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IGMP

IGMP routing protocol configuration parameter differences between legacy and advanced routing engine.
There are parameter setting differences between legacy and advanced routing engines when configuring Internet Group Management Protocol (IGMP) settings.
Migration Exception:
  • During migration, each entry in the access list is replaced with a sequence number.
  • The advanced routing engine does not apply group permissions directly to specific interfaces.
LEGACY ROUTING ENGINE
ADVANCED ROUTING ENGINE
A legacy routing engine refers to group permissions by name. This applies to IGMPv1, IGMPv2, and IGMPv3 entries.
The advanced routing engine uses extended access lists as filters. Each entry in these access lists uses a sequence number instead of a name. As a result, the entry names are lost and are replaced with a sequence number in the access list during the migration.
A legacy routing engine can apply group permissions directly to specific interfaces.
The advanced routing engine applies group permissions per interface but does not apply group permissions directly to the interfaces. Instead, the advanced routing engine creates an access list (
Logical Routers
Multicast
IGMP
Dynamic
Group Filter
) and then applies the access list to specific interfaces.

IGMP Version Support

Migration Exception:
The legacy routing engine supports IGMPv1, IGMPv2, and IGMPv3 but the advanced routing engine supports only IGMPv2 and IGMPv3.
LEGACY ROUTING ENGINE
ADVANCED ROUTING ENGINE
IGMPv1 supports only two messages: membership query and membership reply. There isn't a separate message supported to announce when a host unsubscribes from a multicast group. Because there is not an explicit leave message, multicast streams can flood a specific segment even when there are no subscribers.
The advanced routing engine supports only IGMPv2 and IGMPv3—support for IGMPv1 is deprecated. However, IGMPv2 is backward compatible and can process IGMPv1 packets.
Differences between IGMPv1 and IGMPv2
FEATURE
IGMPv1
IGMPv2
Default Query Interval (in seconds)
60
125
Max Response Time (in seconds)
10 seconds (fixed)
Range is 0 to 25 seconds (configurable)
Leave Messages
No
Yes
IP Address for Leave Messages
224.0.0.2
Support for Group-Specific Query
No
Yes
Querier Election Mechanism
None (depends on PIM)
Router with the lowest IP address on the subnet.

IGMP Timers

The IGMP timer configuration range varies between legacy and advanced routing engines.
Migration Exception:
The legacy routing engine IGMP timer value is converted during migration to a value within the supported advanced routing engine configuration range.
  • If the IGMP timer configured in the legacy routing engine is a decimal value, then—during migration—it is rounded to the nearest integer value within the valid advanced routing range. This exception impacts the
    Max Query Response Time
    and
    Last Member Query Interval
    .
  • If the IGMP timer configured in the legacy routing engine is an integer value or is migrated to an integer value that exceeds the advanced routing engine configuration range, then this value is changed to a value supported by the advanced routing engine.
CONFIGURED IN (LEGACY ROUTING ENGINE)
LEGACY ROUTING ENGINE
MIGRATED TO (ADVANCED ROUTING ENGINE)
ADVANCED ROUTING ENGINE
Network
Virtual Router
Multicast
Interfaces
IGMP
Supports deciseconds value for few parameters. The legacy routing engine also supports extended ranges for some IGMP parameters.
  • Max Query Response Time
    —Specifies the maximum response time in seconds within which a host must respond to an IGMP query message (range is 0 to 3,174.4; default is 10).
  • Query Interval
    —Specifies the periodic interval in seconds that defines how often the querier sends IGMP host-query messages from an interface (range is 1 to 31,744; default is 125).
  • Last Member Query Interval
    —Specifies the value in seconds that IGMP uses when a router hears an IGMPv2 Leave report. If the interface is not configured for Immediate Leave, the firewall sends a set of group-specific queries at a specified interval. If the querier does not receive a response to the queries, it removes the group state and discontinues multicast transmissions (range is 0.1 to 3,174.4; default is 1).
Network
Routing
Routing Profiles
Multicast
Multicast IPv4 IGMP Interface Query Profiles
Supports the following IGMP timer configurations:
  • Max Query Response Time
    —Specifies the maximum response time in seconds within which a host must respond to an IGMP query message (range is 1 to 25; default is 10).
  • Query Interval
    —Specifies the periodic interval in seconds that defines how often the querier sends IGMP host-query messages from an interface (range is 1 to 1,800; default is 125).
  • Last Member Query Interval
    —Specifies the value in seconds that IGMP uses when a router hears an IGMPv2 Leave report. If the interface is not configured for Immediate Leave option, the firewall sends a set of group-specific queries at a specified interval. If the querier does not receive a response to the queries, it removes the group state and discontinues multicast transmissions (range is 1 to 25; default is 1 second).

IGMP Group Permission

Migration Exception:
A legacy routing engine refers to access list entries by name. The advanced routing engine, instead, identifies access list entries by a sequence number. In the advanced routing engine, the access lists use the source to represent the multicast source and the destination to represent the group.
CONFIGURED IN (LEGACY ROUTING ENGINE)
LEGACY ROUTING ENGINE
ADVANCED ROUTING ENGINE
Network
Virtual Router
Multicast
Interfaces
Group Permissions
Supports the ability to restrict client access to specific groups or specific sources associated with a specific group. These group permissions lists identify each entry by a name and applies to both source-specific and non-source-specific (any source) entries.
Supports extended access lists that restrict access to specific groups or sources associated with a specific group. The advanced routing engine can apply separate access lists to each IGMP-enabled interface. These access lists are defined in the
Filters
routing profile section of the configuration.

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