HP 6125XLG R2306-HP 6125XLG Blade Switch IP Multicast Configuration Guide - Page 59

Enhancements in query and report capabilities, IS_IN, IS_EX

Page 59 highlights

• If the host expects to receive multicast data from specific sources like S1, S2, ..., it sends a report with the Filter-Mode denoted as "Include Sources (S1, S2, ...)." • If the host expects to reject multicast data from specific sources like S1, S2, ..., it sends a report with the Filter-Mode denoted as "Exclude Sources (S1, S2, ...)". As shown in Figure 22, the network comprises two multicast sources, Source 1 (S1) and Source 2 (S2), both of which can send multicast data to the multicast group G. Host B is interested in the multicast data that Source 1 sends to G but not in the data from Source 2. Figure 22 Flow paths of source-and-group-specific multicast traffic In IGMPv1 or IGMPv2, Host B cannot select multicast sources when it joins the multicast group G, and multicast streams from both Source 1 and Source 2 flow to Host B whether or not it needs them. When IGMPv3 runs between the hosts and routers, Host B can explicitly express that it needs to receive the multicast data that Source 1 sends to the multicast group G (denoted as (S1, G)), rather than the multicast data that Source 2 sends to multicast group G (denoted as (S2, G)). Only multicast data from Source 1 is delivered to Host B. Enhancements in query and report capabilities • Query message carrying the source addresses: Compatible with IGMPv1 and IGMPv2, IGMPv3 supports general queries and group-specific queries. It also introduces group-and-source-specific queries. { A general query does not carry a group address or a source address. { A group-specific query carries a group address, but no source address. { A group-and-source-specific query carries a group address and one or more source addresses. • Reports containing multiple group records: Unlike an IGMPv1 or IGMPv2 report message, an IGMPv3 report message is destined to 224.0.0.22 and contains one or more group records. Each group record contains a multicast group address and a multicast source address list. Group records include the following categories: { IS_IN-The source filtering mode is Include. The report sender requests the multicast data from only the sources defined in the specified multicast source list. { IS_EX-The source filtering mode is Exclude. The report sender requests the multicast data from any sources except those defined in the specified multicast source list. 52

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52
If the host expects to receive multicast data from specific sources like S1, S2, …, it sends a report
with the Filter-Mode denoted as "Include Sources (S1, S2, …)."
If the host expects to reject multicast data from specific sources like S1, S2, …, it sends a report with
the Filter-Mode denoted as "Exclude Sources (S1, S2, …)".
As shown in
Figure 22
, the network comprises two multicast sources, Source 1 (S1) and Source 2 (S2),
both of which can send multicast data to the multicast group G. Host B is interested in the multicast data
that Source 1 sends to G but not in the data from Source 2.
Figure 22
Flow paths of source-and-group-specific multicast traffic
In IGMPv1 or IGMPv2, Host B cannot select multicast sources when it joins the multicast group G, and
multicast streams from both Source 1 and Source 2 flow to Host B whether or not it needs them.
When IGMPv3 runs between the hosts and routers, Host B can explicitly express that it needs to receive
the multicast data that Source 1 sends to the multicast group G (denoted as (S1, G)), rather than the
multicast data that Source 2 sends to multicast group G (denoted as (S2, G)). Only multicast data from
Source 1 is delivered to Host B.
Enhancements in query and report capabilities
Query message carrying the source addresses:
Compatible with IGMPv1 and IGMPv2, IGMPv3 supports general queries and group-specific
queries. It also introduces group-and-source-specific queries.
{
A general query does not carry a group address or a source address.
{
A group-specific query carries a group address, but no source address.
{
A group-and-source-specific query carries a group address and one or more source addresses.
Reports containing multiple group records:
Unlike an IGMPv1 or IGMPv2 report message, an IGMPv3 report message is destined to
224.0.0.22 and contains one or more group records. Each group record contains a multicast
group address and a multicast source address list.
Group records include the following categories:
{
IS_IN
—The source filtering mode is Include. The report sender requests the multicast data from
only the sources defined in the specified multicast source list.
{
IS_EX
—The source filtering mode is Exclude. The report sender requests the multicast data from
any sources except those defined in the specified multicast source list.