webinar netgear - prosafe switch - come configurare il supporto del multicast

ProSAFE Switch Series

Configurare il Multicast

Andrea RossiSenior System Engineer

[email protected]

Formazione Online

What is Multicast?

Multicast (one-to-many or many-to-many distribution) is group communication

where data is addressed to a group of destination devices.

What is Multicast?

Multicast (one-to-many or many-to-many distribution) is group communication

where data is addressed to a group of destination devices.

BROADCAST UNICAST

MULTICAST

What is Multicast?

The multicast addresses are in the range 224.0.0.0 through 239.255.255.255

239.0.0.0-239.255.255.255 Organization-Local Scope

Network assisted multicast may be implemented at the Internet layer using IP

multicast, which is often employed in IP applications of streaming media, such as

IPTV scheduled content (but not media-on-demand) and multipoint

videoconferencing, but also for ghost distribution of backup disk images to

multiple computers simultaneously. In IP multicast the implementation of the

multicast concept occurs at the IP routing level, where routers create optimal

distribution paths for datagrams sent to a multicast destination address.

Internet Group Management Protocol (IGMP)

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• When the switch is used in network applications where video services such as IPTV, video

streaming, and gaming are deployed, the video traffic is normally flooded to all connected ports

because such traffic packets usually have multicast Ethernet addresses. IGMP snooping can be

enabled to create a multicast group to direct that traffic only to those users that require it.

• However, the IGMP snooping operation usually requires an extra network device—usually a

router—that can generate an IGMP membership query and solicit interested nodes to respond.

With the built-in IGMP querier feature inside the switch, such an external device is no longer

needed.

• Since the IGMP querier is designed to work with IGMP snooping, it is necessary to enable IGMP

snooping when using it.

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Host A

Reciever

Multicast Router / IGMP Snooping

Network Without IGMP Snooping

Source

IGMP Querier

Host B Host C

Switch

Host A

Reciever

Source

IGMP Querier

Host B Host C

Switch (IGMP Snooping)

Network With IGMP Snooping

First lets look at IGMP Snooping and how it effects the flow of traffic. Without

it multicast traffic in a network is essentially treated as a broadcast and

forwarded to all ports, regardless of the whether the host on the port is a

receiver for it or not. Once IGMP Snooping is configured then the traffic flow

becomes much more efficient, with only receiver hosts needing the traffic.

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Multicast Router / IGMP Snooping

IGMP Querier

Host A

Reciever

Source

IGMP Querier

Host B Host C


IGMP Querier / IGMP Snooping

As discussed at the beginning of the module lets now look at the network

design when the Querier / Snooping reside in the same NETGEAR Managed

Switch. Here we negate the need for an external device to act as the querier.

Host A

Reciever

Source

IGMP Querier

Host B


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Multicast with VLC using IGMP

For this example, we will use the VLC Media Player to stream a video to

specific ports on a VLAN.

For the first part we’ll use IGMP Snooping and Querier.

IGMP Switch Configuration:

1. Create routed VLAN 10 with IP address 192.168.10.254/24

2. Use the switch to provide DCHP services for VLAN1 and VLAN10

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3. Go to “Switching => Multicast => IGMP Snooping => IGMP Snooping

Configuration”.

4. Enable “Admin Mode” and “Apply” settings.

5. Go to “IGMP VLAN Configuration”, add VLAN ID 10 and enable Admin

Mode.

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6. Go to “IGMP Snooping Querier Configuration”

• Enable Querier Admin Mode

• Enter 192.168.10.254 as the Snooping Querier Address

• VLAN10 should show as the enabled VLAN ID

7. The “IGMP Snooping Querier VLAN Configuration” should show the

Querier in operational state:

Multicast VLAN Registration (MVR)

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As we know IGMP Snooping Protocol resolves the issue of multicast streams being received by unwanted

ports. However the problem re-appears when we try to stream multicast traffic across different VLANs.

Multicast VLAN Registration (MVR) is intended to solve the problem of receivers in different VLANs. It uses

a dedicated manually configured VLAN, called the multicast VLAN, to forward multicast traffic over Layer 2

network in conjunction with IGMP snooping.

There are two types of MVR ports: source and receiver.

The source port is the port to which the multicast traffic flows using the multicast VLAN.

The receiver port is the port where a listening host is connected to the switch. It can utilize any (or no)

VLAN, except the multicast VLAN. This implies that the MVR switch performs VLAN tag substitution from

the multicast VLAN source port to the VLAN tag used by the receiver port.

Host A

Reciever Port

VLAN 10

Host B

Receiver Port

VLAN 20

Source Port (VLAN999)

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Multicast with VLC using IGMP and MVR

1. To enable MVR, go to “Switching => MVR => Basic” and “Enable” MVR

Running setting:

2. Go to “MVR => Advanced => MVR Interface Configuration” and select the

“source” port as the VLC Server and VLAN1 ports as the “receiver” ports:

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Multicast with VLC using IGMP and MVR

3. The “MVR Group Configuration” should now show as “Active”:

4. The “MVR Group Membership” should now reflect the source and

receiver ports:

Now connect a PC to a designated receiver port in routed VLAN1 and try to

run the stream.

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VLC streaming device config

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2

3

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VLC streaming device config

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VLC receiver device config

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2

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Switch Families

Prosafe SwitchMulticast support

Footer use for Presentation Title or footnotes19


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Multicast Group: 1024


28 Multicast Group: 2048

webinar netgear - prosafe switch - come configurare il supporto del multicast

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