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New network setup and IP Addresses

Superuser
Superuser
Posts: 2,562
Thanks: 261
Fixes: 5
Registered: 06-04-2007

New network setup and IP Addresses

Hi all

In the next few months I might be setting up a new network in my church. The network will link our 3 offices (all in the same building), plus 2 other computers and a support a VOIP system. I am thinking of setting up a linux box to act as a fileserver / Authentication Server / VPN server. From talking to the people at gradwell about the VOIP side of things, and they reckon the easiest and most reliable way is to have a public IP address for each phone (3 phones in total).

One of the computers will be acting as a webserver (so would need an IP address?) and the VPN server would need an IP address

Assuming I have not got anything wrong above (please tell me if you spot anything!) I would need 5 Public IP addresses, and set the other computers to have private IP addresses (possibly by DHCP). Does anyone know if this can be done on a standard adsl router, or would I need to fork out a fortune on a special adsl router? Anyone got any suggestions of better ways to do this?

Given I would require 5 IP addresses, I would have to ask for a block of 8, 3 of which I could not use for any other computers or phones could I? If that is right would it be better / possible to ask for a block of 16 IP Addresses as this is likely to be expanded in the near future with possibly a few more phones, a mail server and who knows what else!!!

If anyone has any suggestions or can answer any of my questions then thanks a lot in advance.


Phil
3 REPLIES
N/A

New network setup and IP Addresses

Not sure what your budget is but you could try a Cisco 837 ADSL as your internet router ( 1 public ip address ) cost 100-200 quid on ebay, a pix 501FW ( 1 public ip address ) cost 200-250 on ebay. I suspect you've been told to use public address for the phones due to problems with NAT and PAT with the VoIP signalling protocols ( H323, SIP ) that use ip address and port combinations.
You could then use the PIX to terminate the VPN ,and with the latest release it's got support for PAT and NAT for H323 and SIP via the fixup protocol on the PIX.
Another Idea would be to use your present router and just buy the PIX maybe even a new one.
Superuser
Superuser
Posts: 2,562
Thanks: 261
Fixes: 5
Registered: 06-04-2007

New network setup and IP Addresses

There currently is no budget, and I'm still in the phase of mapping everything out in my head to put a proposal together to do this. It is accepted that we do need something soon, and I tend to be the person to come up with a few solutions and justifications for the costs.

Currently there is no network. One computer has dialup, and there is one phone! We have been expanding in admin areas quite radpidly over the last year, and need to improve communications. Also as we are expanding we're running out of office spaces, so I'm kinda thinking along ways to help with people working from home, such as with VPN and VOIP.

Edit: Ooops and I should have said thank you very much for your post!

Phil
N/A

New network setup and IP Addresses

The VPN shouldn't pose many problems. I think most of the SPs now have some form of VoIP offering ( with certain restrictions i.e. who you can call ).
To set up your own VoIP network using the internet would be more problamatic. Amongst others you'd have the voice quality issue. Most home ADSL routers don't have the qeueing algorithims or the ability to mark the VoIP packets, so giving them precedence over data, for that for that you'd have to look to the likes of a Cisco. Even when your packets are marked and sent out to your ISP they'll be treated just like everyone else i.e best effort ( DSCP =0) and be mixed and lost with larger data packets. That's bad for voice quality ,VoIP can't stand delay or jitter.
That's why VoIP in the enterprise market is taking off with the newer MPLS enabled networks, that give the customer E2E quality of service. The customer just specifies what quality of service he want's to give to specific traffic, i.e VoIP = DSCP EF, traffic to www.wastingtime.com =DSCP 0.
Implemented correctly over an MPLS enabled network and you'd be hard put to tell the difference between POTS and VoIP. Get the queueing and classification wrong along with the bandwidth for the class of traffic and your stuffed.

Success


Mike