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HPE7-A04 · Question #78

You have VSX Pairs of CX 10000 48-Port 25G SFP28 Switches (Front/Port to Back/Power airflow) with 2 DACs for ISL. What is the maximum interface speed for each DAC connection?

The correct answer is D. 100G DAC. On the CX 10000 48-Port 25G SFP28 switch, the ISL (Inter-Switch Link) ports used for VSX pairing are the high-speed QSFP28 uplink ports, which operate at 100G - making D correct. The "25G SFP28" in the switch name refers to the 48 access/downlink ports, not the uplink/ISL…

Designing Data Center Network Architectures

Question

You have VSX Pairs of CX 10000 48-Port 25G SFP28 Switches (Front/Port to Back/Power airflow) with 2 DACs for ISL. What is the maximum interface speed for each DAC connection?

Options

  • A10
  • B50
  • C25
  • D100G DAC

How the community answered

(17 responses)
  • A
    6% (1)
  • B
    6% (1)
  • D
    88% (15)

Explanation

On the CX 10000 48-Port 25G SFP28 switch, the ISL (Inter-Switch Link) ports used for VSX pairing are the high-speed QSFP28 uplink ports, which operate at 100G - making D correct. The "25G SFP28" in the switch name refers to the 48 access/downlink ports, not the uplink/ISL ports; this is a common trap that makes C (25G) tempting but wrong. Options A (10G) and B (50G) are not standard or supported speeds for the ISL connections on these switches - 10G is too slow for modern ISL, and 50G is not a valid DAC speed in this context.

Memory tip: Separate the port types mentally - "48-Port 25G" describes access ports, while ISL always rides the uplink ports, which step up to 100G. When you see a switch model with mixed port speeds, ISL uses the fastest available interface.

Topics

#CX 10000#VSX ISL#DAC speed#hardware specs

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