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IGMP Snooping Commands
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IGMP Snooping Commands
Snooping of Internet Group Management Protocol (IGMP) messages is a
feature that allows PowerConnect switches to forward multicast traffic
intelligently on the switch. Multicast IP traffic is traffic that is destined to a
host group. Host groups are identified by class D IP addresses, which range
from 224.0.0.0 to 239.255.255.255. Based on the IGMP query and report
messages, the switch forwards traffic only to the ports that request the
multicast traffic. This prevents the switch from broadcasting the traffic to all
ports and possibly affecting network performance.
IGMP snooping switches build forwarding lists by monitoring for, and in
some cases intercepting, IGMP messages. Although the software processing
the IGMP messages could maintain state information based on the full IP
group addresses, the forwarding tables in PowerConnect are mapped to link
layer addresses.
The Multicast Forwarding Database (MFDB) manages the forwarding
address table for Layer 2 multicast protocols, such as IGMP Snooping.
The IGMP Snooping code in the CPU ages out IGMP entries in the MFDB.
If a report for a particular group on a particular interface is not received
within a certain time interval (query interval), the IGMP Snooping code
deletes that interface from the group. The value for query interval time is
configurable using management.
If an IGMP Leave Group message is received on an interface, the IGMP
Snooping code sends a query on that interface and waits a specified length of
time (maximum response time). If no response is received within that time,
that interface is removed from the group. The value for maximum response
time is configurable using management.
In addition to building and maintaining lists of multicast group
memberships, the snooping switch also maintains a list of multicast routers.
When forwarding multicast packets, they should be forwarded on ports that
have joined using IGMP and also on ports on which multicast routers are
attached. The reason for this is that in IGMP there is only one active query
mechanism. This means that all other routers on the network are suppressed
and thus not detectable by the switch. If a query is not received on an
2CSPC4.XCT-SWUM2XX1.book Page 479 Monday, October 3, 2011 11:05 AM
Содержание PowerConnect 7000 Series
Страница 74: ...74 Contents 2CSPC4 XCT SWUM2XX1 book Page 74 Monday October 3 2011 11 05 AM ...
Страница 164: ...164 Command Groups 2CSPC4 XCT SWUM2XX1 book Page 164 Monday October 3 2011 11 05 AM ...
Страница 238: ...238 Layer 2 Switching Commands 2CSPC4 XCT SWUM2XX1 book Page 238 Monday October 3 2011 11 05 AM ...
Страница 266: ...266 AAA Commands 2CSPC4 XCT SWUM2XX1 book Page 266 Monday October 3 2011 11 05 AM ...
Страница 316: ...316 Auto VoIP Commands 2CSPC4 XCT SWUM2XX1 book Page 316 Monday October 3 2011 11 05 AM ...
Страница 344: ...344 DHCP Layer 2 Relay Commands 2CSPC4 XCT SWUM2XX1 book Page 344 Monday October 3 2011 11 05 AM ...
Страница 352: ...352 DHCP Management Interface Commands 2CSPC4 XCT SWUM2XX1 book Page 352 Monday October 3 2011 11 05 AM ...
Страница 368: ...368 DHCP Snooping Commands 2CSPC4 XCT SWUM2XX1 book Page 368 Monday October 3 2011 11 05 AM ...
Страница 382: ...382 Dynamic ARP Inspection Commands 2CSPC4 XCT SWUM2XX1 book Page 382 Monday October 3 2011 11 05 AM ...
Страница 434: ...434 Ethernet Configuration Commands 2CSPC4 XCT SWUM2XX1 book Page 434 Monday October 3 2011 11 05 AM ...
Страница 454: ...454 Ethernet CFM Commands 2CSPC4 XCT SWUM2XX1 book Page 454 Monday October 3 2011 11 05 AM ...
Страница 468: ...468 Green Ethernet Commands 2CSPC4 XCT SWUM2XX1 book Page 468 Monday October 3 2011 11 05 AM ...
Страница 532: ...532 IPv6 Access List Commands 2CSPC4 XCT SWUM2XX1 book Page 532 Monday October 3 2011 11 05 AM ...
Страница 544: ...544 IPv6 MLD Snooping Commands 2CSPC4 XCT SWUM2XX1 book Page 544 Monday October 3 2011 11 05 AM ...
Страница 558: ...558 IP Source Guard Commands 2CSPC4 XCT SWUM2XX1 book Page 558 Monday October 3 2011 11 05 AM ...
Страница 570: ...570 iSCSI Optimization Commands 2CSPC4 XCT SWUM2XX1 book Page 570 Monday October 3 2011 11 05 AM ...
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Страница 606: ...606 LLDP Commands 2CSPC4 XCT SWUM2XX1 book Page 606 Monday October 3 2011 11 05 AM ...
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Страница 808: ...808 VLAN Commands 2CSPC4 XCT SWUM2XX1 book Page 808 Monday October 3 2011 11 05 AM ...
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Страница 1234: ...1234 OSPFv3 Commands 2CSPC4 XCT SWUM2XX1 book Page 1234 Monday October 3 2011 11 05 AM ...
Страница 1244: ...1244 Router Discovery Protocol Commands 2CSPC4 XCT SWUM2XX1 book Page 1244 Monday October 3 2011 11 05 AM ...
Страница 1260: ...1260 Routing Information Protocol Commands 2CSPC4 XCT SWUM2XX1 book Page 1260 Monday October 3 2011 11 05 AM ...
Страница 1292: ...1292 Virtual Router Redundancy Protocol Commands 2CSPC4 XCT SWUM2XX1 book Page 1292 Monday October 3 2011 11 05 AM ...
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