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Forum Replies

  1. Hi Rene,
    Two questions:
    Can the same situation occur with HSRP if one switch is designated for vlan 20 and the other for vlan 10 ?

    You suggest "Change your network design. Use a single router or multilayer switch as the default gateway for all VLANs."
    I think the problem is that you have 2 SVIs for each VLAN not that they are on a different switch.
    If the SVI for VLAN 10 was on one switch and VLAN 20 on the other but only one SVI per vlan I think we do not get this problem. Right ?

    Thanks
    Stuart

  2. Hi Stuart,

    This situation could also occur with HSRP yes. Cisco has a good example for this:

    HSRP Assymetric Routing

    Having only one SVI per switch would solve the problem but it's not the underlying problem here :slight_smile: It's fine to have multiple SVI interfaces on your switches, if you use one switch as the default gateway for both VLANs then you wouldn't have this problem.

    Rene

  3. Hi Rene,
    I have some question. What if H1 ping to H4 vlan 10(same subnet?) ,will SW2 learn MAC from H1?

    Thank in advance

  4. Hello Ler-sak!

    If H1 and H4 are on the same subnet, then no routing will take place. That means that the frame that goes through SW1 and SW2 will have the same source MAC (H1's MAC) and destination MAC (H4's MAC) in the frame throughout the whole transmission. So, yes SW2 will learn the MAC address from H1. Actually, both switches will learn both MAC addresses.

    I hope this has been helpful!

    Laz

  5. Hi Rene,

    Thank you for the article. But I have a question. If I use SW1 multilayer switch as a gateway for all vlans, and sw2 as a L2 switch will the problem occur again? I think it will occur for the traffic from H2 to H1 because, SW2 will not learn the mac address of H1. Is it true ?If it is true, then for the design should we use just 1 multilayer switch and connect all hosts to it to avoid flooding?

    Thanks,
    Umut

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