Take the 2-minute tour ×
Server Fault is a question and answer site for professional system and network administrators. It's 100% free, no registration required.

I just started as the network admin at this company a month ago and inherited this infrastructure. enter image description here

(Router should be labeled 2921, not 2920).

Link to see image full size: http://i.imgur.com/quqFNAB.png

Within the next month or so I'm going to be splitting everything into about 8 VLAN's based on departments. Hence there is going to be a lot of inter-subnet traffic, requiring the data to traverse a layer 3 device. The VLAN's will be port based if that matters. The company moves quite a bit of data as they do design and 3d design as well as programming.

My plan is to leave the existing switches as distribution layer switches and have them all connect to one layer 3 core switch, each with 10GB fiber, and then have that core switch connected to the router for WAN traffic with 1GB Ethernet. (We don't move too much data over the WAN).

My question is whether this is a good idea, and whether I should just scrap the idea of a ~$5,000 core switch and just let the Cisco 2921 Router handle the inter-vlan traffic and add fiber modules to it to connect with the switches.

share|improve this question
2  
Even if you are going the rip/replace/upgrade route, you should gather metrics/data to support your findings. Find out if they really need what you are proposing, especially being the new guy. –  TheCleaner Mar 19 '13 at 17:25
1  
I don't suppose the NetGear switches can do any kind of routing? The 2921 is not a small router, but even Cisco says its only useful up to 250mb/s (on a good day). –  cpt_fink Mar 20 '13 at 4:56

2 Answers 2

up vote 3 down vote accepted

Within the next month or so I'm going to be splitting everything into about 8 VLAN's based on departments. Hence there is going to be a lot of inter-subnet traffic, requiring the data to traverse a layer 3 device. The VLAN's will be port based if that matters. The company moves quite a bit of data as they do design and 3d design as well as programming.

I would really question your need to have this many VLANs on a network this small. Unless you have very specific reasons for requiring separate VLANS for each department it sounds like you adding a great deal of complexity without much (perceived) benefit. Sometimes we have to resist to urge to be overly clever.

My plan is to leave the existing switches as distribution layer switches and have them all connect to one layer 3 core switch, each with 10GB fiber, and then have that core switch connected to the router for WAN traffic with 1GB Ethernet. (We don't move too much data over the WAN).

A core switch is a good idea but two core switches are better. In an ideal world all of your network paths would N+1 and this would include the core switch. You can then connect all of your distribution switches to your core switches, and your existing Catalyst 2921 to them. Again, unless you have a specific need for 10Gbps connections between your core switch and your distribution switches - I'd look at spending your $5000 dollars on two smaller switches to fulfill the roll of a network core.

You should also endeavor to link your new office switch directly to the core and not cascade it through an existing distribution switch. Again, this is just good network hygiene. You don't want the loss of one switch to effect all of the switches that are downstream of it.

And finally, unless you very attached to the idea of a core switch, you might be better of not installing a core switch/s and spending that budget on upgrading your existing Netgear switches to something that is fully managed. I realize this sounds like contradictory advice but which option is best is largely dependent on things I don't know, like possibility for future growth, available budget, acceptable network downtime, bandwidth usage, and so on.

share|improve this answer
    
I agree that perhaps I don't need that many VLAN's and will maybe get it down to four. I feel like we will need that 10GB connection because of the amount of raw video and data that is being passed through the network. The 2921 is a Router, not a Catalyst switch. Yes perhaps I didn't make it clear that the switch on the new side will also connect to the proposed core switch with fiber. I agree I would have preferred CISCO switches but the "Director of I.T." (really a programmer with limited I.T. experience) is attached to these switches. (Netgear gs752txs for reference) –  Copy Run Start Mar 19 '13 at 16:59
    
So I guess my followup question is, how much data can that Cisco 2921 Router handle? And is it feasible to just add SFP+ modules to it and connect the switches to the router directly and let the router handle the intervlan traffic. –  Copy Run Start Mar 19 '13 at 17:01
1  
From looking, I didn't see any 10GB Fiber modules for the 2921, it can do 48 GB ports, but no 10GB ports. If you're seriously attached to 10GB, I'd say the L3 core switch is a necessity. I'd bet tons of serious routed traffic will make the 2921 pretty unhappy also. –  NickW Mar 19 '13 at 17:05
1  
I'd bet money they don't, but not 5,000 dollars... maybe have a look at some of the other names out there, Arista, Supermicro, Huawei.. –  NickW Mar 19 '13 at 17:22
1  
The problem you'll run into is that the SFP+ fiber interfaces that will work with a Cisco switch may end up topping 5k all by themselves. Even skipping the SFP+ modules, a simple 10Gb netgear would cost more than that. I don't think you can get there from here. You'll have to either live with multiple 1Gb uplinks, or continue to daisy chain the switches. –  scottm32768 Mar 19 '13 at 17:38

Since you asked about router performance... these are numbers under ideal conditions, but I've found this PDF helps compare apples-to-apples as far as router capabilities.

http://www.cisco.com/web/partners/downloads/765/tools/quickreference/routerperformance.pdf

share|improve this answer

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.