A scenario on IP addressing

By prettypumpkin1964 ·
I need help in this scenario I need to explain IP addressing components, contrast classful and classless IP addressing. the scenario is I am an IT Administrator for a newly founded company and have been tasked with designing am IP addressing scheme and a plan for allocation and management of IP address. The company will currently have a single, physical location with approximately 145 host (computers, printers, etc.). IT plans should accommodate 50% growth in the next 2 yrs. Have to address these questions. 1- what subnet range/s should be used? - 2. should IP addresses be dynamically or statically assigned? - 3 should 1 or more network/subnets be used? and 4 If DHCP is used, should a router, firewall or windows server be utilized and why. I have never done a scenario yet and not sure how to start it and finish it, if anyone can help would be greatly appreciated.

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ip addressing

by gdeangelis In reply to A scenario on IP addressi ...

There are many factors involved in this scenario. For example, the building may lend itself to certain network designs. You may have multiple floors or a single floor. Multiple data closets or just one. You may have virtualized servers or desktops. You will want to accommodate all these into your design. 50% may seem like too much now, but realistically, 200 or 300% might be more acurate.
A simple design you can consider is 1 floor with a single data closet serving 150 users. You need:
A core network
Networks for your firewall, dmz, remote vpn clients, etc
switch mgmt network
server network
voice network
wireless network
networks for other services you have not yet identified, like security, cameras, fire, door, video, etc
You should have multiple domain servers and dhcp servers
While you can get away with using high end switches for dhcp, a couple windows servers will do the trick and give more insight when you are troubleshooting
Most systems can get along with dhcp, so that is fine, (some older systems still need host files) but there are support benefits to statically assigned addresses. In any case, you will want reserved space in these networks for your network devices, ie. vlans, redundant or clustered systems, etc.
For you design, you could use the address space using /21 ( -
Your netmask on the devices will be
Reserve the first and last 20 or so addresses in each dhcp scope for statically assigned addresses and network devices / gateway addresses. for servers-all static for pc's printers- usable for dhcp - for wireless - usable for dhcp for voip - usable for dhcp - - for future use

While you can cut back each network to a /25 giving 126 hosts per network, you may find yourself changing this sooner than expected. However, in the spirit of you question, you may need to be more true to the question, rather than planning for not needing to change things.
If you can imagine wanting multiple networks for servers in the future for security reasons, this makes sense. You may not want to lump your security camera video servers in the same network as your email server. You may want a dedicated development network. You may have remote users that don't need access to all servers. Things like that will influence your final design. Another recommendation would be to leave for network usage. Then make for your access. This can be carved up as above, for pc's, for voip and so on. You can also go with smaller chunks if you are planning multiple data closets. /22 would give - with a/24 network for pc,s voip, other then floor 2 -
In any case, your design needs to be flexible enough to handle massive change without needing a complete overhaul. If you have 50 pc's per network now and you allow for 254 and you have separate networks already in place for voip, wireless and 4 other networks that can be carved into smaller networks as needed, you will have enough to go around without redesigning anything for a long time.
There are lots of pages available on classless and classful addressing.
Please let me know if this was helpful or if you need anything else. Remember that using 10. address space is not necessary, you can use 172.29.x or 192.168.x as well. It is just a little more flexible if there is expansion down the road.

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by sheune15 In reply to ip addressing

a little complex but sounds helpful. thanks. am doing the same project...

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