Questions tagged [multicast]

For questions about multicast communications and protocols.

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965 views

Any ideas why Cisco 3560G switch isn't passing broadcasted Ethernet packets?

I have a 24 port Cisco 3560G switch that I'm using to try and pass broadcasted Ethernet packets. I have a computer plugged into one port, and a IEC-61850 GOOSE publisher plugged into another port. ...
3
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1answer
2k views

overcome microbursts in cisco router or transmitting linux machine

I have linux machine multicasting UDP streams with Java applications. The multicats go though ciso router. I see lot of packet losses at receivers. Checking ports in routers reveals overruns counter ...
3
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1answer
1k views

Network flooded with ICMPv6 Multicast Listener Report Packets

I recently noticed that 3 out of 4 Unifi APs kept reaching 100% CPU usage. When I jumped onto the networks and took a Wireshark capture I noticed 1000s of these packets being sent in just a matter of ...
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2answers
389 views

How do you disable IGMP-snooping on virtual nic macvtap

Networking community, Question: How do you disable IGMP-snooping on virtual nic macvtap? Background: We have noticed that Juniper vSRX 15.1X49-D60 (Running on Ubuntu 16.04LTS Server KVM) is ...
3
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1answer
1k views

Can we do destination port filtering in IGMP V2 or V3?

Is it possible to get a traffic from a multicast address with specific destination port using IGMP? For example, I have some multicast flows like 239.192.7.1:5000, 239.192.7.1:5001 to 239.192.7.1:5009....
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 ...
3
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2answers
1k views

Quagga (Zebra) multiprotocol BGP configuration for IP multicast routing

Host A: Eth1 = Multicast incoming from upstream provider OpenVPN_interface_point_A = point to point interface with point B ASN = 100 Host B: OpenVPN_interface_point_B = point to point interface ...
3
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1answer
1k views

Using IGMP but Multicast still Flooding

Im new here. I want to ask about the multicast, The first case is, I have switch HP 2530 24 port with 24 10/100 and 2 100/1000 NIC, And i have servers with bandwidth video multicast around 120-...
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3answers
6k views

How do I forward multicast packets over IPSec VPN Tunnel on Juniper SRX?

I have an IPSec site-to-site VPN setup between two SRX300 devices. I am trying to get multicast to travel across. I am looking for the simplest configuration possible to get this setup. I have found ...
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1answer
7k views

config pimd on Linux to forward incoming multicast packet to OpenVPN tunnel interface

Does anyone know how could I setup pimd on Linux so that multicast address from 225.0.30.30 could route to 172.24.0.66/30 router on the right? So this is the lab I just setup today, In the lab ...
3
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1answer
442 views

Multicast over Unicast IPv4 Routing

I have a little question and I did not find any direct answer on the WWW. So maybe someone else in this forum has the answer. I have two Cisco 2960X switches running in a stack with the sdm prefer ...
3
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1answer
603 views

PIM : How does a client discover multicast streams

I have a doubt about multicast. Topology diagram Multicast SEVER -- R1 -- R2 -- R3 -- PC1 From Above diagram , suppose PIM-SM is enabled on all the Routers and let us assume that R2 will be the RP. ...
3
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1answer
1k views

Private vLAN useful to isolate multicast sources?

On a Cisco 3750G switch I have a number (30-ish) of video processors in a vLAN providing multicast streams to clients via a router. Because all of the machines are in the same vLAN they see each ...
3
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1answer
437 views

Any router will automatically join at least two multicast groups on each interface. How do I see that on a Cisco router?

Any router will automatically join at least two multicast groups on each interface. How do I see that on a Cisco router? I know that they all join these two groups: all multicast nodes and all ...
3
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1answer
1k views

multicast not working in two segment network

I have two network segments connected to a single Cisco router by Cisco switches. I've enabled multicast routing on the router by running following commands: ip multicast-routing in configuration ...
3
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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
1k views

If I UDP multicast to 10 listeners in a multicast group, will my upload bandwidth usage increase by 10 fold?

My internet has an upload limit of 1 Mb/s. If I am in a UDP multicast group with 10 people and I send something to the group at a rate of .1 Mb/s, will my upload rate be 0.1 Mb/s or 1.0 Mb/s? Assume ...
3
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0answers
322 views

STB generate IGMP Leave without reason

In my network STB generates IGMP Leave (in STB logs "End of Stream") without any reason or there is something what I don't understand. There is one exeption STB directly connected to PIM (ASR920) ...
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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. ...
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0answers
1k views

How do switches behave on multicast? [closed]

I am benchmarking multicast throughput of my LAN using an application that considers all the servers as group members. The network consists of homogeneous servers (S0-S9: 192.168.21.70-79) inter-...
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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 ...
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2answers
600 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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4answers
97 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
227 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.
2
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1answer
662 views

Is it possible to set up (geographic) anycast on the Internet?

The top level DNS-servers use geographic anycast. Is it possible to set up geographic anycast on your own (DNS) servers on the Internet? The top level DNS-servers use geographic anycast. Is this set ...
2
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2answers
125 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 ...
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3answers
2k views

Why is a hash used instead of a simple compare for filtering multicast frames?

