PIM SM + IGMP snooping suitability test

PIM SM + IGMP snooping suitability test test topology

Figure 1

Bootstrap

The BOOTSTRAP protocol is used to designate and announce the RP, the BOOTSTRAP protocol ensures that the entire network chooses a unique BSR (boot router) through Bootstrap messages, BSR collects the RP information in the network and floods all PIM routers in the PIM domain; C-RP learned about BSR, By sending candidate-rp-advertisement messages to BSR via unicast, BSR translates all C-RP priorities and associated multicast uncorrupted set into Rp-set, flooding the entire PIM through Bootstrap.

IGMP snooping

IGMP snooping manages and controls the forwarding of multicast data packets at the data link layer by listening for multicast protocol messages sent between the three-layer multicast device and the user host to maintain the outgoing interface information of the group broadcast text.

Question and answer questions 1:BSR how to elect, can seize?

A: BSR can preempt. When router A is configured as C-BSR, a 130s boot timer is started and the bootstrap message is monitored. If there is no competition in the network C-BSR, router A after the 130s boot timer expires, become BSR, at 60s intervals to the network to announce bootstrap messages; If there is a competition C-BSR in the network, router A will compare priority (priority equality compared IP address greater priority), if the priority is low, Router A resets the boot timer to continue listening if priority high Router a becomes BSR after the 130s boot timer expires. Visible high-priority C-BSR can preempt, preemption delay of 130s.

Problem 2:1 huiju switch on VLAN 100 on the IGMP snooping, downlink link1, link2 link layer redundancy, ask IGMP snooping can you sense link failover?

A: You can adjust the IGMP parameters to make IGMP snooping fast-sensing link switching. Let's go back to the IGMP and IGMP snooping working mechanism:
IGMP Overview:
When a host needs to join a multicast group, the Membership report message is sent to the router, and the router sends the corresponding multicast traffic to the interface that receives the message, and the router periodically (default 60s) sends the general Query rotation subnet to determine if there are Group members or no group members in the network. , the host will reply to the Membership Report message notification Router after receiving the general Query.
Description of IGMP snooping:
　　　　　　　　　　
Fig. 2 Fig. 3

Multicast frames are flooded on the data link layer by default, 2, non-group members are not joined to the multicast group, but the switch still floods multicast data to non-group members, resulting in a waste of link bandwidth. IGMP snooping manages and controls the forwarding of multicast data packets at the data link layer by monitoring the Membership report message and the general Query message at the switch level.
IGMP snooping Port Type:

type	Description
Dynamic routing Port	Receive the Port of General Query
Dynamic member ports	Receive Port for Membership report

IGMP Snoopnig maintains a multicast group (multicast IP) corresponding to the dynamic member port, as follows:

The switch forwards the multicast packets based on this corresponding relational table.
Adjust IGMP parameters for fast switching:
1 members of the group send Membership report to join the multicast group 224.1.1.1, via LINK1 transmission, Huiju switch IGMP snooping will add 224.1.1.1 in the multicast group G0/0/1 Dynamic member port, when Link1 fails, Link2 enabled, IGMP snooping removes G0/0/1 from the dynamic member port group, but does not automatically join the G0/0/2, where group members cannot access the multicast data; After a certain time, Huiju vlanif100 sends the general Query, The group member responds to membership report, IGMP snooping updates, and team members can re-receive multicast data.
Therefore, you can speed up the IGMP snooping switching speed by changing the query period of the small router general query.
Note: Eth-trunk logically belongs to a port, and failover is transparent to IGMP snooping.

PIM SM + IGMP snooping suitability test