Request for Service, Tier 2 agent/supervisor or higher

field supervisor---schedule technician sooner medical issues

@user_35877d Just checking in. Are you in need of assistance? 

Thank you very much for reaching out to our team here with the questions on your XB10 modem. I will be happy to look further into any issues from here. I am not finding any known issue with that modem and the 10Gb LAN port with multi-switches. There is some information on the cable selections with that device. The 10Gb standard relies entirely on high-quality wiring. Do not use Cat5e. Use either Cat6, Cat6A, or Cat8 cables to prevent connection drop-offs. You also need a switch that auto-negotiates multi-gigabit speeds.

Thank you for your response.

We are using Cat6 cables for all of these tests. The same Cat6 cables achieve approximately 2.3 Gbps when the MacBook (Realtek RTL8156 2.5Gb adapter) is connected directly to the XB10, so the cables themselves do not appear to be the limiting factor.

I also tested two different unmanaged multi-gig switches (NICGIGA S100-0500T and UGREEN CM953). Both switches achieve normal multi-gig throughput in local iperf3 testing between two Macs (approximately 1.9 Gbps), confirming they negotiate and forward 2.5Gb traffic correctly.

However, when either switch is connected between the XB10 and the MacBook, Internet download speed consistently drops to approximately 1.4 Gbps.

In addition, the built-in 2.5Gb Ethernet port of a Kensington SD5000T5 dock achieves the same normal multi-gig LAN throughput in iperf3, but when connected directly to the XB10 it is limited to approximately 300 Mbps.

Could you please advise:

1. Are there any known interoperability issues or firmware updates related to the XB10's 10Gb LAN port?
2. Which unmanaged multi-gig switches have been validated with the XB10?
3. Which 2.5Gb USB Ethernet adapters or docks have been validated with the XB10 for the 2 Gbps Xfinity plan?

If helpful, I can also provide detailed test results, network topology, and iperf3 measurements.

Thank you for confirming the cables, that is the most common issue we have seen with those issues. I have not seen any information on a known interoperability issue or firmware problem with those ports. I am not finding any information on my end with specific adapters, multi-gig switches or docks that have been validated. The only information that I can find on the gig-switches is that you need multi-gig switches that auto-negotiate between 10G/5G/2.5G/1G. 

Thank you for your update.

As I understand your response:

• The XB10 is expected to operate correctly with devices that support standard Ethernet auto-negotiation (10G/5G/2.5G/1G).
• In our testing, every device in the network supports multi-gig auto-negotiation and works correctly with the other devices. This has been verified using local iperf3 measurements between Macs.
• However, whenever the XB10 is introduced into the topology, we observe reproducible performance degradation with multiple independent devices:
  • Two different unmanaged multi-gig switches from different manufacturers both reduce Internet throughput from approximately 2.3 Gbps to 1.4 Gbps.
  • The Kensington SD5000T5 2.5Gb Ethernet interface delivers normal multi-gig LAN performance, but achieves only about 300 Mbps when connected directly to the XB10.
• You also mentioned that Xfinity does not currently maintain a list of validated multi-gig switches, adapters, or docks for use with the XB10.

Based on these results, this appears to be a reproducible interoperability issue involving the XB10 and certain multi-gig Ethernet devices.

Could you please escalate this to the appropriate engineering or firmware team? If this is a known issue, are there any planned firmware updates, recommended workarounds, or a list of compatible devices that have been tested with the XB10?