Operation Manual – MulticastH3C S7500 Series Ethernet Switches Chapter 4 Common Multicast Configuration4-4Caution:z During the configuration, if the seconds argument is less than 15, the system setsthe holdtime to 15; if the seconds argument is more than 15, the system sets theholdtime to the multiples of 15 according to the user-defined range. For example, ifyou set the seconds argument to 14, the system sets the holdtime to 15; if you setthe seconds argument to 16, the system sets the holdtime to 30; if you set theseconds argument to 31, the system sets the holdtime to 45, and so on.z When the holdtime is set to 0, the report of CPU packets to the CPU is notsuppressed.4.2.4 Configuring Static Router PortsI. IntroductionIn a ring network or a network with double uplinks, users usually configure both primaryand secondary links over a connection in order to avoid communication interruptiondue to link failure. When the primary link fails, the secondary link can replace itimmediately to avoid communication interruption.On a link with a multicast protocol (such as PIM or IGMP) enabled, the switch cannotrestore multicast data transmission after switchover until the switch receives multicastmessages (such as PIM Hello messages and IGMP general group query messages)and adds the static router port to the corresponding multicast entry. The process willcause temporary interruption of multicast data transmission. For real-time servicessuch as IPTV, the delay will cause some undesirable problems such as picture jitter.You can configure a port as a static router port to solve this problem. When the link stateswitches, the multicast data can be switched from the primary link to the secondary linkimmediately, so that the switch need not wait for multicast protocol messages and themulticast data transmission delay is avoided. Additionally, a static port never times outexcept when a link fails or the configuration is removed.II. Configuring static router portsConfigure static router ports as follows:z Enable IGMP snooping globallyz Enable multicast routing globallyz Allocate an Ethernet port to the corresponding VLANz Configure an IP address for the VLANz Enable the multicast routing protocol on the VLAN interfacez Bring the Ethernet port to the up stateFollow these steps to configure static router ports:
