# Can I register an ABP device that has fixed DevAddr, NwkSKey and AppSKey? **URL:** \ **Category:** End Devices (Nodes)\ **Created:** [October 21, 2016, 11:50am UTC](https://www.thethingsnetwork.org/forum/t/can-i-register-an-abp-device-that-has-fixed-devaddr-nwkskey-and-appskey/3831 "2016-10-21T11:50:53Z")\ **Posts on this page:** 1\ **Showing post:** 17
**Author:** ![arjanvanb](https://www.thethingsnetwork.org/forum/user_avatar/www.thethingsnetwork.org/arjanvanb/32/46626_2.png) [@arjanvanb](https://www.thethingsnetwork.org/forum/u/arjanvanb)\ **Post date:** [February 27, 2017, 6:42pm UTC](https://www.thethingsnetwork.org/forum/t/can-i-register-an-abp-device-that-has-fixed-devaddr-nwkskey-and-appskey/3831/17 "2017-02-27T18:42:38Z")
It’s not possible to register just any `DevAdr`, as it [includes a network identifier](https://lora-alliance.org/sites/default/files/2018-05/lorawan1_0_2-20161012_1398_1.pdf#page=32): > The most significant 7 bits are used as network identifier (NwkID) to separate addresses of territorially overlapping networks of different network operators and to remedy roaming issues. The least significant 25 bits, the network address (NwkAddr) of the end-device, can be arbitrarily assigned by the network manager. > > […] > > The seven LSB of the NetID are called NwkID and match the seven MSB of the short address of an end-device as described before. The documentation on [Addressing and Activation](https://www.thethingsnetwork.org/docs/lorawan/addressing.html) explains some more: > The Things Network Foundation has received a 7-bit device address prefix from the LoRa Alliance. This means that all TTN device addresses will start with `0x26` or `0x27` (although addresses that start with these might also belong to other networks with the same prefix). (TTN currently uses a NetID of `0x000013`, hence its NwkID is the 7 bits binary `%0010011`. As hexadecimal `0x26` is binary `%00100110`, and `0x27` is `%00100111`, both indeed start with the 7 bits NwkID.) Also, the TTN-assigned DevAddr uses some more encoding for internal routing. From the same documentation: > Within TTN, we assign device address prefixes to “regions” (for example, device addresses in the `eu` region start with `0x2601`). Within a region, the NetworkServer is responsible for assigning device addresses. We are using prefixes here too for different device classes (for example, [ABP](https://www.thethingsnetwork.org/docs/lorawan/addressing.html#activation-by-personalization-abp) devices in the `eu` region start with `0x26011`) or to shard devices over different servers. (This indeed yields less than 12 bits within a region and class to generate a DevAddr, yielding only 4,096 unique values within such region and class. This is not a problem as a DevAddr [is not unique](https://www.thethingsnetwork.org/forum/t/how-does-a-network-know-a-received-packet-is-for-them/2735/2).) @htdvisser wrote in Slack, about just copying some existing `DevAdr` into TTN Console: > No, that won’t be possible in the public network > > We route data based on the NetID that was assigned to us by the LoRa Alliance > > Devices with a DevAddr that does not match our NetID, are (according to the LoRaWAN spec) part of another network > > If a manufacturer puts fixed DevAddr/NwkSKey/AppSKey in a device without giving the customer the ability to change those, they either don’t know what they’re doing or they don’t really care about the customer or they try to create some kind of lock-in to their own network. > > And if if the NwkSKey/AppSKey is `2B7E151628AED2A6ABF7158809CF4F3C` I would think twice before buying the device. And about the test NetID `01`/`02`: > We don’t issue DevAddresses for `00` / `01` but it is possible to “force-register” a device with such address (not in the console, only with `ttnctl`) > > For such devices, we can still route data > > But uplink for anything else than `00` / `01` / `26` / `27` will just be dropped before it’s even considered by the backend > > Or routed to a roaming partner when roaming is added to LoRaWAN and supported by us --- _[View the full topic](https://www.thethingsnetwork.org/forum/t/can-i-register-an-abp-device-that-has-fixed-devaddr-nwkskey-and-appskey/3831)._