Australian (ASX) Stock Market Forum

Online trading - is a redundant connection neccessary?

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MichaelD said:
Just further on redundancy,

You can get Dual-WAN routers which will automatically sense if an internet connection is down and then switch to the other.
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I would be very interested in this works in practice when it is down. The only way I can see this happening if it tries to access something from the net periodically (or when something is being accessed and there is a timeout it switches to the other).

The real issue I can see is with your trading program and how it works. If the server has a keepalive connection (usually HTTP connection) with your IP address then you still need to connect again (as it needs to associate the new username with the new Ip address). i.e try watching a youtube video, while it is switching I wouldn't be surprised to find the video stop downloading and for you to hit the refresh button. Security in the program is another issue if it associates your logon with an ip address.
 
aleckara said:
I would be very interested in this works in practice when it is down. The only way I can see this happening if it tries to access something from the net periodically (or when something is being accessed and there is a timeout it switches to the other).
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The Netgear router periodically does a DNS lookup via each internet connection (every 30 seconds, but it is user-definable). If this fails 4 times in a row (also user definable), it presumes the connection has failed and doesn't route through it any more, although it does keep trying the DNS lookups until the connection comes back up.

aleckara said:
The real issue I can see is with your trading program and how it works. If the server has a keepalive connection (usually HTTP connection) with your IP address then you still need to connect again (as it needs to associate the new username with the new Ip address). i.e try watching a youtube video, while it is switching I wouldn't be surprised to find the video stop downloading and for you to hit the refresh button. Security in the program is another issue if it associates your logon with an ip address.
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Absolutely - no failover setup can seamlessly handover because of this, and there's no way around it - you will need to relogin in, either manually or automatically.

I guess perhaps you could have 2 computers, 2 internet connections and your trading program running logged in on both computers - if your broker allows this scenario. That'd decrease your down time to the time it takes you to switch computers.

Regardless, I still maintain that a UPS is a far more essential item than a redundant internet connection. It's just less glamorous than a dual 'net router.
 
I've got an inbuilt wireless broadband card (bigpond) and also a local wireless connection. So I use my cable connection when at home and the broadband when not at home. The broadband is pretty reliable and acts as a backup if I have problems with the cable connection. I also have a backup laptop in case the main laptop cark's it altogether.


When I was in Africa recently I traded the Australian stockmarket from a game park, by candlight, during a blackout, using battery power on my laptop, and a rented vodaphone USB broadband card. I've also pulled over beside the road halfway between Stanthorpe and Brisbane and logged in to close out some options positions after getting an SMS message on my phone alerting me to a price change. Wireless broadband is pretty cool!

I'm thinking of getting an iPhone as a backup as well.
 
MichaelD said:
Absolutely - no failover setup can seamlessly handover because of this, and there's no way around it - you will need to relogin in, either manually or automatically.
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Rubbish! It is expensive and complex to do but it CAN be done.

If you really must have the same IP address across 2 different Internet connections you'll need the cooperation of your ISP and probably need to buy business grade connections/services.

If you really want 2 different ISPs the cost & complexity goes up significantly.

Anything is possible given enough time & money, it's a basic Business Continuity Planning exercise:
- What is the cost to you of your Internet connection being down? (missed trades, missed announcements, etc?)
- How long can you handle it being down before it starts to significantly impact your business? (an hour? a day? 2 minutes? 30 seconds?)
- What is the probability of it occurring? (once a day?, once a week?)

Based on probability and $ impact you should be able to identify how much to spend on a solution.

m.
 
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