Cellular management changes for 100g Airwall Gateway (v2.1.3 and later)

Starting in v2.1.3, the cellular management utility on the 100g Airwall Gateway (HIPswitch) no longer has an APN auto-connect feature enabled. It has been disabled on the cellular modem due to longevity and stability issues.

Prior to this change, the modem used the configured APN only as a suggestion. If it receives an alternative APN from its provisioning, or the APN is misconfigured, it will still connect without providing input to the user with some carriers and configurations. This can cause connection issues.

Solution

Enter the exact APN as what is provisioned for the SIM card as given by the cellular provider.

AES-256 CBC with HMAC SHA256

Given an MTU of 1500, the maximum plain text Overlay Ethernet frame size without fragmenting on the ciphertext underlay is 1421 bytes.

The Airwall Gateway HIP tunnel adds 79 bytes of overhead. For each frame (less than 1421 bytes), our overhead varies between 79-94 bytes.

AES-256 GCM

Given an MTU of 1500, the maximum plain text overlay Ethernet frame size without fragmenting on the ciphertext underlay is 1425 bytes.

The Airwall Gateway HIP tunnel adds 67 bytes of overhead. For each frame (less than 1425 bytes), our overhead varies between 67-78 bytes.

To allow for the HIP tunnel overhead due to encapsulation, use an MTU of 1500.