Justifcation for keeping a layer 2 network homogenous

mochaaddict

Hello network minded folks,

I am getting static from finance and hoping someone can give me a little advice. What reasons would you give them to justify keeping your switches as just one brand(cisco, juniper, brocade, etc).

We use cisco on the switch side so i told them i can't stack other brands with the current equipment we have. That evidently isn't a valid reason for them.

I am just wondering if anyone has experienced issues keeping a newtwork stable and optimized when you have mixed brands.
I don't know if brand necessarily have stp, qos, or others issue between each other.

thx for any comments.

mocha

joehalford01

I would justify by pointing out your training and expertise, yes, you don't want to mix brands because you're not trained in them, that's a valid reason. There is a hidden cost in your time troubleshooting and learning another system. Present it to them with hard numbers, your time, training time, training material on several other brands; layout the reasoning. Don't approach it from a defensive angle, approach it as though you are willing to do whatever it takes to work within their framework; as long as they meet your requirements. I have no problem telling the higher ups that I will continue using "system x" to save money, but here are the reasons we should not be doing things this way. Ultimately, the decision is up to them, all you can do is work with them and hopefully get them to realize they may not be saving money (or maybe you'll realize it is a good idea, who knows).

mochaaddict wrote: »

Hello network minded folks,

I am getting static from finance and hoping someone can give me a little advice. What reasons would you give them to justify keeping your switches as just one brand(cisco, juniper, brocade, etc).

We use cisco on the switch side so i told them i can't stack other brands with the current equipment we have. That evidently isn't a valid reason for them.

I am just wondering if anyone has experienced issues keeping a newtwork stable and optimized when you have mixed brands.
I don't know if brand necessarily have stp, qos, or others issue between each other.

thx for any comments.

mocha

mochaaddict

Thanks Joe.

Although I would prefer to keep a standard, the "hidden cost in support time" might justify $$ for training.

mocha

unclerico

I've got Cisco, Juniper, and Extreme at my HQ (used to have Nortel in there as well). Obviously when talking layer 2 you speak of the spanning-tree devil! Mixing anything with Cisco will require you to either change the spanning-tree mode to MST from PVST+ or you must really understand how PVST+ will interact with MST. Also, have a full understanding of how to properly design your spanning-tree topology and how many instances you'll need to run. Be very careful to plan your VLAN usage ahead of time especially when dealing with MST because adding a VLAN after your MSTIs have converged can have disastrous consequences.

On a side note, what business is it of finance which switches you run? Do you get to query them on which financials package they run?

Daniel333

Why would training be a hidden cost? Staple the cost of a week long brand X bootcamp right along with brand X's price. Make sure it non-negociable.

it_consultant

Someone probably noticed the Cisco markup on networking equipment. This one might be hard to get around. I regularly see a mix of Dell, HP, and Cisco switches and everything works fine. My ISP uses Foundry switches and Cisco optical networking equipment with Ad Tran routers and they make it work without issue. I would caution you against using logic like "I know how Ciscos work therefore we should use Cisco" because you begin to look like an expendable line item, there are a lot of people who can work on ProCurve and Ciscos without complaining. My canned response with things like this is: "I don't really actually care as long as the hardware is from a reputable source with good support like Brocade, HP, Cisco, or Juniper". The cost difference is really only applicable to HP since they are cheaper, and Pro Curves are fantastic switches.

Forsaken_GA

The main reason to not homogenize is due to compatibility issues. Not everything is 100% standards compliant (go ahead, try and make a Force10 switch talk to a Cisco switch using MST, see what happens).

As long as your network doesn't have feature requirements that require you to stay with one vendor, you can usually intermix without issue, assuming the other vendors gear is within the performance parameters you need.

Just make absolutely positively certain the gear will play nice with each other. Most reputable vendors have labs where you can test your setup, or will loan you a unit for testing. If they're not willing to do either of those, tell the money guys that while you don't object, you're not entirely certain the gear is interoperable, despite the vendors claims, and for you to sign off on the purchase, you'd need to validate the new gears ability to integrate into the current environment, otherwise you risk making a purchase with nothing gained for it. If that doesn't put the fear into the money guys, you were screwed before you opened your mouth anyway.