186
C
HAPTER
15: M
ULTICAST
O
VERVIEW
the server must send many pieces of information with the same content to the
users. Therefore, the limited bandwidth becomes the bottleneck in information
transmission. This shows that unicast is not good for the transmission of a great
deal of information.
Information
Transmission in the
Broadcast Mode
When you adopt broadcast, the system transmits information to all users on a
network. Any user on the network can receive the information, no matter the
information is needed or not. Figure 56 shows information transmission in
broadcast mode.
Figure 56
Information transmission in the broadcast mode
Assume that Hosts B, D, and E need the information. The source server broadcasts
this information through routers, and Hosts A and C on the network also receive
this information.
As we can see from the information transmission process, the security and legal
use of paid service cannot be guaranteed. In addition, when only a small number
of users on the same network need the information, the utilization ratio of the
network resources is very low and the bandwidth resources are greatly wasted.
Therefore, broadcast is disadvantageous in transmitting data to specific users;
moreover, broadcast occupies large bandwidth.
Information
Transmission in the
Multicast Mode
As described in the previous sections, unicast is suitable for networks with sparsely
distributed users, whereas broadcast is suitable for networks with densely
distributed users. When the number of users requiring information is not certain,
unicast and broadcast deliver a low efficiency.
Multicast solves this problem. When some users on a network require specified
information, the multicast information sender (namely, the multicast source) sends
Source
Server
Receiver
Receiver
Receiver
Host A
Host B
Host C
Host D
Host E
Packets for all the network
Содержание Switch 4210 9-Port
Страница 10: ...Password Control Configuration 556 Displaying Password Control 563 Password Control Configuration Example 564 ...
Страница 22: ...20 CHAPTER 1 CLI CONFIGURATION ...
Страница 74: ...72 CHAPTER 3 CONFIGURATION FILE MANAGEMENT ...
Страница 84: ...82 CHAPTER 5 VLAN CONFIGURATION ...
Страница 96: ...94 CHAPTER 8 IP PERFORMANCE CONFIGURATION ...
Страница 108: ...106 CHAPTER 9 PORT BASIC CONFIGURATION ...
Страница 122: ...120 CHAPTER 11 PORT ISOLATION CONFIGURATION ...
Страница 140: ...138 CHAPTER 13 MAC ADDRESS TABLE MANAGEMENT ...
Страница 234: ...232 CHAPTER 17 802 1X CONFIGURATION ...
Страница 246: ...244 CHAPTER 20 AAA OVERVIEW ...
Страница 270: ...268 CHAPTER 21 AAA CONFIGURATION ...
Страница 292: ...290 CHAPTER 26 DHCP BOOTP CLIENT CONFIGURATION ...
Страница 318: ...316 CHAPTER 29 MIRRORING CONFIGURATION ...
Страница 340: ...338 CHAPTER 30 CLUSTER ...
Страница 362: ...360 CHAPTER 33 SNMP CONFIGURATION ...
Страница 368: ...366 CHAPTER 34 RMON CONFIGURATION ...
Страница 450: ...448 CHAPTER 39 TFTP CONFIGURATION ...
Страница 451: ......
Страница 452: ...450 CHAPTER 39 TFTP CONFIGURATION ...
Страница 470: ...468 CHAPTER 40 INFORMATION CENTER ...
Страница 496: ...494 CHAPTER 44 DEVICE MANAGEMENT ...