My Personal Experience of Working on 5G with Huawei

The following blogpost explains my experiences with Huawei on 5G for the UK’s largest mobile operator. I was the lead architect responsible for the IT functions for their 5G deployment. I had a relatively close working relationship with Huawei. In summary I did not see any security issues with Huawei beyond the normal human security risks that apply to all vendors. I saw a vendor with strong investments in 5G and with good case studies from existing deployments. The removal of Huawei from the acceptable list of vendors will be to the technical detriment of my previous employer. I have since left BT and now work in biomedical research. My comments here are my own and are not influenced by any other party.

Case For:

In late 2018 BT & EE took the decision to not invite Huawei to respond to our new 5G mobile core RFP. I personally believed this was a mistake, as Huawei were one of the two incumbent suppliers of EE’s 4G LTE network core. EE currently use this 4G LTE network core to support the UK’s Emergency Services Network. I always believe that BT’s fiduciary duty is towards its shareholders and Huawei had provided a reliable & secure 4G core at a competitive price. Removing Huawei from the RFP increased the migration complexity and shrank the pool of possible vendors.

In late 2018 BT & EE took the decision to not invite Huawei to respond to our new 5G mobile core RFP. I personally believed this was a mistake, as Huawei were one of the two incumbent suppliers of EE’s 4G LTE network core. EE currently use this 4G LTE network core to support the UK’s Emergency Services Network. I always believe that BT’s fiduciary duty is towards its shareholders and Huawei had provided a reliable & secure 4G core at a competitive price. Removing Huawei from the RFP increased the migration complexity and shrank the pool of possible vendors.

EE had the relevant software engineering skills to make a relevant technology assessment of any risks associated with Huawei.  EE definitely had stronger domain knowledge and technical skills as GCHQ. However, since the acquisition of EE by BT those skills have started to leave the business. BT has been off-shoring key technical roles: preferring to keep its ‘business architects’ on-shore, and to move their technical skills off-shore. This has had an impact that there is now a shortage of on-shore technical skills within BT relating to 5G. 

Huawei have invested very strongly in 5G technologies as was evident from previous demos of their technologies I have seen. Their reference case scale is also incredibly impressive: China Telecom are deploying one hundred thousand 5G masts. The equivalent in the UK, would be 5000 masts by the end 2020, and that would be across all four operators. All UK deployments of 5G could have benefitted from this 5G technical domain knowledge sharing.

Case Against:

One argument I have heard is around a 5G security access risk from the user plane accessing a backdoor into the control plane. When pressed this scenario involves a secret code being passed over the network, like a specific ‘secret’ telephone number, that opens a backdoor port into the mobile core. This is spurious for two reasons, the network implements a control plane and user plane split that makes this impossible. CUPS (control user plane split) is also one of the main architectures of 5G. The second reason is that any control to user plane integration would be network monitored and discovered by the operators. 

Telecom operators invest in their network monitoring and reporting technologies. These allow the operator to see the heath of the network and to visualise the traffic flows within the network. Access to the internet is always through Internet Peering Points to which the control plane is not connected. If there was an open connection between the control plane and an internet peering point then it would be either monitored or discovered by the mobile operator

A continual security issue is a traditional issue with an industry with so many technologies and processes originating from during the Cold War. This is an issue of spies or operatives working with direct access to the telecommunications network and having the skills to eavesdrop on communications. This will always be a risk but risks can be mitigated by appropriate processes.

Conclusion:

I do not believe the back-door theories spread by certain security experts. The architecture of 5G control user plane split makes any back-door harder to access. Any tracking issues . Human risks are always present but can be mitigated. Access to the mobile core requires vetted clearance and UK tier 2 visas for Chinese workers are for only 3 months so Huawei employees never had direct access to live systems.

What is likely to occur is that telecom operators losing technical skills will become more reliant upon the OEMs for domain knowledge. If the largest OEM is excluded then the operators will either deliver things slower or at greater cost.

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