Wired Intelligent Edge

 View Only
  • 1.  Difference between setting igmp static-group in igmp and igmp snooping...

    Posted Feb 11, 2022 04:18 AM
    Hi,

    I have tried to figure out whats the difference in CX6100 (10.09..) when I do either

    vlan 100
    ip igmp snooping static-group A.B.C.D

    OR

    interface vlan 100
    ip igmp static-group A.B.C.D

    I mean that while igmp snooping is swithes way to find out what kind of multicast there is in ports, is "snooping static-group" way to subscribe multicast A.B.C.D to every port which is in vlan 100?

    Regards
    -jori

    ------------------------------
    Regards
    Jori Luoto
    ------------------------------


  • 2.  RE: Difference between setting igmp static-group in igmp and igmp snooping...

    Posted Feb 14, 2022 07:40 AM
    Hi Jori,

    I haven't tested this, but the "igmp snooping static-group" should subscribe not all the ports, which are members of this VLAN, but only the ports that are interested (IGMP join) for this multicast traffic - actually this is the purpose of IGMP snooping (to limit the broadcast and forward traffic to interested devices only/ at L2). IGMP is L3 protocol and IGMP snooping is like L2 optimization for L3 IGMP, that is why both are configured under different context configuration (SVI/VLAN).

    ------------------------------
    Stanislav Naydenov
    ------------------------------



  • 3.  RE: Difference between setting igmp static-group in igmp and igmp snooping...

    Posted Feb 15, 2022 08:01 AM
    Hi Stanislav,

    Thanks for your reply!

    Then "vlan 100 ip igmp snooping static-group A.B.C.D"  doesn't make sense because if there is already enabled igmp snooping in vlan it should keep track of subscriptions in different ports inside vlan. I haven't got time to test this either but I'm kind of hoping to to see static subscription of given multicast to all ports inside given vlan.

    Anyway in AOS version of switch there is only one context to use to make static subscriptions and it is "interface vlan 100 ip igmp static-group A.B.C.D"

    As far as I know IGMP works on L2/L3 levels where snoopin/querier is acting L2 level (current switching gear uses also L3 when switch has firmware, like AOS-CX, which understands L3 addressing schema) and PIM/BGP/mrouter acts purely in L3 level routing multicast between subnets.

    (I would appreciate to have better explanations into CLI manual what these configuration entries really do!)

    ------------------------------
    Jori Luoto
    ------------------------------



  • 4.  RE: Difference between setting igmp static-group in igmp and igmp snooping...

    Posted Feb 19, 2022 08:11 AM
    While reading ACSP study guide there is some more information to this question...

    Vlan interface's (L2)  igmp snooping acting in local switch finding out local multicast receivers and transmitters.
    Interface vlan (L3 if switch has ip address...) utilizes igmp querier functions.

    Still I don't know in which configuration context I should use if I want to subscribe 224.0.1.129 (PTP clocking data) statically into switch and flood it to all ports in vlan (haven't got time to create test setup for this)

    ------------------------------
    Jori Luoto
    ------------------------------



  • 5.  RE: Difference between setting igmp static-group in igmp and igmp snooping...

    Posted Feb 25, 2022 07:58 AM
    Hi Jori,

    In general I believe both commands will serve you let's say the same way - they are available because of different use cases (depends if you are using the switch as L2 or L3). The other community users may correct me if I'm wrong. 

    For your particular case it looks like PTP is not supported for 6100 switches, that is why the config is missing in the guides for this particular model (it is in the "Fundamental Guide"). That is why I will point you to the guide of the 6300/6400 switches (which can serve as transparent clocks only), where you will find information regarding PTP config and the use cases (for PTP configs both commands mentioned by you are used if the transparent clock is L2 or L3 - to force a static igmp joins):
    https://www.arubanetworks.com/techdocs/AOS-CX/10.08/PDF/fundamentals_6300-6400.pdf

    As there is no PTP support for 6100 switches, I am not sure if you are even able to use the device as Transparent Clock (probably what you are trying to achieve).

    ------------------------------
    Stanislav Naydenov
    ------------------------------



  • 6.  RE: Difference between setting igmp static-group in igmp and igmp snooping...

    Posted Mar 01, 2022 07:32 AM
    Hi

    PTP transparency is whole different thing and there is no way to get IGMP to calculate PTP packets resident time and add that time to PTP packets delay field just before pass it onto next switch or end user device (like some DECT systems)

    I was asking differences between two same/different configuration parameter in igmp snooping and I still would like to know what is the difference (it would be first time I'm seeing two different config strings for same functionality)

    I did test difference between L2 and L3 interfaces and I did not noticed any differences there while testing with one switch and:
    "vlan x
    ip igmp snooping static-group A.B.C.D"

    OR

    "interface vlan x
    ip igmp static-group A.B.C.D"

    Both interfaces gave same result (flooding A.B.C.D multicast to all member ports)

    ------------------------------
    Jori Luoto
    ------------------------------