Trying to understand this features, correct me if im wrong in this:
If the AutoRP feature is enabled in a Sparse Mode only network, you should use AutoRP Listener so the 220.127.116.11 and 18.104.22.168 groups are able to work as Dense Groups.
But, if AutoRP is enabled in a Sparse-Dense network, you should use NO DM Fallback, not to make it work, but to avoid that other groups (besides .39 and .49) work in Dense mode. Is this right? if you configure no ip dm-fallback, would the AutorRP groups still work?
I've seen people configuring no "ip dm-fallback" in conjuction with "autorp listener", and I just dont see the point.
this an alternate way to solve the problem of propagation in dense mode of groups 22.214.171.124 and 126.96.36.199
ip pim autorp listener
To cause IP multicast traffic for the two Auto-RP groups 188.8.131.52 and 184.108.40.206 to be Protocol Independent Multicast (PIM) dense mode flooded across interfaces operating in PIM sparse mode, use the ip pim autorp listener command in global configuration mode. To disable this feature, use the no form of this command.
according to command reference user notes for ip pim dm-fallback:
Use this command to prevent a router from falling back into PIM-DM when the RP becomes unavailable. This command also causes the router to block all multicast traffic for groups not specifically configured with an RP.
When IP multicast is used in mission-critical networks, you should avoid the use of PIM-DM. PIM makes the determination as to whether a multicast group operates in PIM-DM or PIM sparse-dense mode based solely on the existence of RP information in the group-to-RP mapping cache. If Auto-RP is configured or a bootstrap router (BSR) is used to distribute RP information, there is a risk that RP information can be lost if all RPs, Auto-RP, or the BSR for a group fails due to network congestion. This failure can lead to the network either partially or fully falling back into PIM-DM.
If a network falls back into PIM-DM, dense mode flooding will occur. Routers that lose RP information will switch all existing states into dense mode and any new states that must be created for the failed group will be created in dense mode.
PIM dense mode fallback is enabled. That is, a multicast group in the absence of rendezvous point (RP) information will fall to dense mode, regardless of the interface mode configuration.
if no ip pim fall-back blocks autoRP as you see in your tests is doing something that is not documented in the notes.
After waiting a little while, it looks like "no ip pim dm-fallback" did not blocked AutoRP groups.
But I'm curious about what you said "doing something that is not documented"
If the group has no RP (and groups 220.127.116.11, 18.104.22.168 dont have an RP at first) and DM Fallback is enabled, this two groups should work as Dense Mode.. but if DM Fallback is disabled (like in my test), then it should be blocked, right?
Like you said:
"PIM dense mode fallback is enabled. That is, a multicast group in the absence of rendezvous point (RP) information will fall to dense mode, regardless of the interface mode configuration."
So the opposite is true? if it is NO enabled, then it wont fall to dense.. so should it be blocked?
Hi everyone, I would like to thank you in advance for any help you can provide a newcomer like myself!
Im studying the 100-105 book by Odom and am currently on the topic of Port security. I purchased a used 2960 and I'm trying to follow a...
While deploying a number of 18xx/2802/3802 model access points (APs), which run AP-COS as their operating platform. It can be observed on some occasions that while many of their access points were able to join the fabric WLC withou...
I am going to design and build an LAN network under a tunnel underground with long distance between the switches.
I will have 2 Catalyst switches and 8 Industrial IE3000, and they will be connected with fiber.
For now I am planning on use Layer-2 s...