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Rewire a network for under $15k and improve speed greatly?

Anyone have any suggestions personal or otherwise on how to improve the following situation (warning: this may be a little long to read, and remember, I am FIXING this situation I didn't create it!! :) )

We essentially have a Catalyst 2900 as the backbone of our network. We have several different devices connecting to this from Cisco Fasthub 300's to other Catalyst 2900's, to Nortel Baystack 350's, etc. Each hub/switch is uplinked directly to the Cat2900 with Cat5 wire. There are a total of 17 uplinked hub/switches to the Cat2900 and also several of our main file servers are directly connected to it as well.

Many of the switches and hubs we have in our organization are 24 ports, and several are full or close to full with client PC's. 3 of the 17 uplinked hub/switches are frame relay, T1 from ISP, and an additional frame relay.

We are looking into buying some new equipment and possibly running some fibre to replace some of the Cat 5 that is in place running from one side of our building to our main server room.

Questions:

1) Can anyone recommend a better way to work with what we have?

2) Keeping a cap of $15k or close to it, what devices would VASTLY improve our network performance, and how would they be integrated?

3) Finally, what would be someones IDEAL recommendation to present room for growth, regardless of price??

Thanks in advance,

Scott

5 REPLIES
New Member

Re: Rewire a network for under $15k and improve speed greatly?

Can you give a little more info?

Is there a Router in the picture here? i.e. is this a routed network (different subnets) or just one big flat network ? (one subnet) or is your "2900" Switch a Layer 3 (L3 model) switch? Are you running VLANS?

How many Servers, PC's, workstations, printers, etc. of each in total?

Are you running with 10 or 100 MB NIC cards? Just because switches have all ports full doesn't mean that all the bandwidth is full...

The better handle you have on your current total bandwidth, the better you can figure out whats needed. The 2900 Series as I recall had a backplane capable of handling 1.2 GB a second. If your total traffic is a big percentage of this, you may have to replace the 2900. Putting a sniifer on each segment may help you understand whats going on, or running RMON type stats, etc.

http://www.cisco.com/warp/public/614/4.html

The place to start is to sit down and draw your current network. Draw each switch/segment and logically whats on each. Then try and trace out the flow of data from each; i.e. does one group of stations access certain Servers, Apps, or WAN/Internet links? etc. You may get more bang for the buck just by relocating certain servers to certain switches, etc.

(Fiber may or may not help anything, depending upon whats going on in the core 2900)

Anonymous
N/A

Re: Rewire a network for under $15k and improve speed greatly?

More info:

Yes there are 2 routers in the picture here. Both are Cisco 3600 series. One connects our corporate site (which is the site I am questioning) to a frame relay WAN and about 45 other sites. The other 3600 connects a T1 up to our network here. Here at our corporate site, we have a dedicated Class C set up for all users, printers, etc. Each of our remote sites also has a Class C set up at it.

The backbone switch is a model 2924XL, and I am nearly certain it is not Layer3. There are NO VLAN's running here, and we have no immediate plans for any either.

The total number of servers we have is 14, mostly netware, a few NT servers as well. The number of workstations is about 85, and the number of printers is about 20. All servers and PC's use 10/100 compatible NIC's.

I guess, one question would be would a Layer3/4 capable switch, manage this traffic better than the 2924XL that does not have Layer3 capability? I have heard some schools of thought each way.

New Member

Re: Rewire a network for under $15k and improve speed greatly?

So you do have one big flat network. I think your 2924 is probably maxed out or close to it. My suggestion is to look into re-vamping your network with a Layer 3 switch, such as the 2948G-L3, at the core. It is reasonably priced, and the specs for it are much better than the 2924; for example: the 2948G-L3 has a 22 GB switching fabric vs. 3.2 for the 2924, and the 2948G-L3 can forward over 10 million PPS vs. 3 million for the 2924. The 2948G-L3 also has two slots that can handle GBIC cards (Gigabit) possibly for use say to a Server cluster switch.

Its really beyond the scope here of re-designing your network, but I think if you get a good handle on your data flows, sketch it out, you may find that splitting up your internal LAN into smaller groups (subnets) and using the Layer 3 switch to

route between them and your WAN and Internet links, that the throughput will improve dramatically. We re-designed our network that way recently (using the 2948G-L3) and found that to be the case. And we even implemented VLANs, using a separate subnet for each.

I highly recoomend sitting down with your Cisco network specialist . Have your current network well documented from the hardware and application/data flow first.

See also: http://www.cisco.com/univercd/cc/td/doc/pcat/c2948gl3.htm

http://www.cisco.com/warp/public/473/29.html

http://www.cisco.com/warp/public/cc/so/neso/lnso/cpso/gcnd_wp.htm

Anonymous
N/A

Re: Rewire a network for under $15k and improve speed greatly?

Thank you for the information thus far. It has definitely helped. One more question. After looking into the Gigabit campus network design, it is quite apparent that layer 2 switches at the access level and layer 3 switches at the distribution level are the way to go. Question is, what type of real world performance increase could you expect by swapping your backbone layer2 switch with a layer3 switch such as the 2948G?

Do you have any links that provide real world testing, or have any before/after test results from your own experience?

New Member

Re: Rewire a network for under $15k and improve speed greatly?

I'd like to tell you that we did all kinds of RMON and Sniffer traces, etc. before and after, but that wasn't the case. However, to give you an idea of what we did accomplish: We have about 1400 work stations feeding into 70 Layer 2 switches. each with their own subnet, and say 48 servers on another 2 switches. Originally we had 2 Cisco 3600 Routers, and replaced that with 1 2948G-L3. (Not counting Internet and WAN routers - core only) . We use "Port Channels" (802.1Q) to the various major subnets. Looking at the stats from the switch vs. that of the routers,

we have throughput of 1600-4500 packets per second on the main Port Channel.

That 's about 3 times the throughput that we previously got. And the 2948G isn't even breaking a sweat - thats about a 4/255 to 9/255 on the "Show Interface.." load. The network is noticeably faster from the users perspective; (and we run IPX ! The L2/L3 core with VLANS helps keep the broadcasts confined too)

I don't have any links handy on 2948G-L3 results, but they're probably out there.

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