Wednesday 8 April 2015

Help for setting up a btnet leased line with a Cisco 2921 and FSP150CP

I recently helped a client who had a btnet leased line installed - BT turned up to the property, installed a Cisco 2921 router connected to a FSP150CP showed the client it was working with their laptop and promptly left with a few notes as to IP address and mask.

The client was a little confused to say the least! I was asked to help - and many other people may find themselves in a similar situation.

Firstly, you will need a few things:

  • IPv4 Network Address (You should have been sent this in advance, if not ask the engineer installing)
  • IPv4 Network Mask (same as above)
  • Something to take care of NAT and act as a firewall (we used a Draytek Vigor 2830)
To work out your range of external IPs, you can use your network address and mask with a subnet calculator (such as http://www.subnet-calculator.com/)

The following has been created using the following IP addresses - you will need to enter your own instead for this to work! Be sure to change them and use the subnet calculator above if you need your entire range.

If our Network address is: 81.14.198.192 and our mask is 255.255.255.248 then our range is: 81.14.198.193 - 81.14.198.198 (to work this out, enter the address and select the mask on the calculator - the bottom then gives you the range)

In this instance, BT put their Gateway device on 81.14.198.193 (the first available IP from the available range) therefore you have 194 to 198 as external IP addresses to use.

So how do you get your kit working?

Get your firewall/router and plug a cable from the GE 0/1 port on the Cisco into the "WAN" port on your router. Ensure that this is a WAN port that takes a network cable and not a telephone one, as this is for ADSL or VDSL.

Now login to your own router, and set it a static IP address for Internet Access. The routers IP can be any of the addresses from 81.14.198.194 to 81.14.198.198. Enter the subnet address as: 255.255.255.248 and the Gateway address as 81.14.198.193.

And that should be it - there are a lot more things that can be done but these are the basics to get things working.

I hope it helps someone


On a more personal note, I did all of the above correctly for my latest setup of this equipment but couldn't get any data to move in or out of the router. Long story short, BT managed to assign the gateway device (The Cisco) with the range IP instead of the first available IP address! After a few calls to BT it was sorted and everything magically started working.

11 comments:

  1. Hi Des,

    I'm in this same predicament, Btnet 10/10 EFM installed the technician showed one of my staff his laptop on the net and that was it. When I got to the office tried to get everything working and it was useless.

    I'm gonna do what you say, need a good wireless router first, is there anything you suggest in the SoHo market or should I try something more business orientated. My main use is sending data over a streaming encoder. Thanks for your help.

    James

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  2. Hi James,

    I'm quite the Draytek Vigor fans for SMEs - therefore depending on your requirements this would be something i'd recommend (the 2860 for example).

    I hope you get it sorted

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  3. Hi

    Have a similar setup for a client but can not seem to open up certain ports for cctv web cam etc. do BT need to do this?

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    1. No, the ports will need to be opened into the router you have plugged into the Cisco router (in my example, it would be the draytek). BT do not need to do anything - if its not working, then you may have a port conflict (as an example, port 80 is often used to manage the router by default, so if your CCTV server also uses port 80 one will need to be changed). Other problems can be related to the CCTV server not having the router set as its gateway (if its manually assigned rather than DHCP)

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  4. Thank you will get on site later in the week and try.

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  5. Thank you for posting this article; I too was told that BTNET had been set-up and I was to connect it to our network with scant advice on how to do it (including being told that our router may not be compatible). Your advice on how to use the IP numbers was invaluable, after all most of us only have to do this kind of thing once or twice in our whole career.

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  7. The Cisco 2921 is a managed router. BTnet offer a wires only option where the fibre is terminated in the NTE, usually the ADVA box you have allowing the end user the option to manage their own routing. Rather than plug a router into a router could the NTE not be plugged straight into the Draytek routers WAN port using a short fibre patch cable (after going into an SFP media converter to change fibre to Ethernet cable)? We have an order in progress but have yet to advise if we want the Cisco Router which is 2k worth of kit and increased line rental to repay it. Benefits of a router connecting to another router?

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    1. Hi did you ever work out if you could just plug the draytek straight into the ADVA box rather than the Cisco option? have same issue and 2k is alot of money if not necessarily required, thanks

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  8. Thanks for posting this advice, it really helped me work out the connectivity between Draytek and BT Cisco router. Many thanks

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