Questions tagged [multicast]
For questions about multicast communications and protocols.
237
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Should (IPv6) multicast subscribers send report to query?
I am waking through RFC3810 and playing with MLDv2.
From that RFC I thought when anyone send query for group :: (all groups) and send it to address ff02::1 all subscribers on segment should send its ...
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54
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How to forward UDP unicast messages to multiple destinations [closed]
I am trying to forward a UDP Unicast message so that it cant be received by multiple computers. Can anyone point me in the right direction for how to accomplish this?
Here are the details:
There are ...
- 111
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81
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High latency - dense-sparse mode PIM
Colleagues, good day!
In my prod, I notice large delays to some switches behind which there are hosts with multicast reception
I wanted to know if my multicast is set up correctly, is it normal that ...
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0
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82
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Nonsense RFC 4604 forbids IGMP General Queries in SSM range but IGMP General Queries have no range and are send to 224.0.0.1, the all-systems address?
RFC 4604 Using Internet Group Management Protocol Version 3 (IGMPv3) and Multicast Listener Discovery Protocol Version 2 (MLDv2) for Source-Specific Multicast:
2.2.3. IGMPv1 Queries, IGMPv2 and MLDv1 ...
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53
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Can ELI/AAI/SAI addresses be Multicast?
In a slideshow by IEEE regarding the Structured Local Address Plan (SLAP), I saw the following table:
SLAP local identifier
SLAP Quadrant
Z bit
Y bit
X bit
M bit
second hex digit
ELI
01
1
0
1
0
A
...
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33
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Should a multicast router punt the multicast packets in addition to routing those packets if the router has an interface in this multicast group?
If the multicast router has the (S,G) route present and the same destination address G is also set on one of the router interfaces, then should the router send the packets addressed to group address G ...
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51
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Why does a PIM DM assert loser reply with a prune?
In PIM Dense Mode, why does an Assert loser send a Prune message to the winner? What is the actual motivation for this?
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What are the triggers for PIM-DM prune and assert messages?
There are articles explaining the PIM-DM mechanics, and they only confused me. Considering the most common topology, that of three routers, connected to each other like a triangle as such:
R1 -- R2
\ ...
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2
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54
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What ways are there to make sure router multicast tables are up to date?
I've been reading on IGMP v3 and think I understand the basics of how to join a multicast group - sending a Membership Report Message.
But I'm not sure what the "best" or even conventional (...
- 115
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21
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PIM-DM forwarding state expiry timer
I've recently read rfc 3973 - PIM-DM and there are a lot of timers explained but I couldn't find any information on the forwarding state expiry timer.
(172.45.1.15, 239.1.1.11), 00:00:06/**00:02:53**, ...
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49
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How does a PIM router know which neighbour is the upstream router?
I understand that certain PIM messages such as Join/Prune and Graft have a field called 'Upstream Neighbour Address' used to indicate the recipient of the message, which is the upstream router for a ...
- 183
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22
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In multicast, do shared trees exist solely to reduce router processing of (S,G) forwarding states?
I am asking this question strictly at a conceptual level. I am not asking from a specific protocol's standpoint.
Why do shared trees exist in multicast routing? What was the reasoning behind them?
...
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35
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Is there an IGMPv1 querier router after all?
I recently looked into the mechanics of IGMPv1 and v2. Reading RFC 1112, I understand that in IGMPv1, the Querier Router functionality does not exist. All IGMP configured routers in a local network ...
- 183
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2
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420
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What does 'moving packets away from the source' in RPF means?
I recently started studying multicast and I am a bit confused by how reverse path forwarding is explained.
Most of the sources describe RPF as 'moving packets away from the source' but I understand ...
- 183
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40
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ipsrc multicast group
I'm looking at some traces where a TTL exceeded in transit ICMP message with ipsrc as mcast is captured. The ICMP message is referencing the original ip header with a correct structure [ipsrc ucast, ...
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239
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Multicast destination address and port translation (NAT/PAT)
I have a requirement to translate multicast traffic destination address and port number. I see that Cisco has a feature called Multicast service reflection which translates the IP address, but it does ...
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1
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93
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IPv6-over-IEEE802.15.4 Multicast scope
An IPv6 Multicast address is defined as
| 8 | 4 | 4 | 112 bits |
+--------+----+----+-------------------------------------+
|11111111|flgs|scop| group ID ...
0
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81
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When using multicast, all users have same bandwidth?
I'm reading https://ieeexplore.ieee.org/abstract/document/9370130 and in this paper, achievable rate for the uplink transmission from user n to the UAV is
w_n is the bandwidth allocated to user n(...
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3
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1
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85
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Two multicasts from same source not reaching a destination
I have a single multicast source (Server A) sending to destinations 239.0.0.226 and 239.0.0.227, the source being directly connected to Switch A on VLAN 100.
Switch A is sending dozens of multicasts ...
- 165
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2
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734
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UDP supports multicasting and broadcasting in transport layer or application layer?
We know that UDP does supports multicasting and broadcasting. My question is which layer "UDP supports multicasting and broadcasting"? Is it transport layer or application layer? We know ...
- 378
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1
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156
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Ospf multicasting with two different group
Suppose I have one ospf network where two multicast group exists. And some routers is ospf which belongs to one group or multiple group (Like: routers E, H) and router is layer3 router (Like: ...
