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Ping Failure with IPv6 Virtual Interfaces on Broadcom BCM57414 Adapters

  • 1.  Ping Failure with IPv6 Virtual Interfaces on Broadcom BCM57414 Adapters

    Posted 19 days ago

    Hi,

        I am currently facing an issue that appears to be specific to Broadcom Ethernet Adapters (BCM57414 NetXtreme-E 10Gb/25Gb) on the host system. This issue does not manifest when using QLogic or Mellanox cards. The setup involves Intel E810 Ethernet Adapters on the target system and Broadcom BCM57414 adapters on the host.

    Issue Scenario:

    • Create 8 virtual interfaces with IPv6 addressing on both the host and the target.
    • From the host, initiate ping to the corresponding IPv6 address on the target.
    • Delete & recreate the target's virtual interface before each ping attempt using the Linux "ip link" commands .

    In this setup, the ping succeeds only when the number of virtual interfaces on the host is fewer than 5.

    Example of cmds to create 1 virtual interface setup in both host & target:

                   Recreate the virtual interface on the target using:

                   // Eth6.5

                   # ip link set dev eth6.5 down

                   # ip link delete eth6.5

                   # ip link add link eth6 name eth6.5 type vlan id 5

                   # ip -6 addr add 2100:4510:5::42/64 dev eth6.5

                   # ip link set dev eth6.5 up

    Create virtual interface on the host using nmcli:

    # nmcli connection add type vlan con-name eno5np0.5 ifname eno5np0.5 vlan.parent eno5np0 vlan.id 5

    # nmcli connection modify "eno5np0.5" ipv6.method "manual" ipv6.addresses "2100:4510:5::5/64"

    # nmcli connection up 'eno5np0.5'

    So, i have done some analysis and found that 

    • The target receives ICMPv6 Echo Requests from the host.
    • In response, the target sends Neighbor Solicitation messages to resolve the MAC address of the host.
    • However, the host does not respond with Neighbor Advertisement messages, resulting in ping failures.

    I have also observed that ping succeeds in the following conditions:

    • When the neighbor cache on the host is cleared everytime before a ping is issued. Or
    • When each virtual interface on the host is assigned a unique MAC address. Or
    • When the host interface is set to promiscuous mode. Or
    • When the number of virtual interfaces on the host is fewer than 5.

    I appreciate any insights regarding this behaviour.  More specifically, want to know are there any known limitations on the number of virtual interfaces that can be created when using Broadcom BCM57414 adapters?

    Host Config:

    OS         : RHEL 9.3 /9.4

    Ethernet Adapters : BCM57414 NetXtreme-E 10Gb/25Gb

    SETUP:     Enterprises Data centre