Connecting servers to the core/distribution switches

[KESHAV METHI]

                   Hi,

We are using CISCO Catalyst 6500 switches as collapsed core/distribution switches (2 layer architecture). I want to connect approximatly 10 application servers to the network.

Can I connect the servers directly to the catalyst 6500 switches using WS-X6148E-GE-TX line cards? The other option is to use access switchs and then connect the servers to the catalyst 6500 through access switch(Catalyst 3750).

Please advise which option is better.

[Edison Ortiz]

Yes, you can connect them directly to the 6148E module.

[Durga Prasad M.S]

Hi Kesav,
Connecting servers directly would give you better performance as the core switch would have better backplane and hence better performance.
Of course if you are using a high end server farm switch with 10 gig type uplinks to core, that is also a good solution.
Otherwise you are creating a bottleneck in your network as the uplink cable might be just 1gbps and so many servers connect to the rest of the network through a smaller pipe.

Rgds/dp
Sent from Cisco Technical Support iPad App

[Joseph W. Doherty]

Disclaimer

The  Author of this posting offers the information contained within this  posting without consideration and with the reader's understanding that  there's no implied or expressed suitability or fitness for any purpose.  Information provided is for informational purposes only and should not  be construed as rendering professional advice of any kind. Usage of this  posting's information is solely at reader's own risk.

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In  no event shall Author be liable for any damages whatsoever (including,  without limitation, damages for loss of use, data or profit) arising out  of the use or inability to use the posting's information even if Author  has been advised of the possibility of such damage.

Posting

We are using CISCO Catalyst 6500 switches as collapsed core/distribution switches (2 layer architecture). I want to connect approximatly 10 application servers to the network. 
Can I connect the servers directly to the catalyst 6500 switches using WS-X6148E-GE-TX line cards? The other option is to use access switchs and then connect the servers to the catalyst 6500 through access switch(Catalyst 3750).
Please advise which option is better.

Can you?  Probably.

Should you?  Insufficient information.

The 6148 is a closet line card.  It doesn't well support busy ports, often the case with server ports.  It's also a classic bus card, which depending what else is in your chassis, could degrade performance.

It would be helpful if you describe what's exactly in your 6500 now, what particular 3750 model is your alternative solution, whether it's stacked, and if so, with what, and how the 3750 connects to the 6500.

[KESHAV METHI]

Thank you all for the quick response.

Joseph,

The catalyst 6500 is serving as collapsed core/distribution switch. we are connecting approximately 15 no. of access switches each with 10G uplink connections to the 6500.

Now we want to connect some servers such as CCTV server, WLAN controllers, data base server, VoIP servers, IPTV servers etc.

The alternate solution is to use Catalyst 3750-X series stackable switches with 2X10G connection to the 6500.

I hope the above information helps.

Regards,

Keshav

[Joseph W. Doherty · Accepted solution]

Disclaimer

The   Author of this posting offers the information contained within this   posting without consideration and with the reader's understanding that   there's no implied or expressed suitability or fitness for any purpose.   Information provided is for informational purposes only and should not   be construed as rendering professional advice of any kind. Usage of  this  posting's information is solely at reader's own risk.

Liability Disclaimer

In   no event shall Author be liable for any damages whatsoever (including,   without limitation, damages for loss of use, data or profit) arising  out  of the use or inability to use the posting's information even if  Author  has been advised of the possibility of such damage.

Posting

It helps a little, but there's still insufficient information as you haven't described what exactly your 6500 is currently populated with.

For example, if you're going to have 15 pairs of 10g links on the 6500, this implies some 6700 series 10g cards, all of which are fabric only cards.  A classic bus card and a fabric card can't even directly communicate, they have to bounce data transfers through the supervisor.  Additionally, any classic bus card precludes the whole chassis from running in compact mode, halving (or more) the supervisor's PPS rate.  Lastly, as Leo mentions, you'll want to avoid sharing ASICs on a 6148 cards (I recall it's one ASIC per 8 ports).

Basically, again, you can use a 6148 but it can be very degrading to overall performance of the 6500, and since this is your core device, is that acceptable?

The reason I asked what else is in the chassis, if you already have any other classic bus cards in the chassis, adding another classic bus cards won't degrade the whole chassis further.

Personally, working with gig and 10g ports, in a distribution/core role, I recommend preserving compact mode.  Additionally, a 3750-X may also perform better connected to a 6500 via dual 10g links than devices connected using a 6148 as it has 20 Gbps vs. 16 Gbps bandwidth.

PS:

BTW, if you had a 6724/6748 line card, that would be the best way to connect the servers to the 6500.

[Leo Laohoo]

I'll agree with Joseph's comment.  If there's only 10 servers, then (I guess) a 6148 is sufficient (thereby agreeing with Edison's post)

HOWEVER, I would caution about "bunching" up all the servers' interface into one ASIC.  If you can spread them around then you can, just about, get away with it.