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QFX5120-32C Port Group?

  • 1.  QFX5120-32C Port Group?

    Posted 02-09-2021 23:18
    I am reviewing the QFX5120-32C.
    Regarding Port Setting, I have seen a document with the following contents.


    To configure ports 4 through 7 to operate as 25-Gigabit Ethernet ports, you must configure port 4 to operate as 25-Gigabit Ethernet ports.

    [edit chassis fpc 0 pic 0]
    user@switch# set port 4 speed 25g

    Q1. Does it mean that 0-3, 4-7, 8-11 ... are operated at the same channelize speed as one port group?
    Q2. If so, does the non-channelize port (40G/100G) work regardless of the port group?

    I can't find the exact document.
    Please Help me.

  • 2.  RE: QFX5120-32C Port Group?

    Posted 02-10-2021 00:17

    From the document

    Supported Port Speeds

    • 40-Gbps and 100-Gbps (non-channelized mode)

    • 10-Gbps, 25-Gbps, and 50-Gbps (channelized mode)

    So all the 32 ports will operate as 100G or 40G depending on the individual port speed setting.

    For the channelized mode you have to use the breakout cable. So each port can be configured in the channelized mode.
    For example:

    if you want to channelized port 4 it will result into 4 ports each supporting 25G speed.
    et-0/0/4---------> et-0/0/4:0, et-0/0/4:1, et-0/0/4:2, et-0/0/4:3

    Hope this helps

  • 3.  RE: QFX5120-32C Port Group?

    Posted 02-10-2021 00:25
    Thank you for your reply.
    I understood your words.
    However, what I want to know is that when entering the "set port 0 speed 25g" config for channelized et-0/0/0,  et-0/0/0 to et-0/0/3 are operated as 25G channelized.
    In the document I saw above, I understood that 4 ports are a group.

  • 4.  RE: QFX5120-32C Port Group?

    Posted 02-10-2021 02:16
    What's confusing you is the fact that you are looking on port speed for SFP/SFP28 ports (meaning QFX5120-48Y or EX4650-48Y). There a group of 4 physical ports can either run 4 x 25G or 4 x 1/10G.  For QFX5120-32C you can choose to channelize every QSFP28 port individually.

    This hint is that the documentation talks about SFP/SFP28 ports, where QFX5120-32C only have QSFP/QSFP28 ports (plus 2 x SFP+...).

    The following steps describe how to channelize SFP/SFP28 block of ports. You can configure the SFP and SFP28 port speeds only per quad (group of 4 ports) and not individually. All ports operate at a single speed within the quad. For instance, if you configure ports 8 through 11 to operate as 25-Gigabit Ethernet ports and you insert a 10G SFP+ transceiver in port 10, an interface is not created for this port.

    Jonas Hauge Klingenberg - Juniper Ambassador