HP Enterprise HP 3100-8 v2 User manual

HP 3100 v2 Switch Series
IP Multicast
Configuration Guide
HP 3100-8 v2 SI Switch (JG221A)
HP 3100-16 v2 SI Switch (JG222A)
HP 3100-24 v2 SI Switch (JG223A)
HP 3100-8 v2 EI Switch (JD318B)
HP 3100-16 v2 EI Switch (JD319B)
HP 3100-24 v2 EI Switch (JD320B)
HP 3100-8-PoE v2 EI Switch (JD311B)
HP 3100-16-PoE v2 EI Switch (JD312B)
HP 3100-24-PoE v2 EI Switch (JD313B)
Part number: 5998-5994
Software version: Release 5203P05
Document version: 6W100-20140603

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The information contained herein is subject to change without notice.
HEWLETT-PACKARD COMPANY MAKES NO WARRANTY OF ANY KIND WITH REGARD TO THIS
MATERIAL, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
AND FITNESS FOR A PARTICULAR PURPOSE. Hewlett-Packard shall not be liable for errors contained
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herein.

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Contents
Multicast overview ······················································································································································· 1
Introduction to multicast····················································································································································1
Information transmission techniques·······················································································································1
Multicast features······················································································································································3
Common notations in multicast ·······························································································································4
Multicast advantages and applications ·················································································································4
Multicast models································································································································································5
Multicast architecture························································································································································5
Multicast addresses ··················································································································································6
Multicast protocols ···················································································································································9
Multicast packet forwarding mechanism····················································································································· 11
Configuring IGMP snooping ·····································································································································12
Overview········································································································································································· 12
Basic concepts in IGMP snooping······················································································································· 12
How IGMP snooping works ································································································································· 14
IGMP snooping proxying ····································································································································· 15
Protocols and standards ······································································································································· 17
IGMP snooping configuration task list························································································································· 17
Configuring basic IGMP snooping functions ·············································································································· 18
Enabling IGMP snooping ····································································································································· 18
Specifying the version of IGMP snooping ·········································································································· 18
Configuring static multicast MAC address entries ····························································································· 19
Configuring IGMP snooping port functions················································································································· 20
Setting aging timers for dynamic ports ··············································································································· 20
Configuring static ports········································································································································· 21
Configuring a port as a simulated member host ······························································································· 21
Enabling IGMP snooping fast-leave processing································································································· 22
Disabling a port from becoming a dynamic router port ··················································································· 23
Configuring IGMP snooping querier ··························································································································· 24
Enabling IGMP snooping querier ························································································································ 24
Configuring parameters for IGMP queries and responses ··············································································· 24
Configuring the source IP addresses for IGMP queries····················································································· 25
Configuring IGMP snooping proxying ························································································································ 26
Enabling IGMP snooping proxying····················································································································· 26
Configuring a source IP address for the IGMP messages sent by the proxy·················································· 26
Configuring an IGMP snooping policy························································································································ 27
Configuring a multicast group filter····················································································································· 27
Configuring multicast source port filtering·········································································································· 28
Enabling dropping unknown multicast data······································································································· 29
Configuring IGMP report suppression ················································································································ 29
Setting the maximum number of multicast groups that a port can join ··························································· 30
Enabling multicast group replacement················································································································ 30
Setting the 802.1p precedence for IGMP messages ························································································ 31
Configuring a multicast user control policy (available only on the HP 3100 v2 EI)······································ 32
Enabling the IGMP snooping host tracking function ························································································· 32
Setting the DSCP value for IGMP messages······································································································· 33
Displaying and maintaining IGMP snooping·············································································································· 33
IGMP snooping configuration examples ····················································································································· 34

