15-1
C
HAPTER
15
M
ULTICAST
F
ILTERING
Multicasting is used to support real-time
applications such as videoconferencing
or streaming audio. A multicast server
does not have to establish a separate
connection with each client. It merely
broadcasts its service to the network, and
any hosts that want to receive the
multicast register with their local
multicast switch/router. Although this
approach reduces the network overhead
required by a multicast server, the
broadcast traffic must be carefully
pruned at every multicast switch/router it
passes through to ensure that traffic is
only passed on to the hosts which
subscribed to this service.
This switch can use Internet Group Management Protocol (IGMP) to
filter multicast traffic. IGMP Snooping can be used to passively monitor or
“snoop” on exchanges between attached hosts and an IGMP-enabled
device, most commonly a multicast router. In this way, the switch can
discover the ports that want to join a multicast group, and set its filters
accordingly.
If there is no multicast router attached to the local subnet, multicast traffic
and query messages may not be received by the switch. In this case (Layer
2) IGMP Query can be used to actively ask the attached hosts if they want
to receive a specific multicast service. IGMP Query thereby identifies the
ports containing hosts requesting to join the service and sends data out to
Unicast
Flow
Multicast
Flow
Содержание 7824M/FSW - annexe 1
Страница 2: ......
Страница 24: ...TABLE OF CONTENTS xxiv ...
Страница 28: ...TABLES xxviii ...
Страница 32: ...FIGURES xxxii Figure 16 3 DNS Cache 16 7 ...
Страница 34: ...GETTING STARTED ...
Страница 46: ...SYSTEM DEFAULTS 1 12 ...
Страница 62: ...SWITCH MANAGEMENT ...
Страница 74: ...CONFIGURING THE SWITCH 3 12 ...
Страница 112: ...BASIC MANAGEMENT TASKS 4 38 ...
Страница 168: ...USER AUTHENTICATION 6 30 ...
Страница 223: ...SHOWING PORT STATISTICS 9 33 Figure 9 12 Port Statistics ...
Страница 230: ...ADDRESS TABLE SETTINGS 10 6 ...
Страница 304: ...CLASS OF SERVICE 13 16 ...
Страница 316: ...QUALITY OF SERVICE 14 12 ...
Страница 338: ...MULTICAST FILTERING 15 22 ...
Страница 346: ...DOMAIN NAME SERVICE 16 8 ...
Страница 348: ...COMMAND LINE INTERFACE IP Interface Commands 35 1 ...
Страница 362: ...OVERVIEW OF COMMAND LINE INTERFACE 17 14 ...
Страница 426: ...SYSTEM MANAGEMENT COMMANDS 19 56 Example Console show calendar 15 12 34 February 1 2002 Console ...
Страница 494: ...USER AUTHENTICATION COMMANDS 21 48 ...
Страница 514: ...CLIENT SECURITY COMMANDS 22 20 ...
Страница 540: ...ACCESS CONTROL LIST COMMANDS 23 26 ...
Страница 558: ...INTERFACE COMMANDS 24 18 ...
Страница 576: ...MIRROR PORT COMMANDS 26 4 ...
Страница 582: ...RATE LIMIT COMMANDS 27 6 ...
Страница 616: ...SPANNING TREE COMMANDS 29 28 ...
Страница 644: ...VLAN COMMANDS 30 28 ...
Страница 664: ...CLASS OF SERVICE COMMANDS 31 20 ...
Страница 678: ...QUALITY OF SERVICE COMMANDS 32 14 ...
Страница 720: ...APPENDICES ...
Страница 726: ...SOFTWARE SPECIFICATIONS A 6 ...
Страница 730: ...TROUBLESHOOTING B 4 ...
Страница 746: ...INDEX Index 6 ...
Страница 747: ......