Justifying Gig Ethernet... 4

[Max5Pier]

We just bought a bundle of cisco 2950 switches with 2 1000Mbps ports. The original idea was to connect the servers on the 1000Mbps ports and to connect the clients at 100Mbps. The Servers are running Win2K and the clients WinXP. Sounds logical, does it?

But now,some architect wants us to use a speed of 100Mbps on the server and 10mbps on the clients. The main reason being that we don't need that speed and that the Gig technology is not mature enough.

I'm looking for arguments to convince him that since we already have the infrastructure to use the Gig speed we should use it and not go back in time... Any ideas anyone???

Thx

 

[manarth]

if you have a huge number of clients, present that as a reason to maintain 100 Mbps on the clients.

Management understand $$$
Calculate the cost difference on the clients between 10 M and 100 M. ($1 per PC? if that? how many NICs can you find today that CAN'T do 100 Mbps?!)
Then point out the cost if you had to upgrade later: cost of new card + min 5 minutes per PC (assuming no driver installation required) + downtime....


The server argument's harder....if you don't need the speed you can't argue on that ground.... you could try comparing the initial cost of 1000 MBps with the initial cost of 100 Mbps plus a subsequent upgrade to 1000 Mbps.

as for the argument that gig technology isn't "mature" enough - fah.

<marc> i wonder what will happen if i press this...[ul][li]please give feedback on what works / what doesn't[/li][li]need some help? how to get a better answer: faq581-3339[/li][/ul]

 

[manarth]

plus also - you may want to try forum655: Overcoming Obstacles Getting My Work Done!

good luck
<marc>

 

[bcastner]

With switches there is no reason not to run 100-Full Duplex between the client and switch. None.

I will grant that the hard disks are not going to throw onto the switches to the clients anything close to 1 Gigabyte. That is not the point. The switches are likely store-and-forward, and you want to upload the fast device to the slower device as fast as possible so that the fast device can use its threads on something else.

If anything, it recommends that the RAM buffer on the switches be sized appropriately. But as a general recommendation on its face the advice you were given is neither sound nor desirable.

 

[jimbopalmer]

Very few 10 meg cards do full duplex, so even in a fully switched environment you will get collisions at 10/half, needlessly slowing down the servers (and the clients).

Getting all the clients to full duplex (at any speed) will reduce the load on the servers, 100/full is the most common way to acheive that.

I confess to being skeptical that you can saturate a gig ethernet on a PC, but I suspect you can produce more work with a gig card than 100 meg, and isn't that what you got your servers to do?



I tried to remain child-like, all I acheived was childish.

 

[jimbopalmer]

In a more general sense, I got gig E as a BACKBONE technology, to connect the buildings at my site. Through some oversite on the standards committees there is no singlemode 100meg standard or a multimode 100 that goes over 2km, I had singlemode FDDI in place to go 19,000 feet (5.8 km) and 100 meg ethernet was not a choice for that leg. Only recently have we been adding servers at gig.

I tried to remain child-like, all I acheived was childish.

 

[gunthnp]

5.8km thats a little long how does it does it stay up and how the speed jimbopalmer

and on the server side I am still a fan of useing mutlnics at 100mbp over 1000 single card I have gotten better through put with this setup using 2-4 full deplex

gunthnp

 

[Max5Pier]

Wouldn't the 2 Gig ports on the switches justify their use ? The company already paid for these Gig ports.

I guess the question now is, will I get better performance with one Gig Nic or with two 100Meg Nic ? Obviously, the second option is more robust, but how often does a nic dies...

 

[bcastner]

Sunk costs are a good argument, once the costs are sunk. In other words, they do not justify the intial purchase, they justify their use once there.

Using two adapters on the servers, load balanced, and providing redundancy, is a good argument. Yuu have high bandwidth, load balancing and a fallback if one should die on you.

There is little argument you could have a satisfactory current result without the fiber ports now. But there should be little argument that the investment now in the higher capacity option is a short-run break-even financial decision, and a medium-to-long term decision that in technical terms would be advisable.

 

[jimbopalmer]

ginthnp the fiber has been up since 1992, and has been gig since 1998, it has a very low error count and is trouble free (which is good as my back up plan is 5.5 meg wireless, which the users WILL notice if I ever have to use it) thankfully it is a pretty straight path with few splices.

I tried to remain child-like, all I acheived was childish.