From the book Unix Network Programming, The frame is received by the datalink on the right based on what we call imperfect filtering, which is done by the interface using the Ethernet ...
2
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1answer
395 views

Is it possible to use 802.11n to send multicast?

I have tried to set the wifi multicast rates and find that all the multicast packets are send by 80211g, so that the max rate is 54M. Can I use the 80211n to achieve higher rate?
2
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2answers
257 views

redundant vpn to remote location with redundant links

I have this situation: Remote location with 6 devices collecting data and each connected to two VPN routers. Bonding is set up for those computers and data is sent to multicast address. Each VPN ...
2
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3answers
782 views

Translate between multicast addresses

I have an application with a bug that does not recognize a certain multicast address as valid. It's an address used by another system i don't have control over, and these two systems communicate via ...
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1answer
1k views

IGMP snooping across VLANs

Set up: Core switch: C1 C1 is an L3 switch--there is no router Access switches: A1, A2, A3 VLANs: V1, V2 Hosts: H11, H12, H13, H21, H22, etc. Connections: C1 connects to A1, A2, A3 A1, A2, A3 each ...
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1answer
5k views

Which VPN Types/Protocols inherently support Multicast Traffic?

At my work, we build mobile networks from scratch for customers regularly. (Mobile Networks: think battery powered LTE router with wifi.) Since we build from scratch we can be vendor agnostic and ...
2
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2answers
91 views

How to design a wireless network for efficient multicast or broadcast communications?

First, a little bit of background information: I'm working on some custom software that allows a group of computers on the same LAN to co-operate on a real-time task in a distributed, fault-tolerant ...
2
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2answers
184 views

Using as many multicast groups as transmitting devices

We have a set of ~40 embedded devices, each one equipped with a wifi module. All the devices are connected to the same wireless network. All the devices send packets to the same "master" computer. ...
2
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1answer
126 views

Query router for list of multicast sources [closed]

Is it possible to query a router to return a list multicast sources it has registered, via a protocol? For example, I want to know what multicast sources are available on a router but I don't have ...
2
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1answer
63 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" ...
2
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1answer
90 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 ...
2
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2answers
48 views

Can Multicasting be duplicated by broadcasting on a subnet?

Is there any functional difference between: A) Broadcasting to a range of addresses B) Putting the range of addresses into a subnet and broadcasting to that subnet Would it matter if there was a ...
2
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2answers
257 views

Are there limits to the number of global IPv6 multicast addresses in use at a time?

The address space for IPv6 multicast addresses is very large (something like 2^112) and so I'm imagining it might not be so hard to get my hands on a million or so of them at some point, and try using ...
2
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2answers
156 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 ...
2
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1answer
330 views

Why is only 24 bits of the MAC address used for multicasting?

When doing neighbor discovery in IPv6, the last 24 bits of the hosts MAC address is glued on to some link local multicast prefix. I'm wondering why 24 bits? Why not 48, or 32, or 16? What happens if ...
2
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2answers
3k views

TCPDUMP Output analysis

I'm running the following command on my backbone to monitor multicast traffic. I'm new to tcpdump usage and looking for some help: sudo tcpdump -i eth1 -n -p multicast I see a output like this - ...
2
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1answer
54 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 ...
2
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2answers
196 views

Cisco: multicast unregistred forwarding on ME3400EG-2CS-A access switch

I am connected to the Internet through an Cisco ME3400EG-2CS-A access switch, routing enabled. Gi0/1 and Gi0/2 are configured as a SVI (VLAN1) and on that ports I attached two pfSense firewalls with ...
2
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1answer
50 views

Should igmp table lookup misses flood to all ports?

With igmp snooping, upon receiving a multicast packet it looks up the table and decides which ports to forward the packet. What I'm wondering is, if there is not an entry in the table for that ...
2
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1answer
521 views

Rationale for EXCLUDE mode in mutlicast IGMPv3 / MLDv2

Both IGMPv3 and MLDv2 have an include and an exclude mode, where a multicast listener can specify to either listen only for packets from some list of source addresses (include) or only for packets ...
2
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1answer
600 views

Unable to route multicast from IPcam (four vlans, one switch, one router with router-on-a-stick)

Okay, so I've been searching far and wide for a solution to my problem here. I want to be able to access an IPcam through its respective software across VLANs. Hardware: Cisco 1841 Router, firmware ...
2
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1answer
465 views

Understanding multicast destination mac addresses

I'm currently learning about how to convert between a multicast ip address and the destination mac address. I fully understand the terminology, how to do the conversion, and why the 23 bits, instead ...
2
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2answers
846 views

Is a VLAN relevant for multicast frames?

In a switched Ethernet network is there a use-case for having VLAN tags for frames that have a multicast MAC as destination address? I cannot find a use-case because: VLANs are generally used for ...
2
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1answer
135 views

what happens to multicast outside of the RP domain in PIM-SM?

Imagine you have a ring of routers, all of which are routing multicast with PIM Sparse mode, pretend there's a single Rendevouz Point (RP) "Router A" for any multicast on 239.10.10.0/24. If a stream ...