- Explain IGMP Snooping Filtering
Role 1: Bind Deny Profile (The port only denies the specific multi-cast address traffic, it can receive other traffic)
Role 2: Bind Permit Profile (The port is only permitted to receive the specific multi-cast address traffic, it cannot recieve other traffic)
Role 3: No Bind Any Profile (The port is a general port to receive the all multi-cast address traffic when the client sends out the associated IGMP report packets).
Answer: You can bind deny and permit profile at a time for any specific port
The example below shows the rules to drop or allow any multi-cast IP
Eg: You create 2 profiles and bind under port 1
- Profile 1 with group 227.1.1.1 ~ 227.1.1.100 => Type “Deny”
- Profile 2 with group 227.1.1.200 ~ 227.1.1.250 =>type “Permit”
The switch will check Profile 1 first then turn to Profile 2
The results on port 1 are shown below
+ Multicast IP: 227.1.1.1~227.1.1.100 => drop
+ Multicast IP: 227.1.1.200~227.1.1.250 => pass
+ Other Multicast IP pass under profile 1, but drop under profile 2
If you initially commanded to add profile 2 to port 1 then Profile 1, the switch will check the rule on Profile 2 first, then turn to Profile 1.
The results on port 1 are shown below
Multicast IP: 227.1.1.200~227.1.1.250 => pass, as it initially check profile 2
Other Multicast IP => drop, in this case profile 1 has no meaning - In IGMP Filtering, the “deny” behavior is “NOT to allow the port to receive the specific multicast address." But what is the “permit” behavior? Can the port only receive the specific multi-cast address? Also, when the IGMP filtering is enabled, does it mean all ports follow the filtering table? What is the port IGMP Snooping behavior if it is not bind to the profile?
For IGMP Filtering, you can config Maximum 10 Profiles, each Profile you can config Maximum 10 multicast groups.
- "Deny” means drop
- "Permit” means allow
When filtering on a specific port, it will check the Filtering Table and only allow multi-cast in its range to “Permit”. Thus, you should filter for downlink ports only.
When IGMP filtering isenabled, it will activate the global config on the switch. Once you add a specific profile to the interface, the filtering process will start. At that point, IGMP Snooping will depend on the IGMP Filtering rules for multi-cast traffic allow or drop. - I found the setting in static multicast address as "MAC address" not "IP group address". What is the reason for this?
For IGMP Snooping and MVR, the user can set the multicast IP address. The Switch will then translate to a MAC address. For static multi-cast MAC address, this is a L2 function and used in special cases when the user wants to fix this MAC to specific ports.
- Where can I configure VLAN priority?
For VLAN priority, you can configure by
- Port-based
- QinQ
- MAC-Based
- ALC
- IGMP snooping filtering
Role 1: Bind Deny profile(The port only deny the specific multicast address traffic, others can receive)
Role 2: Bind Permit profile (The port only permit to receive the specific multicast address traffic, others cannot receive)
Role 3: No bind any profile (The port is like a general port to receive the all multicast address traffic when client send out the associated the IGMP report packets).
Answer: You can bind deny and permit profile at a time for any specific port
And the example rule to drop or allow any multicast IP as below
Eg: You create 2 profile and bind under port 1
- Profile 1 with group 227.1.1.1 ~ 227.1.1.100 => Type “Deny”
- Profile 2 with group 227.1.1.200 ~ 227.1.1.250 =>type “Permit”
The SW will check Profile 1 first then turn to Profile 2
So results on port 1 as below
+ Multicast IP: 227.1.1.1~227.1.1.100 => drop
+ Multicast IP: 227.1.1.200~227.1.1.250 => pass
+ Other Multicast IP pass under profile 1, but drop under profile 2
If you have command initially add profile 2 to port 1 then Profile 1, the SW will check the rule on Profile 2 first then turn to profile 1
So results on port 1 as below
n Multicast IP: 227.1.1.200~227.1.1.250 => pass, as it initially check profile 2
n Other Multicast IP => drop, in this case profile 1 has no meaning
- IGMP Filtering
Question: I have one question about the IGMP Filtering permit behavior.
- I can understand the “deny” behavior is “NOT to allow the port to receive the specific multicast address.
- But what is the “permit” behavior? Can the port only receive the specific multicast address?
- When the IGMP filtering enable, does it mean all ports follow the filtering table? What is the port IGMP Snooping behavior if it is not bind to the profile?
Answer: For IGMP filtering, you can config Maximum 10 profiles, each Profile you can config Maximum 10 multicast groups
The type rule
“Deny” means drop
“Permit” means allow
When you filter on specific port, it will check the Filtering table and only allow multicast in range “Permit”. Thus, you should filter for downlink ports only
When IGMP filtering enabled, it will activate the global config on SW
Once you add specific profile to interface, the filtering process will start
And from now on, IGMP Snooping will depend on IGMP filtering rule for multicast traffic allow or drop
- I found the setting in static multicast address setting is used “MAC address” not “IP group address. May I know the reason?
For IGMP snooping and MVR, user can set the multicast IP address, then SW will translate to MAC address. For static multicast MAC address, this is L2 function and use in special case when user understand and want to fix this MAC to specific ports
- Is there a log when the port is disabled by the loop detection algorithm?
Yes, the switch will generate a log.
- There is a PoE function called "Start-up Time" which means the switch will conduct the auto-checking the powered device (PD) after this time. How does the switch know the PD system is ready?
Start-up Time is the time the switch will ping to the PD initially after the PD has been start-up. If the PD responds, the switch will use the Interval + Retry setting to continue the next communication. If the PD has no response, then the switch will take Action setting. The Start-up time setting can be configured from 60~300 seconds which the user can configure base on the specific PD re-booting time.
- If a new "PD" plugs into a "high" priority port, will the switch ignore the power requested? Or will the switch drop to the lower priority port?
The switch will not drop to a lower priority port at that time, it will take effect when the link is down or power is cycled.