HowTo Configure a 3rd Party Switch Connected to a Pair of Mellanox MLAG Switches

Version 2

    This post discusses the connectivity and configuration of a Cisco switch that is connected to a pair of Mellanox MLAG switches.

    The reader is assumed to have knowledge in MLAG and general networking.

     

    References

     

    Setup

    Two Mellanox switches (SX1012 in the illustration below) are configured as an MLAG pair, connected with an IPL link.

    One Cisco switch (Nexus in the illustration below) is connected using two cables to the two Mellanox switches, one cable to each switch.

     

    3.png

     

     

    Overview

    • Although it is possible to set the link between the Cisco switch and the Mellanox switches as switchport access, it is recommended to set it as trunk, as in this example.
    • With respect to the MLAG pair, the Cisco switch is considered the same as any server in the network.
    • A regular port-channel should be configured on the Cisco Nexus ports connected to the Mellanox MLAG switches.

     

     

    Prerequisites

    1. Follow HowTo Configure MLAG on Mellanox Switches to configure both Mellanox SX1012 switches.

    As an example, you can use ports 11 and 12 for the IPL ports of the MLAG.

     

     

    Cisco Nexus Configuration

    1. Configure port-channel on the cisco switch

    switch (config) # interface port-channel 1

     

    2. Set the ports connected to the Mellanox switches as switchport trunk.

    switch (config) # interface ethernet 1/1

    switch (config-if) # switchport mode trunk

    switch (config-if) # interface ethernet 1/2

    switch (config-if) # switchport mode trunk

     

    3. Map the physical Ethernet port to the port channel.

    switch (config) # interface ethernet 1/1

    switch (config-if) # channel-group 1 mode active

    switch (config-if) # interface ethernet 1/2

    switch (config-if) # channel-group 1 mode active

     

    4. Add the relevant VLANs of your network - for example, VLAN 10.

    switch (config) # vlan 10

     

     

    Mellanox MLAG Interface Configuration

    1. Make sure that the MLAG switch pair is configured and enabled - see HowTo Configure MLAG on Mellanox Switches.

     

    2. Set the ports on both SX1012 systems as trunk.

    switch (config) # interface ethernet 1/1 switchport mode trunk

     

    3. Create an MLAG port channel.

    switch (config) # interface mlag-port-channel 1

     

    4. Map the physical Ethernet port on both switches to the same MLAG port channel.

    switch (config) # interface ethernet 1/1 mlag-channel-group 1 mode active

     

    5. Add the relevant VLANs of your networks - for example, VLAN 10.

    switch (config) # vlan 10