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Group policy and simulated joining configuration example············································································ 34
Static port configuration example ······················································································································· 36
IGMP snooping querier configuration example································································································· 40
IGMP snooping proxying configuration example······························································································ 42
Multicast source and user control policy configuration example (available only on the HP 3100 v2 EI)··· 44
Troubleshooting IGMP snooping ·································································································································· 49
Layer 2 multicast forwarding cannot function ···································································································· 49
Configured multicast group policy fails to take effect ······················································································· 49
Configuring multicast VLANs·····································································································································51
Overview········································································································································································· 51
Multicast VLAN configuration task list ························································································································· 52
Configuring a port-based multicast VLAN··················································································································· 52
Configuration prerequisites ·································································································································· 52
Configuring user port attributes ··························································································································· 53
Configuring multicast VLAN ports ······················································································································· 53
Displaying and maintaining multicast VLAN··············································································································· 54
Multicast VLAN configuration examples······················································································································ 54
Configuring MLD snooping (available only on the HP 3100 v2 EI) ······································································58
Overview········································································································································································· 58
Basic concepts in MLD snooping························································································································· 58
How MLD snooping works ··································································································································· 60
MLD snooping proxying ······································································································································· 61
Protocols and standards ······································································································································· 62
MLD snooping configuration task list ··························································································································· 62
Configuring basic MLD snooping functions ················································································································ 63
Enabling MLD snooping ······································································································································· 64
Specifying the version of MLD snooping ············································································································ 64
Configuring IPv6 static multicast MAC address entries····················································································· 65
Configuring MLD snooping port functions··················································································································· 65
Configuring aging timers for dynamic ports ······································································································ 66
Configuring static ports········································································································································· 66
Configuring a port as a simulated member host ······························································································· 67
Enabling fast-leave processing····························································································································· 68
Disabling a port from becoming a dynamic router port ··················································································· 68
Configuring MLD snooping querier ····························································································································· 69
Enabling MLD snooping querier ·························································································································· 69
Configuring parameters for MLD queries and responses ················································································· 70
Configuring the source IPv6 addresses for MLD queries ·················································································· 71
Configuring MLD snooping proxying ·························································································································· 71
Enabling MLD snooping proxying······················································································································· 71
Configuring the source IPv6 addresses for the MLD messages sent by the proxy ········································· 72
Configuring an MLD snooping policy·························································································································· 72
Configuring an IPv6 multicast group filter ·········································································································· 72
Enabling dropping unknown IPv6 multicast data ······························································································ 73
Configuring MLD report suppression ·················································································································· 74
Setting the maximum number of multicast groups that a port can join ··························································· 74
Enabling IPv6 multicast group replacement ······································································································· 75
Setting the 802.1p precedence for MLD messages ·························································································· 76
Configuring an IPv6 multicast user control policy······························································································ 76
Enabling the MLD snooping host tracking function ··························································································· 77
Setting the DSCP value for MLD messages········································································································· 78
Displaying and maintaining MLD snooping················································································································ 78
MLD snooping configuration examples ······················································································································· 79

