3Com 10014298 IGMP Snooping

124 CHAPTER 6: MULTICAST PROTOCOL

IGMP Snooping IGMP Snooping (Internet Group Management Protocol Snooping) is a multicast

control mechanism running on layer 2. It is used for multicast group management

and control.

IGMP Snooping runs on the link layer. When receiving the IGMP messages, the

Switch 7750 uses IGMP Snooping to analyze the information. If the switch hears

an IGMP host report message from an IGMP host, it adds the host to the

corresponding multicast table. If the switch hears IGMP leave a message from an

IGMP host, it will remove the host from the corresponding multicast table. The

switch continuously listens to the IGMP messages to create and maintain a MAC

multicast address table on Layer 2. It can then forward the multicast packets

transmitted from the upstream router according to the MAC multicast address

table.

When IGMP Snooping is disabled, the packets are multicast to all ports. See

Figure 28.

Figure 28 Multicast Packet Transmission Without IGMP Snooping

Packets are not forwarded to all ports when IGMP operates. See Figure 29.

VOD Server

Video stream

Video stream

Video stream Video

stream

Video stream

Multicast

group

member

Nonmulticast

group

member

Nonmulticast

group

member

Layer 2

Ethernet Switch

Multicast router Internet/Intranet

Contents

Main 3Com Corporation 350 Campus Drive Marlborough, MA 01752-3064 C ABOUT THIS GUIDE S YSTEM A PORT CONFIGURATION VLAN C IP ROUTING PROTOCOL OPERATION M ULTICAST P QOS/ OPERATION STP O AAA AND RADIUS OPERATION SYSTEM MANAGEMENT Page Page ABOUT THIS GUIDE This guide describes the 3Com Switch 7750 and how to configure it in version 3.0 of the software. Tabl e 2 lists the text conventions used in this book. Conventions Tabl e 1 Notice Icons Table 2 Text Conventions 1 Product Overview Configuring the Switch 7750 Figure 1 Setting Up the Local Configuration Environment Through the Console Port Table 3 Function Features (continued) Page Page Page Ethernet Page Page Page Page Page Page Page Page Page Page Page Command Line Interface Page Tabl e 20 Function Feature of Command View Page Page Tabl e 23 Editing Functions Tabl e 24 Display Functions Table 22 Retrieve History Command Page 2 Ethernet Port Overview Page Page Page Page Page Page Configuring Link Aggregation Page Page Page Page Page Page Perform the following configuration in Ethernet port view. Tabl e 44 Configure Port Priority Tabl e 45 Display and Debug Link Aggregation Page Page Page 3 VLAN Overview Configuring VLANs Page Page Page Page Page Page 3Configure the protocol VLAN on port G1/0/1 Configuring GARP/GVRP Page Page Page Page Page 4 Configuring IP Address Page Page Configuring Address Resolution Protocol (ARP) Page DHCP Relay Page Page Page Page IP Performance Page Page Page 5 IP Routing Protocol Overview Page Page Static Routes Page Page Page Page RIP Page Page Page Page Page Page Page Page Page IP Routing Policy Page Page Page Page Page Route Capacity Page Page Page 6 IP Multicast Overview Page Page Page Page Configuring Common Multicast Page Configuring IGMP Page Page Page Page Page Page Page IGMP Snooping Page Page Page Page Page Configuring PIM-DM Page Page Page Page Figure 33 PIM-DM Configuration Networking 2Enable PIM-DM. Table 144 Displaying and Debugging PIM-DM Configuring PIM-SM Page Page Page Page Page Page Page Execute the debugging command in user view to debug PIM-SM. Figure 35 PIM-SM Configuration Networking Configure Switch A 1Enable PIM-SM. Tabl e 157 Display and Debug PIM-SM Configure Switch B 1Enable PIM-SM. 2Configure the C-BSR. 3Configure the C-RP. 4Configure PIM domain border. GMRP Page Page 7 ACL Overview Page Configuring ACLs Page Page Page ACL Configuration Examples Page Configuring QoS Page Page Page Page Page Page Page Page Page Tabl e 183 Configuring Traffic Statistics Tabl e 184 Display and Debug QoS Page Page Page Page Page Page Page Configuring ACL Control Page Page Page Page Page 8 STP Overview Configuring STP Page Page Page Page MSTP Overview Page Page Configuring MSTP Page Page Page Page Page Page Page Page Page Perform the following configuration in system view. By default, the switch calculates the default Path Cost of a port by the IEEE 802.1t standard. Tabl e 204 Specifying the Standard To Be Followed in Path Cost Calculation Tabl e 205 Cost Corresponding to the Port Speed of Different Standard Page Page Page Page Page Digest Snooping Page 9 IEEE 802.1x Page Page Page Page Page Page Page Implementing the AAA and RADIUS Protocols Page Configuring AAA Page Page Configuring the RADIUS Protocol Page Page Page Page Page Page Page Page Page Configuring HWTACACS Page Page Page Page Page Page The real-time accounting interval defaults to 12 minutes. Displaying and Debugging the AAA, RADIUS, and HWTACACS Protocols Table 255 Numbers of users and the recommended intervals Tabl e 256 Displaying and Debugging AAA and RADIUS/HWTACACS Protocol AAA, RADIUS, and HWTACACS Protocol Configuration Examples Page Page Troubleshooting AAA, RADIUS, and HWTACACS Configurations Page 11 File System Page Page Page Page Page Managing the MAC Address Table Page Page Page Managing Devices Page Maintaining and Debugging the System Page Page Page Page Page Page The system assigns a channel in each output direction by default. See Tabl e 293. Tabl e 293 Numbers and Names of the Channels for Log Output Tabl e 294 Syslog-Defined Severity Table 292 Log Output (continued) Page Page SNMP Page Page Page Page Page Page Tabl e 310 Enable/Disable Transmission of Trap Information Tabl e 311 Disabling SNMP Agent Tabl e 312 Displaying and Debugging SNMP Page RMON Page Page Page NTP Page Page Page Page Page Page Page Page After the synchronization, SW77502 turns into the following status: