ExtremeSwitching (EXOS)

  • 1.  MLAG configuration

    Posted 10-14-2018 12:22
    Hi,
    im having a virtual lab, where i try to practice MLAG, the topology is as in the diagram



    now i have a problem and some questions regarding MLAGmy problem that MLAG doesnt come up,
    i have followed the following on both EXOS1 and EXOS2 switches
    EXOS1
    configure vlan default delete ports all
    configure vr VR-Default delete ports 1-7
    configure vr VR-Default add ports 1-7
    configure vlan default delete ports 1-7
    create vlan "ISC-VLAN"
    configure vlan ISC-VLAN tag 10
    create vlan "VLAN20"
    configure vlan VLAN20 tag 20
    enable sharing 3 grouping 3-4 algorithm roundRobin-based lacp
    configure vlan ISC-VLAN add ports 3 tagged
    configure vlan VLAN20 add ports 3 tagged
    configure vlan ISC-VLAN ipaddress 1.1.1.1 255.255.255.252
    configure vlan VLAN20 ipaddress 10.1.20.2 255.255.255.0
    enable ipforwarding vlan VLAN20

    create mlag peer "core"
    configure mlag peer "core" ipaddress 1.1.1.2 vr VR-Default

    EXOS2
    configure vlan default delete ports all
    configure vr VR-Default delete ports 1-7
    configure vr VR-Default add ports 1-7
    configure vlan default delete ports 1-7
    create vlan "ISC-VLAN"
    configure vlan ISC-VLAN tag 10
    create vlan "VLAN20"
    configure vlan VLAN20 tag 20
    enable sharing 3 grouping 3-4 algorithm roundRobin-based lacp
    configure vlan ISC-VLAN add ports 3 tagged
    configure vlan ISC-VLAN ipaddress 1.1.1.2 255.255.255.252
    configure vlan VLAN20 ipaddress 10.1.20.3 255.255.255.0
    enable ipforwarding vlan VLAN20

    create mlag peer "core"
    configure mlag peer "core" ipaddress 1.1.1.1 vr VR-Default

    Where's the output of show mlag peer on EXOS1
    * EXOS01.131 # show mlag peer
    Multi-switch Link Aggregation Peers:

    MLAG Peer : core
    VLAN : ISC-VLAN Virtual Router : VR-Default
    Local IP Address : 1.1.1.1 Peer IP Address : 1.1.1.2
    MLAG ports : 0 Tx-Interval : 1000 ms
    Checkpoint Status : Down Peer Tx-Interval : 0 ms
    Rx-Hellos : 0 Tx-Hellos : 120768
    Rx-Checkpoint Msgs: 0 Tx-Checkpoint Msgs: 0
    Rx-Hello Errors : 0 Tx-Hello Errors : 863
    Hello Timeouts : 0 Checkpoint Errors : 0
    Up Time : N/A Peer Conn.Failures: 0
    Local MAC : 50:00:00:03:00:00 Peer MAC : None
    Config'd LACP MAC : None Current LACP MAC : 50:00:00:03:00:00
    Authentication : None


    Alternate path information: None
    and from EXOS2
    EXOS02.42 # show mlag peer
    Multi-switch Link Aggregation Peers:

    MLAG Peer : core
    VLAN : ISC-VLAN Virtual Router : VR-Default
    Local IP Address : 1.1.1.2 Peer IP Address : 1.1.1.1
    MLAG ports : 0 Tx-Interval : 1000 ms
    Checkpoint Status : Down Peer Tx-Interval : 0 ms
    Rx-Hellos : 0 Tx-Hellos : 118591
    Rx-Checkpoint Msgs: 0 Tx-Checkpoint Msgs: 0
    Rx-Hello Errors : 0 Tx-Hello Errors : 1253
    Hello Timeouts : 0 Checkpoint Errors : 0
    Up Time : N/A Peer Conn.Failures: 0
    Local MAC : 50:00:00:04:00:00 Peer MAC : None
    Config'd LACP MAC : None Current LACP MAC : 50:00:00:04:00:00
    Authentication : None

    Alternate path information: Nonejudging from the output i think that the Hello is not happening between the peers.

    can someone advice what am I doing wrong.

    also
    do we need to tag all VLANs (in this case VLAN 20 ) on ISC Ports? if not, how would the failover happen.
    Thanks
    Sulaiman


  • 2.  RE: MLAG configuration

    Posted 10-14-2018 14:08
    Hi Sulaiman,

    There is one thing for sure I would add to your config on both sides:
    enable mlag port 1 peer core id 1[/code]So you specify that your downlink port (no. 1 here) is to be considered as an element of a multi-switch terminated lag with ID of 1, where this ID has to be the same on both switches for that particular MLAG link.

    If you had this command, and there was such amount of hellos transmitted and none received, I would take a look at VLAN id (both sides the same), tagging (both sides the same) and if the port is enabled and link connected.

    You didn't add VLAN20 to your port 3 on EXOS2 by the way, and to any other ports that have to share this data VLAN.

    As on each port, on your ISC you could have some single untagged VLAN, but I think it's better to have clear picture with only tagged VLANs everywhere except access ports. And if you ask, do we need to span all data VLANs across peer-peer connection, the answer is yes. If MLAG peers have to pretend being a single device from a downstream device perspective, they should be able to pass those VLANs' between them in case of unicast traffic.

    On how the failover works, you can read thoroughly in EXOS User Guide, it's a really nice lecture not only for this topic. :)
    https://documentation.extremenetworks.com/exos_22.5/EXOS_User_Guide_22_5.pdf
    In brief:
    - MLAG switches prevent broadcast, multicast and unknown unicast coming from a downstream device to their peer, without that we would have a broadcast storm;
    - if single peer link/lag fails, blocking filter is taken down.

    Hope that helps,
    Tomasz



  • 3.  RE: MLAG configuration

    Posted 10-15-2018 06:55
    thanks for the reply,
    i have tried to configure the same on both Core EXOS1 and EXOS2
    here's a sample
    EXOS1: enable mlag port 1 peer "core" id 1
    EXOS2: enable mlag port 1 peer "core" id 1
    and the lag on downstream device

    enable sharing 1 grouping 1-2 algorithm roundRobin-based lacp

    do i need to tag ISC VLAN on that trunk?

    but usually we when i configure mlag kind of technology, like Dell VLT and cisco vPC, once we config is complete, without configuring the MLAG ports, (which are connected to downstream device) the status shows as up.

    is it different on EXOS?
    sorry if that seem naive, but im totally new to Extreme switches.
    Thanks
    Sulaiman



  • 4.  RE: MLAG configuration

    Posted 10-15-2018 06:55
    In my experience, when you're using LACP on the downstream ports, you still need to create a "sharing" group on each switch containing just one member (the one from the local switch). It's a little weird, but it seems to work.



  • 5.  RE: MLAG configuration

    Posted 10-15-2018 06:55
    Good point, when LACP is running on one side, it expects it be running on the other end.


  • 6.  RE: MLAG configuration

    Posted 10-15-2018 11:41
    The MLAG peer is shown as up even without any MLAG ports configured, just as with e.g. Dell VLT or Cisco vPC.

    The configuration looks OK.

    Did you test IP connectivity across the ISC?


  • 7.  RE: MLAG configuration

    Posted 10-16-2018 16:24
    So, verify that your Physical is up on ports 3 and 4. Verify the sharing is up on 3 and 4. If both are up then I would look to change the algorithm of the share to L2 or L3 and see if the MLAG comes up.

    Look at this as a reference:
    https://gtacknowledge.extremenetworks.com/articles/How_To/How-to-configure-MLAG-in-Extreme-switches