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IPv6 group policy and simulated joining configuration example ···································································· 79
Static port configuration example ······················································································································· 81
MLD snooping querier configuration example··································································································· 84
MLD snooping proxying configuration example································································································ 86
IPv6 multicast source and user control policy configuration example ····························································· 89
Troubleshooting MLD snooping ···································································································································· 93
Layer 2 multicast forwarding cannot function ···································································································· 93
Configured IPv6 multicast group policy fails to take effect··············································································· 94
Configuring IPv6 multicast VLANs (available only on the HP 3100 v2 EI) ···························································95
Overview········································································································································································· 95
IPv6 multicast VLAN configuration task list ················································································································· 96
Configuring a port-based IPv6 multicast VLAN ·········································································································· 96
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Configuring user port attributes ··························································································································· 97
Configuring IPv6 multicast VLAN ports ··············································································································· 97
Displaying and maintaining IPv6 multicast VLAN ······································································································ 98
IPv6 multicast VLAN configuration examples·············································································································· 98
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1
Multicast overview
Introduction to multicast
As a technique that coexists with unicast and broadcast, the multicast technique effectively addresses the
issue of point-to-multipoint data transmission. By enabling high-efficiency point-to-multipoint data
transmission over a network, multicast greatly saves network bandwidth and reduces network load.
By using multicast technology, a network operator can easily provide new value-added services, such as
live webcasting, web TV, distance learning, telemedicine, web radio, real time video conferencing, and
other bandwidth-critical and time-critical information services.
The term "router " in this document refers to both routers and Layer 3 switches.
Unless otherwise stated, the term "multicast" in this document refers to IP multicast.
Information transmission techniques
The information transmission techniques include unicast, broadcast, and multicast.
Unicast
In unicast transmission, the information source must send a separate copy of information to each host that
needs the information.
Figure 1 Unicast transmission
In Figure 1, assume that Host B, Host D and Host E need the information. A separate transmission channel
must be established from the information source to each of these hosts.
Source
Receiver
Receiver
Receiver
Host A
Host B
Host C
Host D
Host E
Packets for Host B
Packets for Host D
Packets for Host E
IP network

2
In unicast transmission, the traffic transmitted over the network is proportional to the number of hosts that
need the information. If a large number of hosts need the information, the information source must send
a separate copy of the same information to each of these hosts. Sending many copies can place a
tremendous pressure on the information source and the network bandwidth.
Unicast is not suitable for batch transmission of information.
Broadcast
In broadcast transmission, the information source sends information to all hosts on the subnet, even if
some hosts do not need the information.
Figure 2 Broadcast transmission
In Figure 2, assume that only Host B, Host D, and Host E need the information. If the information is
broadcast to the subnet, Host A and Host C also receive it. In addition to information security issues,
broadcasting to hosts that do not need the information also causes traffic flooding on the same subnet.
Broadcast is disadvantageous in transmitting data to specific hosts. Moreover, broadcast transmission is
a significant waste of network resources.
Multicast
Unicast and broadcast techniques cannot provide point-to-multipoint data transmissions with the
minimum network consumption.
Multicast transmission can solve this problem. When some hosts on the network need multicast
information, the information sender, or multicast source, sends only one copy of the information.
Multicast distribution trees are built through multicast routing protocols, and the packets are replicated
only on nodes where the trees branch.

3
Figure 3 Multicast transmission
The multicast source sends only one copy of the information to a multicast group. Host B, Host D and Host
E, which are receivers of the information, must join the multicast group. The routers on the network
duplicate and forward the information based on the distribution of the group members. Finally, the
information is correctly delivered to Host B, Host D, and Host E.
To summarize, multicast has the following advantages:
•Advantages over unicast—Because multicast traffic flows to the farthest-possible node from the
source before it is replicated and distributed, an increase in the number of hosts does not increase
the load of the source or remarkably add to the usage of network resources.
•Advantages over broadcast—Because multicast data is sent only to the receivers that need it,
multicast uses network bandwidth reasonably and enhances network security. In addition, data
broadcast is confined to the same subnet, but multicast is not.
Multicast features
•A multicast group is a multicast receiver set identified by an IP multicast address. Hosts join a
multicast group to become members of the multicast group before they can receive the multicast
data addressed to that multicast group. Typically, a multicast source does not need to join a
multicast group.
•An information sender is called a "multicast source". A multicast source can send data to multiple
multicast groups at the same time, and multiple multicast sources can send data to the same
multicast group at the same time.
•All hosts that have joined a multicast group become members of the multicast group. The group
memberships are dynamic. Hosts can join or leave multicast groups at any time. Multicast groups
are not subject to geographic restrictions.
•Routers or Layer 3 switches that support Layer 3 multicast are called "multicast routers" or "Layer 3
multicast devices". In addition to providing the multicast routing function, a multicast router can also
manage multicast group memberships on stub subnets with attached group members. A multicast
router itself can be a multicast group member.

