large branch design - what switches to use?

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Feb 11th, 2010
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Hello!


Got a branch office sited in two buildings. 120 users in one, 70 in another.

I'm going to use this design:

1)Edge+distribution -  ISR 3495 (is 3845 end-of-sale?) + 2 EtherSwitch services modules (NME-16-ES-1G-P)

2)Access - 3750E-48PD in stack.


!!! All links at all layers should be >=1000 Mbit/s.


Is  this design balanced in terms of cost/efficiency(i mean by this redundancy and routing/switching performance)


Any ideas?


Tnx.



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Leo Laohoo Thu, 02/11/2010 - 02:44
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3800 is not yet end-of-sale.
Why would you put-your-eggs-in-one-basket and get NME-16 modules?  For server switches, get 3750E and stack them or a 6500 with Sup720.  If you get a 6500 with Sup720 you are just a few blades away from 10Gb uplinks to the access 3750E.

Alexander Demin Thu, 02/11/2010 - 03:21
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Well, integrated Edge and Distribution layers is recommended for large branch by cisco design guide:

http://www.cisco.com/en/US/docs/solutions/Enterprise/Branch/Design.html#wp65928

(Integrated Routing and Switching Design)


It also recommends ISR 3825/3845 for Core, 3750/4500 for Distribution and 29xx/3560/3550 for Access layer.


Questions:


1) Due to my case (120 user ports in one buiding, 70 user port in another, all ports >=1000Mbit/s) what switches to use in Access layer ?


I think this should be some switches that could be stacked. Cisco has StackWise technology that is supported only by 3750(3750-E) series.

I don't now can 24-port 3750 be stacked with 48-port 3750 switch but if it can - then:

1st building (120 user  ports) - 2 x WS-C3750G-48TS-E + 1 x WS-C3750G-24T-E - in stack

2d building (70 user ports) -  1 x WS-C3750G-48TS-E + 1 x WS-C3750G-24T-E - in stack


2) What to use at Distribution layer? Two separate switches: 3750/4500 or as etherswitch mdules integrated in ISR?

paolo bevilacqua Thu, 02/11/2010 - 03:23
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Do you need PoE ?


If not, I would use 2960G for distribution, 2 x 3750G at core. Cheap and effective.

Jon Marshall Thu, 02/11/2010 - 03:45
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26051980DAO wrote:


Hello!


Got a branch office sited in two buildings. 120 users in one, 70 in another.

I'm going to use this design:

1)Edge+distribution -  ISR 3495 (is 3845 end-of-sale?) + 2 EtherSwitch services modules (NME-16-ES-1G-P)

2)Access - 3750E-48PD in stack.


!!! All links at all layers should be >=1000 Mbit/s.


Is  this design balanced in terms of cost/efficiency(i mean by this redundancy and routing/switching performance)


Any ideas?


Tnx.




As with all design it's important to know what the requirements are. As Paolo says, do you need PoE, and to that could be added a number of other things ie. how resilient/redundant do you need each site to be, does each site have it's own servers or is there a DC or HQ central site somewhere that houses most of them.  This is very important because as Leo points out having an ISR with an integrated module could mean a failure of the ISR router could take down the entire branch site. Now if all servers are accessed over the WAN then this is not such an issue but if you have servers locally that allow your users to continue working then would you want your ISR failing to take out the LAN as well ? Obviously not, in which case it might be a better idea to have separate switches at the distribution layer.


If servers are local then another aspect is how important is the branch site in the work of the company ie. if they lose access to their servers how much of an impact does this have on the core business. If high then you would definitely want 3750 stacked or 4500 switches with dual sups/power supplies in the access-layer.


So without knowing traffic patterns and applications it's difficult to say whether it a balanced design.


Jon

Alexander Demin Thu, 02/11/2010 - 04:49
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Thanks all for your attention!


Several remarks to this design: no PoE needed, high availability is preferable, there are about 10 servers in each building, that are used locally (no access from WAN for now).

paolo bevilacqua Thu, 02/11/2010 - 05:59
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I would go with the models I've indicated above then. Use dual link to teh core so if even on 3750 dies, you're still working.

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