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  • 1.  LAG (LACP) 2 links different speed failover issue

    Posted Aug 25, 2021 11:47 AM
    Edited by Qais Aug 29, 2021 04:24 AM
    Hi,,

    I am a beginner with Aruba Switches and I trying to configure dynamic LAG (LACP).
    the switches type (JL664A 6300M 24G 4SFP56 Swch) version (ArubaOS-CX Version : FL.10.07.0021)

    the scenario.
    my company has two Links from HQ to ISP MPLS, one main and the other is a backup link, the main link with the speed of 1Gbps and the second one with 100Mbps.

    I tried to configure LAG and it works but the problem is that the two links act on the switch as 1000 Mbps Links but in the real there is one of them support only 100Mbps so when I tried to configure interface speed manually 100Mpbs-Fulldublex and tried to configure the priority for LACP interfaces to use the main Link (1Gbps) in LAG as the LAG speed and the other link to be redundant Link but it works vers as what I want.

    the configuration

    interface lag 1
    no shutdown
    no routing
    vlan trunk native 1
    vlan trunk allowed 300
    lacp mode active
    lacp rate fast
    interface 1/1/1
    no shutdown
    speed 100-full
    lag 1
    lacp port-id 5
    lacp port-priority 5
    interface 1/1/2
    no shutdown
    lag 1
    lacp port-id 10
    lacp port-priority 10
     


    show commands

    show lacp interfaces



    show lag 1





    I need advice how to make the 1000Mbps Link as the primary
    Note: I tried to configure speed on the main Link as 1000Mbps for testing it denying me



  • 2.  RE: LAG (LACP) 2 links different speed failover issue

    Posted Aug 28, 2021 08:46 AM
    Edited by DP-7f7ca3 Aug 28, 2021 08:56 AM
    Hi Qais (MITF IT), a LAG - no matter if it is a Non-Protocol (called "Static") or LACP (called "Dynamic") - doesn't correctly form if media speeds of involved member physical links aren't identical (simplifying: LAG doesn't form if you aggregate a 100Mbps+1000Mbps or a 1000Mbps+100Mbps, LAG forms if you aggregate a 100Mbps+100Mbps or 1000Mbps+1000Mbps).

    That's the very basic and essential rule to form a LAG and that is independent by Switch series, Vendor or OS used, it's a requirement due by design.

    IIRC on various Link Aggregation Guides for Aruba CX Switches there is a statement about the above restriction: "Choose the same speed member interfaces while attaching to the LAG. Members with different speed than the already added member do not participate in aggregation for both static and dynamic LAG."

    Also, another ESSENTIAL requirement is that the LAG's member links are co-terminating (ending) on the same physical (or logical, if any) switch where the peer LAG with same characteristic should exist...in other terms, you can't pretend a LAG perfectly formed on one device reach a good working state IF its member links aren't co-terminating on a peer device (physical or logical - as in case of virtual switch deployment - it is)...the way you aggregate two or more links together should be the same on both ends of the link.

    Hope this clarify things a bit.

    ------------------------------
    Davide Poletto
    ------------------------------



  • 3.  RE: LAG (LACP) 2 links different speed failover issue

    Posted Aug 29, 2021 04:23 AM
    Edited by Qais Aug 29, 2021 04:28 AM
    Thanks, Davide

    I understand that the Links should be same
    but I am trying to use the LAG not for expanding the bandwidth, for my scenario the main reason for using it as Link failover

    ٍSince I couldn't use LAG for my scenario could you advise me please if there is another thing I can use to make failover between two links (1000Mbps as the main ) (100Mbps as backup)


    Thanks



    Original Message


  • 4.  RE: LAG (LACP) 2 links different speed failover issue

    Posted Aug 30, 2021 12:06 AM
    Hi,

    From my point of view, you have two options:

    1. if the link need to be a l2 link you are stuck with Spanning Tree
    2. If your link can be a L3 link, and I assume for the connection to your ISP it can, you can work with multi-path routing. I would create two transfer networks to the ISP router and would set different costs for the link (if not set automatically due to the different speeds). If the link with 1Gbps fails it should automatically use the route for the 100Mbps link.

