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Bring performance and reliability to your network with the Aruba Core, Aggregation, and Access layer switches. Discuss the latest features and functionality of the ArubaOS-Switch and ArubaOS-CX devices, and find ways to improve security across your network to bring together a mobile first solution.
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support for "jumbo" frames in Aruba CX

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  • 1.  support for "jumbo" frames in Aruba CX

    Posted Dec 31, 2020 03:21 AM
    in Aruba OS, it was enough to configure "jumbo" command under vlan to enable jumbo frames for all traffic in that vlan. I am not able to find equivalent command in Aruba CX as there are multiple places where MTU can be configured:

    1- under "interface vlan x" there is "ip mtu" command. 

    2- under "interface x/x/x" there is "mtu" and "ip mtu" commands.

    to enable jumbo frames in any vlan, is it required to configure mtu and ip mtu on all interfaces part of this vlan + L3 vlan interface?

    no single command for this?

    ------------------------------
    Ahmad Enaya
    ------------------------------


  • 2.  RE: support for "jumbo" frames in Aruba CX
    Best Answer

    Posted Jan 03, 2021 06:09 AM
    Hi,

    No, there is not single command for enable jumbo every where

    you need to enable mtu on all physical interface and ip mtu on all L3 interface (vlan or physical)

    ------------------------------
    PowerArubaSW : Powershell Module to use Aruba Switch API for Vlan, VlanPorts, LACP, LLDP...

    PowerArubaCP: Powershell Module to use ClearPass API (create NAD, Guest...)

    PowerArubaCX: Powershell Module to use ArubaCX API (get interface/vlan/ports info)..

    ACEP / ACMX #107 / ACDX #1281
    ------------------------------



  • 3.  RE: support for "jumbo" frames in Aruba CX

    Posted Jan 03, 2021 10:57 AM
    Hi Alexis,

    "you need to enable mtu on all physical interface and ip mtu on all L3 interface (vlan or physical)"

    that "and" is confusing me a bit...did you mean that - considering a simple scenario (let me say: a physical interface, non routed, operating in access or trunk mode) - just setting an MTU value at physical interface level is not enough?

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    Davide Poletto
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  • 4.  RE: support for "jumbo" frames in Aruba CX

    Posted Jan 04, 2021 04:10 AM
    Hi Davide,
    "IP MTU" command is only required for routed traffic. "MTU" command is enough for pure L2 switch.

    ------------------------------
    Vincent Giles
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  • 5.  RE: support for "jumbo" frames in Aruba CX

    Posted Jan 04, 2021 04:19 AM
    +1 with vincent about IP MTU

    ------------------------------
    PowerArubaSW : Powershell Module to use Aruba Switch API for Vlan, VlanPorts, LACP, LLDP...

    PowerArubaCP: Powershell Module to use ClearPass API (create NAD, Guest...)

    PowerArubaCX: Powershell Module to use ArubaCX API (get interface/vlan/ports info)..

    ACEP / ACMX #107 / ACDX #1281
    ------------------------------



  • 6.  RE: support for "jumbo" frames in Aruba CX

    Posted Jan 06, 2021 09:44 AM
    Hi Vincent,

    Thanks for clarifying.

    One more question just to be sure enough, let me consider a simple scenario: having one or more physical interfaces, non routed, operating in access (or trunk) mode on various VLANs AND having the IP Routing enabled (with some SVIs defined); does it mean - as I believe (I did it that way) - that MTU value should be specified (via the mtu command) both at each physical interface context level AND also (via the ip mtu command) at each VLAN interface context level OR specifying it at VLAN interface context level is enough?

    Thanks!


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



  • 7.  RE: support for "jumbo" frames in Aruba CX

    Posted Jan 06, 2021 04:04 PM
    Hi Davide,
    Both MTU on physical interface context and IP MTU on SVI must be specified to guarantee that packet will get routed for the received MTU size.
    If SVI MTU is not specified, default MTU (1500 byte) applies and if packet is received with IP packet > 1500 byte, it won't get routed.
    Hope this clarifies.

    ------------------------------
    Vincent Giles
    ------------------------------



  • 8.  RE: support for "jumbo" frames in Aruba CX

    Posted Jan 07, 2021 06:08 PM
    Hi Vincent, Thanks a lot. Perfectly clear. Davide.

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



  • 9.  RE: support for "jumbo" frames in Aruba CX

    Posted Jan 24, 2021 09:32 AM
    Hey gang,

    Just to further clarify..  

    Let's say I have 8325 with VLAN 200 for voice, 210 for WiFi, and 220 for Cameras.
    200 is 10.200.0.1/24
    210 is 10.210.0.1/24
    220 is 10.220.0.1/24

    I have SVI MTU for 210 at ~2000 (or whatever it should be for the APs to encapsulate the stuff).
    I have port 1-10 all set for trunks, MTU at ~2000, and VLANs 200,210,220 are allowed.

    Now let's say there are 3 6200 connected to port 1/2/3.
    Ports 1-5 are access vlan 210, and each port is set with mtu 2000
    Ports 6-10 are set for 802.1x for clearpass auth and are set with default mtu
    Ports 11-48 are going to be 'colorless' ports.  Do I set the MTU on all those ports to 2000?  I'm guessing yes, since the local vlan on the switch might change depending on what device is connected.  But what happens if a camera device gets vlan 220 at 2000 MTU on the access switch, and then the larger packet gets sent up to the core where it's only set to 1500?  Does the packet get dropped only if it's supposed to be routed outside of that vlan (220)?  Since the port is set for 2000MTU but the VLAN isn't, I just wonder what might happen?

    Keeping straight the SVI vs port MTU is going to be a real treat in our environment.  We're accustomed to the 2930/3100 vlan jumbo and done command to keep the MTU consistent across campus.  I can imagine that it would get very tedious for a larger campus.

    ------------------------------
    Phillip Horn
    ------------------------------



  • 10.  RE: support for "jumbo" frames in Aruba CX

    Posted Jan 26, 2021 07:05 AM
    Yes, the packet will be dropped only if routed oustide
    and if you have only one SVI with MTU 2000 is not really needed... (to configure the MTU on the SVI...)

    ------------------------------
    PowerArubaSW : Powershell Module to use Aruba Switch API for Vlan, VlanPorts, LACP, LLDP...

    PowerArubaCP: Powershell Module to use ClearPass API (create NAD, Guest...)

    PowerArubaCX: Powershell Module to use ArubaCX API (get interface/vlan/ports info)..

    ACEP / ACMX #107 / ACDX #1281
    ------------------------------



  • 11.  RE: support for "jumbo" frames in Aruba CX

    Posted Jan 04, 2021 01:46 PM
    Thank you

    ------------------------------
    Ahmad Enaya
    ------------------------------