Residential VSAT experiences?

Tue Jun 23 12:59:58 UTC 2015

On Mon, Jun 22, 2015 at 10:39 PM, Nicholas Oas <nicholas.oas at gmail.com> wrote:
> Would anyone mind sharing with me their first-hand experiences with
> residential satellite internet?
>
> Right now I am evaluating HughesNet Gen4 and ViaSat Exede and I'm thinking
> specifically as a sysadmin who needs to use the uplink for work, not surf.
>
> What are your experiences with the following applications?
> -SSH, (specifically interactive CLI shell access)
> -RDP
> -SIP over SSL
> -IPSec Tunneling (should be a non-starter due to latency)
> -GRE Tunneling

Working for an satellite ISP I can give you some technical background.
We're only target enterprise/government/military customers with more
specific use cases because offering satellite based Internet to
residential customers without making them angry while being profitable
is hard. So I've no experience with HughesNet Gen4 or ViaSat Exede as
products in particular but I know the underling platforms. In general
the systems are optimized for fast browsing and VoIP from the own
operator. The modems you'll use with the mentioned services will
include all kinds of acceleration features. General acceleration of
TCP sessions to work around TCP implementation issues in combination
the the high RTT (slow start, behavior during packet loss/high jitter,
window scaling, ...) are standard for these services. The residential
services usually use additional acceleration features like HTTP
prefetching/pushing. That's usually done using a transparent HTTP
proxy which sits at the teleport analyzing all HTTP
requests/responses, download images etc. already before they are
actually requested the the end users browser. They are then pushed to
the modem which will delivery them as soon as the end user requests
them. As a result the end user doesn't have to wait another RTT for
the images etc.. Similar sniffing/spoofing acceleration options are
available for other protocols. But with end to end encryption becoming
more common these days all these transparent higher level acceleration
features of the modems, etc. no longer work. Of course you still can
do the same but you have to move the acceleration to the client
device. That's not very common yet in the satellite industry.
Regarding phone conversations our experience is that the high RTT is
not that much of an problem in practice. People recognize the delay
and wait longer before starting to talk automatically.
But the experience might vary extremely depending on the operators
config and end devices. You need corresponding QoS settings to keep
latency/jitter low and stable. For residential services the return
channel will be most likely time division multiplexed. Once the
network is congested (=profitable for the operator) you'll see the
latency go beyond 1 second more or less often without proper QoS
settings. That of course will completely break your VoIP experience.
You should expect that the operator only has corresponding QoS
settings for their own VoIP service in place. Experience with third
party services might suck due to that. Another issue you might run
into are some VoIP phones. Some of them only support very small jitter
buffers (<10ms) which might cause problems.

IPsec tunneling, GRE tunneling etc. should work perfectly fine unless
it's intentionally filtered. But as soon as you do
tunneling/encryption you should expect that you byepass any
acceleration feature or high priority QoS rule.

Besides that both products you mentioned AFAIK are using Ka-Band spot
beam satellites. There's probably roughly one beam per US state.
Assuming 200 MHz per beam that translate to roughly to a maximum of
600-700 Mbit/s downstream capacity shared by all customers in that
beam (one state). Upstream is probably designed for half of that. This
grouping of customers also makes a simple experience comparison
difficult as your experience will heavily depend on the congestion
level in your beam. From other similar services we already know that
at the launch new customers are happy (always getting the maximum
speed) but as the network fills up they get angry due to bad
performance during peak times.

I really wouldn't recommend a sysadmin to use a geo stationary
satellite based connection for your daily work unless there's no other
way - simply due to the latency. You'll notice a significant
productivity impact.

Best Regards,
Frederik Kriewitz