    ------------------------------
    -------------------------------------------------------------------------------
    Florian Baaske
    -------------------------------------------------------------------------------
    Any opinions expressed here are solely my own and not necessarily that of Hewlett Packard Enterprise or Aruba Networks.
    -------------------------------------------------------------------------------
    Also visit the AirHeads Youtube Channel:
    https://www.youtube.com/channel/UCFJCnuXFGfEbwEzfcgU_ERQ
    -------------------------------------------------------------------------------
    Feel free to visit my personal Blog
    https://www.flomain.de
    ------------------------------

    Original Message


  • 5.  RE: LAG (LACP) 2 links different speed failover issue

    Posted Aug 30, 2021 03:24 AM
    Edited by DP-7f7ca3 Aug 30, 2021 09:48 AM
    Hi! I agree with Florian, given your scenario you have either one solution or the other (to let a properly configured Spanning Tree feature doing its duty or playing with routing metrics/distances on route(s) of last resort).

    It would be interesting to understand, since you weren't so clear about that, what peer devices your Aruba 6300M switch is connected with...given the Partner's System ID (for the lag1) it looks like - if I'm not mistaken with reported Actor/Partner MAC Addresses - you're playing with another Aruba switch, potentially...and this looks strange because one would think that you're trying to connect your Aruba 6300M directly to ISPs' Routers (ISP Router A: WAN A - LAN A 100Mbps, ISP Router B: WAN B - LAN B 1Gbps) and you want to achieve some sort of links balancing or links failover and you're trying to connect to another Aruba switch.

    Another way is to use Multi-WAN Firewall(s) (it will act as single/redundant Next Hop Gateway for your LAN devices to reach external networks) between your switching infrastructure and your ISPs' Routers, it's a way to move upward your requirement and let the Firewall to perform WAN Links Failover and/or WAN Links Load Balancing, doing so a Transit VLAN - as suggested by Florian above - will continue to be a good approach.

    ------------------------------
    Davide Poletto
    ------------------------------

    Original Message


  • 6.  RE: LAG (LACP) 2 links different speed failover issue

    Posted May 18, 2025 05:30 AM

    Sorry to revive this old thread, but it seems that your statement is not accurate :

    That's the very basic and essential rule to form a LAG and that is independent by Switch series, Vendor or OS used, it's a requirement due by design.

    It seems that some equipments do explicitly support LAG between links with different speeds :

    • Aruba AP-575 :
      Connecting the AP-575 to your PoE compatible network switch or router through either its 2.5G or 1G Ethernet ports allows you to transfer data and power over a single cable. The two ports may also be combined using link aggregation for increased connectivity speeds with compatible devices.
    • Some Nokia routers and switches :

    Nokia routers support mixing ports of different speeds in a single LAG using either port-weight-speed or hash-weight. See section LAG port hash-weight for details related to LAG port hash-weight.

    The LAG port-weight-speed command enables mixed-speed LAG and defines the lowest port speed for a member port in that LAG as well as the type of speed ports allowed when mixed in the same LAG:


        - port-weight-speed 1 supports port speed of 1GE and 10GE
        - port-weight-speed 10 supports port speed of 10GE, 40GE, and 100GE

    Combining ports of different speeds in the same LAG is supported by default and the operator does not need to use the port-weight-speed or a customized hash-weight values.

    (...)

    The different combinations of physical port speeds supported in the same LAG are:

        - 1GE and 10GE
        - 10GE, 40GE, and 100GE
        - 100GE and 400GE

    For mixed-speed LAGs:

        - Both LACP and non-LACP configurations are supported. With LACP enabled, LACP is unaware of physical port differences.
        - QoS is distributed proportionally to port-speed, unless explicitly configured not to do so (see internal-scheduler-weight-mode).
        - User data traffic is hashed proportionally to port speed when any per-flow hash is deployed.


    Original Message


  • 7.  RE: LAG (LACP) 2 links different speed failover issue

    Posted May 18, 2025 09:05 AM
    Hi, does all you wrote adhere to what IEEE 802.3ad Standard [1] and/or 802.1AX (-2008 or newer revisions) Standard declare?




    Original Message


  • 8.  RE: LAG (LACP) 2 links different speed failover issue

    Posted May 19, 2025 10:33 AM

    For the Aruba AP I don't know, they didn't specify what they use to do LAG.

    But if you take a look at the Nokia link (https://infocenter.nokia.com/public/7750SR2110R1A/index.jsp?topic=%2Fcom.nokia.Interface_Configuration_Guide_21.10.R1%2Flag_port_weight-ai9emdyn1v.html&cp=8_2_6_3_2), they state that :

    For mixed-speed LAGs, both LACP and non-LACP configurations are supported.

    AFAIK, LACP is the usual name for standards 802.3ad or 802.1AX.

    So, yes, it looks like some vendors (Nokia at least) support LACP with mixed-speed links.


    Original Message


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