

Defining what type of casting based on IPv4 address

I'm kinda new to networking. I have a small question, how can I determine what type of casting (unicast, multicast or broadcast) is it based on IPv4 address. For example: 142.55.172.200 I tried to ...
7
votes
1answer
8k views

Mitigating a IPv6 malformed packet multicast flood

So we just had our first IPv6 multicast flood in the network this morning. We managed to stop the offending computer by blocking the mac address with: mac-address-table static x.x.x vlan x drop ...
1
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1answer
672 views

Cisco 49XX multicast flooding

I have problem with multicast on cisco 4948. I've got vlan 9 with muilticast, which configured on several ports. Switch floods multicast traffic on all ports configured with vlan 9. It consumes link ...
1
vote
1answer
60 views

What practical concerns led to the use of multicast?

Answers to a question on SF explain the differences between broadcast and multicast. It is not clear yet for me which practical concerns brought in the usage of multicast. My understanding is that, ...
2
votes
2answers
162 views

Broadcasts in IPv6

I'm aware of the fact that broadcast has been removed from IPv6 and just has multicast instead. However, recently I read "This process (ARP) is now achieved via a multicast address called the ...
7
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2answers
132 views

VLAN clarification

I've inherited a network with approximately 200 computers and no VLANs configured. We are currently adding a system that uses multicasting to communicate with each other and will be adding VoIP in 2 ...
3
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2answers
640 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 ...
2
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2answers
6k views

Multicast between VLANs

I've following scenario Upper computer on VLAN 10 is sending some multicast messages and lower computer on VLAN 10 sends IGMP join periodically. Lets say MC address is 224.1.1.1 Now, computer on ...
1
vote
2answers
1k views

Does a multicast source have to be connected to the RP for Cisco PIM-SM to work?

I'm fairly new to networking in general, but I need to develop a 4 point mesh with redundant paths routing multicast from point A to points B and C. I've already setup the mesh and have network ...