- 378
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81
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How do I set up IPv6 multicast over an MPLS carrier?
I'm setting up an MPLS carrier with VPNs in GNS3, using Cisco 7200 routers.
Exact version I'm using is C7200-ADVIPSERVICESK9-M Version 15.2(4)S5, but I'm willing to upgrade/change if that's needed.
On ...
- 121
3
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571
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IPv6 neighbour discovery blocked by MLD snooping switch
I recently noticed that my IPv6 multicast traffic was being broadcasted to all hosts connected to a switch, even those that had not subscribed to the traffic.
To fix this, I enabled MLD snooping on ...
- 341
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1
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551
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If a switch doesn't support multicast, are multicast packets simply flooded out all ports?
If a switch doesn't support multicast, are multicast packets simply flooded out all ports? This would allow multicast enabled hosts to at least still receive the multicast frames.
Follow up question. ...
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271
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broadcast instead of multicast for CARP/VRRP/keepalive
In many cloud environments, multicast is blocked therefore when trying to configure CARP/VRRP customer needs to add a dedicated switch.
For example, CARP partially works if using a vSwitch from Hetzer,...
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2
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3
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606
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Why does OSPF use flooding despite using multicast?
We know that flooding is only possible in layer2 switch. But in OSPF router in layer3 uses flooding with multicasting. Suppose we have one router in OSPF uses multicast address 225.0.0.9. If router ...
- 378
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2
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448
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Class D network for multicasting between group
We know Multicasting is defined as a single source sending to multiple recipients on a network when the receiver broadcasts a signal for acceptance. Multicasting has its own Class D IP addressing ...
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362
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IGMP in multiple switches with multiple Senders and Receivers in same VLAN
I am trying to send multicast traffic from 3 Senders to corresponding Receivers in same VLAN (100) spread across 3 switches.
I setup a Querier in one of the switch, but it doesn't seem to forward ...
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0
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112
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No entry in the multicast RIB while PIM join is present
I have a router which receives multicast traffic from the source over a multicast LSP(signaled by LDP):
root@PE3> show pim join detail
Instance: PIM.master Family: INET
R = ...
- 1,217
0
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130
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Juniper vMX router silently drops SSM traffic
I have a Juniper vMX router with two interfaces: ge-0/0/0.0 facing the multicast sender and ge-0/0/2.0 facing the multicast receiver. The router receives multicast packets addressed to 232.1.1.1 on ...
- 1,217
2
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2
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492
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Query regarding IGMP Querier Election Process
I wanted to understand how a querier election takes place.
Say we have to L3 devices with ip address 10.1.1.2 and 10.1.1.1.
PIM is not enabled anywhere.
I checked around and found that the flow would ...
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88
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How Pruning avoids loops in Protocol Independent Mulitcast (PIM- SM)?
I can not think of a scenario, how pruning avoid loops in PIM-SM when a router joins a SPT. I understood that it avoids duplicate messages, but how it avoids loops?
I want a scenario where the router ...
- 113
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1
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1k
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Forward Avahi mDNS packets from one network to another [closed]
I have a Linux device connected to two different networks. eth0 is connected to 198.18.248.x and wlan0 is connected to 198.19.255.x. Another device connected to the 198.18.248.x network and it's ...
- 111
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3
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250
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PIM Packet and NAT
Is it possible to NAT PIM Join packet?
Assume the receiver and the source are in two different networks (address regimes). Thus NAT is required. The upstream source and the groupe are included in the ...
- 107
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1
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153
views
What are the benefits of using MP-BGP multicast address family, under the context of inter PIM domains multicasting?
Under the context of inter PIM domains multicasting, 1 RP on each PIM domain (2 domains), attached with eBGP, with MSDP peering to exchange the actives sources, what are the benefits of using the MB-...
- 1,085
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103
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static IP multicast routing with IPSEC
for a specific application, I need to route a multicast flow with IPSEC (we use a CISCO ASA 5508 firewall), I am not a network expert then I will try to explain as best as I can our issue
I don't need ...
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78
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Does multicast over tunnels (e.g., GRE) require IGMP/MLD?
When subscribing to a multicast group on a tunnel device such as a GRE tunnel, are you supposed to participate in IGMP/MLD over that tunnel in order to announce your membership in the multicast group? ...
- 327
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1
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1k
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How to Stream from VLC using Multicast? [closed]
I have the following topology:
With the following router configurations:
R1:
hostname R1
!
boot-start-marker
boot-end-marker
!
!
!
no aaa new-model
no ip icmp rate-limit unreachable
!
!
!
!
!
!
no ip ...
1
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0
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351
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Multicast traffic through Cisco3850
I have a test scenario and trying to pass multicast traffic through Cisco 3850 according to the following diagram:
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210
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What prevents a device from receiving its own multicast stream, and can it be turned off?
I know that it is normally not possible for a device to receive its own multicast stream on the same network interface where it transmitted said stream. I also understand why this is sensible, and ...
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266
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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 ...
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1
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75
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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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2
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3k
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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 ...
14
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3
answers
5k
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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 ...
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2
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647
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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 ...
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0
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432
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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 ...
- 21
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0
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62
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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 ...
1
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0
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273
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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 ...
- 111
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210
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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 ...
- 183
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2
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123
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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 ...
- 115