provides an overview of the Tethering Detection feature.
In this release,
the Tethering Detection feature is supported only on the GGSN, HA, and P-GW.
Tethering refers to
the use of a mobile smartphone as a USB dongle/modem to provide Internet
connectivity to PC devices (laptops, PDAs, tablets, and so on) running on the
smartphone's data plan. Typically, for smartphone users, most operators have in
place an unlimited data plan, the usage of which is intended to be from the
smartphone as a mobile device. However, some subscribers use the low cost /
unlimited usage data plan to provide Internet connectivity to their laptops in
places where normal Internet connection via broadband/WiFi may be costly,
unavailable, or insecure.
Detection feature enables detection of subscriber data traffic originating from
PC devices tethered to mobile smartphones, and also provides effective
reporting to enable service providers take business decisions on how to manage
such usage and to bill subscribers accordingly. Tethering Detection is
supported for IPv4 (TCP)and IPv6 traffic flows.
The Tethering Detection feature is enabled on a per rulebase basis. The rulebase (billing plan) assigned for APN will contain the tethering detection related configuration. ECS performs tethering detection on a per flow basis for all subscribers (for whom TAC database match succeeded) using an APN in which the feature is enabled. The extent to which the detection mechanism is executed depends on the type of flow. If it is a non-TCP flow, for example UDP or ICMP, then tethering detection is not possible for the same, in releases prior to 18.2.
ECS supports various tethering detection solutions:
TTL-based tethering detection
UA-based tethering detection
OS-based tethering detection
In 18.2 and later releases, the IP-TTL based tethering detection
solution is implemented to support tethering for all IP flows - both IPv4 and
IPv6. This feature is configurable at the rulebase level and will be done for
all flows of all subscribers having IP-TTL configuration within the rulebase.
In release 18.2,
IPv6 tethering detection is supported with only TTL and UA signatures, and not
supported for OS signatures. In 18.4 and later releases, IPv6 OS-based
tethering detection is supported.
In 18.4 and later releases, IPv6 Tethering Detection is
supported for OS-based signatures. If the signature format used for IPv6 OS
based tethering detection needs to be modified, additional data must be
collected to identify fields of the new signature. The following new TCP
parameters are added to EDRs:
from the TCP SYN packet of a flow
8 bytes of
control parameters that include data offset, reserved, flags, window size,
checksum and urgent pointer from TCP SYN header
TCP options, if
they are present in TCP SYN header