420
C
HAPTER
41: M
ULTICAST
O
VERVIEW
Figure 104
Positions of protocols related to multicast
Multicast group management protocol
Internet group management protocol (IGMP) is adopted between a host and its
directly-connected multicast routers. This protocol defines the mechanism of
establishing and maintaining multicast group membership between hosts and
multicast routers.
There are three versions for IGMP currently, including IGMPv1, IGMPv2 and
IGMPv3. A new version is compatible with the old ones.
Multicast routing protocols
A multicast routing protocol operates between multicast routers to establish and
maintain multicast routes and forward multicast packets accurately and effectively.
A multicast route establishes a loop-free data transport path (also known as
multicast distribution tree) from a data source to multiple receivers.
Multicast routes include intra-domain routes and inter-domain routes:
■
Intra-domain multicast routes have been quite mature. Protocol independent
multicast (PIM) is the most commonly used protocol currently. PIM transmits
information to receivers by means of multicast source discovery and multicast
distribution tree establishment. According to forwarding mechanisms, PIM
includes PIM dense mode (PIM-DM) and PIM sparse mode (PIM-SM).
■
The key problem for inter-domain routes is how to transmit information
between autonomous systems (AS). Currently, multicast source discovery
protocol is a relatively mature solution.
Forwarding
Mechanism of
Multicast Packets
In a multicast model, a multicast source host transports information to the
multicast group, which is identified by the multicast group address in the
destination address field of an IP data packet. Unlike a unicast model, a multicast
model must forward data packets to multiple external interfaces so that all
receiver sites can receive the packets. Therefore the forwarding process of
multicast is more complicated than unicast.
AS 1
AS 2
Source
Receiver
Receiver
Receiver
PIM
PIM
MSDP
IGMP
IGMP
IGMP
Summary of Contents for Switch 7754
Page 32: ...32 CHAPTER 1 CLI OVERVIEW ...
Page 70: ...70 CHAPTER 5 LOGGING IN USING MODEM ...
Page 76: ...76 CHAPTER 7 LOGGING IN THROUGH NMS ...
Page 86: ...86 CHAPTER 9 CONFIGURATION FILE MANAGEMENT ...
Page 120: ...120 CHAPTER 13 ISOLATE USER VLAN CONFIGURATION ...
Page 126: ...126 CHAPTER 14 SUPER VLAN ...
Page 136: ...136 CHAPTER 16 IP PERFORMANCE CONFIGURATION ...
Page 152: ...152 CHAPTER 17 IPX CONFIGURATION ...
Page 164: ...164 CHAPTER 19 QINQ CONFIGURATION ...
Page 172: ...172 CHAPTER 21 SHARED VLAN CONFIGURATION ...
Page 182: ...182 CHAPTER 22 PORT BASIC CONFIGURATION ...
Page 198: ...198 CHAPTER 24 PORT ISOLATION CONFIGURATION ...
Page 208: ...208 CHAPTER 25 PORT SECURITY CONFIGURATION ...
Page 224: ...224 CHAPTER 27 DLDP CONFIGURATION ...
Page 232: ...232 CHAPTER 28 MAC ADDRESS TABLE MANAGEMENT ...
Page 240: ...240 CHAPTER 29 CENTRALIZED MAC ADDRESS AUTHENTICATION CONFIGURATION ...
Page 280: ...280 CHAPTER 30 MSTP CONFIGURATION ...
Page 348: ...348 CHAPTER 35 IS IS CONFIGURATION ...
Page 408: ...408 CHAPTER 39 802 1X CONFIGURATION ...
Page 412: ...412 CHAPTER 40 HABP CONFIGURATION ...
Page 422: ...422 CHAPTER 41 MULTICAST OVERVIEW ...
Page 426: ...426 CHAPTER 42 GMRP CONFIGURATION ...
Page 480: ...480 CHAPTER 47 PIM CONFIGURATION ...
Page 506: ...506 CHAPTER 48 MSDP CONFIGURATION ...
Page 552: ...552 CHAPTER 51 TRAFFIC ACCOUNTING CONFIGURATION ...
Page 570: ...570 CHAPTER 53 HA CONFIGURATION ...
Page 582: ...582 CHAPTER 54 ARP CONFIGURATION SwitchA arp protective down recover interval 200 ...
Page 622: ...622 CHAPTER 58 DHCP RELAY AGENT CONFIGURATION ...
Page 684: ...684 CHAPTER 61 QOS CONFIGURATION ...
Page 718: ...718 CHAPTER 63 CLUSTER ...
Page 738: ...738 CHAPTER 67 UDP HELPER CONFIGURATION ...
Page 752: ...752 CHAPTER 69 RMON CONFIGURATION ...
Page 772: ...772 CHAPTER 70 NTP CONFIGURATION ...
Page 796: ...796 CHAPTER 72 FILE SYSTEM MANAGEMENT ...
Page 802: ...802 CHAPTER 73 BIMS CONFIGURATION ...
Page 814: ...814 CHAPTER 74 FTP AND TFTP CONFIGURATION ...
Page 830: ...830 CHAPTER 75 INFORMATION CENTER ...
Page 836: ...836 CHAPTER 76 DNS CONFIGURATION ...
Page 852: ...852 CHAPTER 77 BOOTROM AND HOST SOFTWARE LOADING ...
Page 858: ...858 CHAPTER 78 BASIC SYSTEM CONFIGURATION DEBUGGING ...