I need help...

[buttonprincess]

Hi, I'm a student in my first year of an IT program at a community college and we are required to design a network layout plan. I'm not quite sure how to go about doing this - we have the layout of the building, and where all the computers are located, but I'm not sure when it's best to use a switch, router, hub...etc. I'm not quite clear on what each one does, and how one would be preferred over another. I was wondering if anyone could help me with what switches, bridges, hubs, etc do, and when it is appropriate to use one.

Extra info that may be needed for you to understand the layout of the building - it has 2 floors, 3 servers, and each floor is 200x300 feet. The min. bandwith is 100Mb.

Thanks for any help in advance!!! It is greatly appreciated.

[Josef Oduwo]

Hi Lindsey,

Your question has many answers.

Where to use a hub, switch, router depends on the function you want covered. The subject is made slightly more complicated by the fact that some routers can carry out functions that were traditionally switch functions and vice versa, but lets not go there...

Speaking very generally, think a switch to a server...

Perhaps it is better for you to find out what each of those devices does and see how they fit into the network you want:

There is some good information on network design at the Cisco website (http://www.cisco.com/univercd/cc/td/doc/cisintwk/idg4/nd2001.htm#36148). Though the rest of this site is slightly advanced, you may be able to glean some info there. Otherwise here is some more information on designing a network: http://support.intel.com/support/inbusiness/sb/CS-009396.htm and an intro on planning a TCP/IP network: http://docsun.cites.uiuc.edu/sun_docs/C/solaris_9/SUNWaadm/SYSADV3/p8.html

Good luck and let us know how you go,

/oj

PS - don't forget to rate!

[drumrb0y]

*Double-post; see following entry*

[drumrb0y · Accepted solution]

As a still-green 2nd year Network Admin, I can give you my opinion in layman terms:

Your instructor wants you to keep in mind the cabling limits of CAT5, which is about 200' from the nearest device that isn't a hub; if you mount a 10/100 switch in the center of each floor, you should be fine for patch cabling to the hosts.

Devices:

- Hubs are generally going obsolete now, with switches being cheaper; traffic crossing a hub is like talking in a crowded room - all traffic from each connected host is repeated out ALL the other ports.

- Switches are more efficient in that traffic that enters one port exits only one other port, based on an internal hardware destination list in the switch; it examines packets, determines the exit port and sends it on without repeating it to the other ports. It's like turning the crowded room into a room full of doors - only two open at a time for each packet...in & out.

- Bridges are also generally obsolete now, since many switches can perform L3 bridging/routing; in a LAN environment in a single building, you probably won't need one if your core switch does L3 routing. A bridge connects two logically and physically separate networks like a router (but routers can connect more than two).

- Routers are like bridges except that they can handle multiple interfaces, not just two (see above); many switches can now route, so a core switch with L3 routing and VLANs will serve all purposes.

My personal recommendation for your building:

One 10/100MB switch in the center of each floor, preferably one that is VLAN capable (like the Cisco 3500XL or 3550); these will trunk to an L3 routing core switch via a 1GB fiber optic backbone between floors. The servers will connect directly to the core switch, preferably with 1GB Ethernet links.

I'm sure there is a CCIE out there who can do better, but that's my two cents.

Marc

[thisisshanky]

Lindsey,

To add to Marc's post,

a. As part of making a bill of materials, you will also need to do decide on what kind of cabling, patch panels etc are required for each wiring closet. Cat5/Cat5e/Cat6, any specific patch panel vendor that you want to go with, contracting a cabling company to run the cabling etc.

b. Go with atleast a 3550 (or 3750 or 3560) as the 3500XL will soon be end of support from Cisco. Depending on the number of hosts in each floor, you will need to buy multiple switches (if more than 48 per floor). 3750 switches are very useful in this situation. They can be stacked upto 9 switches to increase port density as well as ease of management. (Stackable switches are manageable via single IP)

c. Preferably put the servers in one vlan, your internet router in another and all your PCs in a third vlan (you can split further depending upon number of hosts you want to assign in each vlan). This will give you better access control on the layer 3 core by use of VLAN access-lists.

d. If moving to IP Telephony in near future, its better that you buy a Power over Ethernet enabled switch. 3550,3750, 3560 all are available in POE models, for an extra cost difference from the original ones.

[sumanthmyneni]

Hello Princess,regarding the qus. you have posted,i think you need one router and two switches.Hubs are repeaters and do not switch or route traffic.We can rule them out.You can opt for CAT5 cables.I hope you need to use VLAN technology.