On 18-May-2006, at 17:23, Mr. Siumafua Moala wrote:
Thanks for your help, ideas, suggestions, etc.
We are using SDM-300 Sat modems with a UB-530 interface board.
This has an
EI-530 interface which can be wired to V.35 standards. We have
our core
routers at the SES (only < .5 mtr away) and using Ethernet take
it to the
distribution/access network where one is 500mtrs and another is
2km. We
keep the internet traffic on a separate VLAN to distribute it.
This way you
need not have to run it into a Mux or converter... Saves you money.
We use the same setup at the moment (with 3/2 down/up) but I was
wondering if we could increase the length of the V.35 link so
we can move the router to our computer room from the earth station
for ease of maintenance, etc.
I look through the blackbox site and they had converters,
extenders, etc but with max of 2mbps.
About eight years ago, before southern cross was lit and as the
Internet in New Zealand was having one of its little growth spurts,
we landed a 10Mbit/s carrier from Intelsat 177E to an earthstation in
Carlaw Park in Auckland. The uplink was from Steel Valley in
California, which was operated by Vyvx.
I just found one of the test traces we ran, as we were testing the
carrier.
http://www.patho.gen.nz/~jabley/pix/cn_beg.gif
We used an SDM-2020 modulator in California and the corresponding
demod in Auckland, each of which presented HSSI interfaces to a cisco
router (a 7204 and a 7505, respectively). Since this was a
unidirectional US -> NZ link we had to mangle some $150 cisco cables
and loop various conductors within them to convince the routers in
each site that the interfaces were actually up.
We would have liked to avoid putting what (at the time) were
expensive routers in the earthstations, but we had great trouble
finding a good alternative: we couldn't extend them using sync telco
circuits because we kept running into sync/clocking issues: it was
(fairly obviously) next to impossible to arrange for the achieved
signal rate over the bird to match any of the available transmission
rates of any DSU we could buy.
When it came to troubleshooting transmission problems through either
earthstation, it was very handy to have a local router there to
diagnose problems. The more boxes there are between your antenna and
your router, the harder it is to know whether you need to be talking
to the uplink operator, the satellite operator, the earthstation
operator or the person providing transmission from the earthstation
back to your main site. Unless you have good, hard evidence as to
what is going on, they will all just keep pointing fingers at each
other and whistling, innocently.
So, I would say that having routers close to your antennas is a good
idea.
Joe
