nanog mailing list archives

Re: Starlink routing


From: Eric Kuhnke <eric.kuhnke () gmail com>
Date: Mon, 23 Jan 2023 15:43:03 -0800

I think it's useful to clarify terminology - the starlink antenna unit
itself is the CPE.  With my v1 starlink terminal you can plug literally
anything into the PoE injector that is a 1500 MTU 1000BaseT DHCP client and
it'll get an address and a default route out to the internet. All of the
smarts happen in the antenna unit/phased array unit which also has its own
fairly capable embedded CPU/RAM and routing capability.

The starlink *indoor* CPE, the home wifi router itself ,is a very basic
thing that looks like something derived from a Taiwan ODM 802.11ac home
router OpenWRT reference design with a custom firmware load.Or similar. If
you've seen a teardown of one they're very simple.

With the v2 rectangular terminals it's similar but you need a cable adapter
to go from the proprietary starlink cable to indoor unit, and additionally
the indoor CPE unit also serves as the PoE injector.

In some other ISP type environments you might be expecting the indoor unit
to be the CPE, such as what you'd get with a Comcast DOCSIS3.0 all-in-one
modem+coax interface+router+wifi device attached to some coax coming in
through a wall.



On Mon, Jan 23, 2023 at 3:36 PM Michael Thomas <mike () mtcc com> wrote:


On 1/23/23 3:14 PM, Eric Kuhnke wrote:
The original and traditional high-cost way of how this is done for
MEO/LEO is exemplified by an o3b terminal, which has two active
motorized tracking antennas. The antenna presently in use for the
satellite that is overhead follows it until it's descending towards
the horizon, while at the same time the second antenna aims itself at
where the next 'rising' satellite is predicted to appear at the
opposite horizon, and forms a link to it. Make-before-break. If anyone
has seen photographs in their marketing material/videos of the Oneweb
beta test earth stations in Alaska they are operating using the same
general concept.

Oneweb has clearly positioned their market focus for telecoms and ISPs
and large enterprise end users, because their CPE equipment is
considerably larger, expensive and more power hungry. The beta test
sites I've seen installed on top of a telecom equipment shelter occupy
an area approximately 8 feet long x 4 feet wide including radomes and
mounting.

I'm trying to understand this so sorry if this comes off dumb. So does
the base station mediate all handoffs where the CPE is told when/what to
handoff? Or does the CPE have some part in it (other than receiving the
handoff)? Does the CPE accept control traffic (L2?) from any bird? Are
there cases where the CPE needs to de-dup packets due to handoffs?

This is pretty fascinating stuff.

Mike



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