4
For a better understanding of the multicast concept, you can compare multicast transmission to the
transmission of TV programs.
Table 1 Comparing TV program transmission and multicast transmission
TV transmission
Multicast transmission
A TV station transmits a TV program through a
channel.
A multicast source sends multicast data to a multicast
group.
A user tunes the TV set to the channel. A receiver joins the multicast group.
The user starts to watch the TV program transmitted
by the TV station via the channel.
The receiver starts to receive the multicast data that the
source is sending to the multicast group.
The user turns off the TV set or tunes to another
channel.
The receiver leaves the multicast group or joins another
group.
Common notations in multicast
The following notations are commonly used in multicast transmission:
•(*, G)—Indicates a rendezvous point tree (RPT), or a multicast packet that any multicast source sends
to multicast group G. Here, the asterisk represents any multicast source, and "G" represents a
specific multicast group.
•(S, G)—Indicates a shortest path tree (SPT), or a multicast packet that multicast source S sends to
multicast group G. Here, "S" represents a specific multicast source, and "G" represents a specific
multicast group.
Multicast advantages and applications
Multicast advantages
Advantages of the multicast technique include the following:
•Enhanced efficiency—Reduces the processor load of information source servers and network
devices.
•Optimal performance—Reduces redundant traffic.
•Distributed application—Enables point-to-multipoint applications at the price of minimum network
resources.
Multicast applications
The scenarios in which the multicast technique can be effectively applied are:
•Multimedia and streaming applications, such as web TV, web radio, and real time video/audio
conferencing
•Communication for training and cooperative operations, such as distance learning and
telemedicine
•Data warehouse and financial applications (stock quotes)
•Any other point-to-multipoint application for data distribution

5
Multicast models
Based on how the receivers treat the multicast sources, the multicast models include any-source multicast
(ASM), source-filtered multicast (SFM), and source-specific multicast (SSM).
ASM model
In the ASM model, any sender can send information to a multicast group as a multicast source, and
receivers can join a multicast group (identified by a group address) and obtain multicast information
addressed to that multicast group. In this model, receivers do not know the positions of the multicast
sources in advance. However, they can join or leave the multicast group at any time.
SFM model
The SFM model is derived from the ASM model. To a sender, the two models appear to have the same
multicast membership architecture.
The SFM model functionally extends the ASM model. The upper-layer software checks the source address
of received multicast packets and permits or denies multicast traffic from specific sources. Therefore,
receivers can receive the multicast data from only part of the multicast sources. To a receiver, multicast
sources are not all valid; they are filtered.
SSM model
Users might be interested in the multicast data from only certain multicast sources. The SSM model
provides a transmission service that enables users to specify the multicast sources that they are interested
in at the client side.
The main difference between the SSM model and the ASM model is that in the SSM model, receivers
have already determined the locations of the multicast sources by some other means. In addition, the
SSM model uses a multicast address range that is different from that of the ASM/SFM model, and
dedicated multicast forwarding paths are established between receivers and the specified multicast
sources.
Multicast architecture
IP multicast addresses the following questions:
•Where should the multicast source transmit information to? (Multicast addressing.)
•What receivers exist on the network? (Host registration.)
•Where is the multicast source that will provide data to the receivers? (Multicast source discovery.)
•How should information be transmitted to the receivers? (Multicast routing.)
IP multicast is an end-to-end service. The multicast architecture involves the following parts:
•Addressing mechanism—A multicast source sends information to a group of receivers through a
multicast address.
•Host registration—Receiver hosts can join and leave multicast groups dynamically. This mechanism
is the basis for management of group memberships.
•Multicast routing—A multicast distribution tree (a forwarding path tree for multicast data on the
network) is constructed for delivering multicast data from a multicast source to receivers.
•Multicast applications—A software system that supports multicast applications, such as video
conferencing, must be installed on multicast sources and receiver hosts. The TCP/IP stack must
support reception and transmission of multicast data.