Security mode reject (UE security capabilities mismatch)

[wayne43290]

I am using nextepc to set up a 4G experimental network. I can connect to Internet with Huawei LTE dongle E3372h. But cannot accesses the network with Huawei LTE dongle E392u-12, the reject msg is as the picture below:

I use the same USIM for both dongles. Please help, thank you!

Security mode reject.zip

[brandonjlee]

What kind of LTE base station do you use?
Security mode reject may be caused by the eNodeB you use, if there is no matching EEA/EIA algorithms between EPC and eNodeB. Could you confirm what EEA/EIA algorithms are supported in your eNodeB?

Regards,
Brandon

[brandonjlee]

We found a potential problem that might be related to this issue. We'll check it and respond soon.

[acetcom]

It seems to be a problem of security capability length in security command message.

Spec(24.301. 9.9.3.36) said:

The UE security capability is a type 4 information element with a minimum length of 4 octets and a maximum length of 7 octets.
Octets 5, 6, and 7 are optional. If octet 5 is included, then also octet 6 shall be included and octet 7 may be included.

If a UE did not indicate support of any security algorithm for Gb mode, octet 7 shall not be included.
If the UE did not indicate support of any security algorithm for Iu mode and Gb mode, octets 5, 6, and 7 shall not be included.

So, we've fixed it.

Could you build a newly updated source code from the github repository?
You can find the build guide on the link

Thank you very much!

[wayne43290]

💯 Great! With the latest code (Mar 3), now I can connect to nextEPC with Huawei LTE dongle E3372h and E392u-12.
Thanks a lot :)

[acetcom]

Very Good News!

Thanks!