How would you route two separate server rooms (switches)?

M

Master Blaster

[H]ard|Gawd
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Nov 23, 2006
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Here on site we already have two separate server closets. One room contains three Brocade Gigabit 48-port switches, the other four Brocade Gigabit 48-port switches. The tie-in from between the rooms is a Cat 6 line - there are four of those. Currently, the switches in each closet are cascading down.


I'd like some suggestions please in regards to connectivity between the two rooms.

Should I daisy in the last switch in the 1st room to the first switch in the 2nd room, and cascade the switches? This would mean i'm only using one tie-in between the two rooms.

Or should I use a 1:1 switch tie-in (since I have four lines between the server rooms)? I'm aware I won't be able to have a direct 1:1, so one of the switches in room one would have to feed two switches in room two.

Additional Info:
These switches do have fiber ports, but they are not being used for the daisy chaining. This is something we might use in the future, barring cost of the fiber connect for each switch. We only run Cat 6/5e - right now bandwidth is not an issue. The site will eventually house roughly 200+ devices.

Any insight or tips would be quite helpful.

TIA!
 
You select one switch as the core. You connect to that all the other switches, and any high-bandwidth devices (file servers, etc...)
 
Depends how you are stacking them. Are you using stack cables? or just cat6 cables to link the switches?
 
k1pp3r said:
Depends how you are stacking them. Are you using stack cables? or just cat6 cables to link the switches?
Click to expand...

cat 6 lines. I know it's not the most preferable of scenarios. honestly, and I'd have to go double check, i do not think these switches have a dedicated stacking port.
 
Master Blaster,

As Jeff1 said - designate one of your switches as the "core" switch. Patch your servers into that, then link each of the other switches back to the "core" - 1:6. It'll minimize latency, and if one of the inter-closet cables fails, you can then just link that switch back to one of the others in the closet.

H.
 
Haitch said:
Master Blaster,

As Jeff1 said - designate one of your switches as the "core" switch. Patch your servers into that, then link each of the other switches back to the "core" - 1:6. It'll minimize latency, and if one of the inter-closet cables fails, you can then just link that switch back to one of the others in the closet.

H.
Click to expand...

Thanks, I was laying in bed last night thinking about this.

Much appreciations to everyone.
 
also depends on where your bottlenecks are... and what your data usages are...

this is assuming all data is going everywhere... which is never the case (unless you've got like a cluster of servers or something)
 
Can you homerun everything in the server room where you have the multiple switches? If so, use a centrally located switch for distribution and send a single connection to each switch, otherwise, you'll have to deal with RSTP to prevent loops if you diversify the uplinks between the two rooms.
 
definately bond the 4x cat6 into etherchannel between closets.
Spanning tree would disable the other 3 otherwise.

As mentioned. pick one switch in each closet to be distribution switch.
port 44-48 between your two closet distribution switches.

Have the remaining 2 acess layer switches uplink to it.
Might bond 2 or more cables to keep up with demand.

Move any chatty boxes like servers onto distribution switch.

You can now aggregate 4gig of bandwidth between closets;
shared among the 3 switches, rather than limit to 1gb each.
 
^ this. 4x etherchannel between closets and then 2x etherchannel from each distribution switch to the access switches. If you can afford the port space...
 
high-availability-1.jpg


I have deployed, managed and fixed this model many times both in labs and production. This is one of the best ways to build your L2/L3 network.
 
Would there be any reason not to use link aggregation/bonding other than if you have the port resources to do it? It almost seems that you'd want to do this by default then...?
 
Not really... you'd think most people would do that, but I see it quite often that people only link switches with one crosslink.
 
/usr/home said:
Not really... you'd think most people would do that, but I see it quite often that people only link switches with one crosslink.
Click to expand...

Yeah, I see this way too often at a lot of sites, if you can run one cable, then you might as well run two, or 4 ;)



The one thing to watch for when you deploying 802.3ad (Link Aggregation) is what factors you use to actually balance the traffic across the individual links in the port channel. In order to avoid traffic polarizing to a single link I would ensure that you load balance L2 traffic by using source-destination MAC address and L3 traffic using source-destination IP addresses. In a client server environment this should allow all links in the portchannel to receive roughly equal traffic loads.
 
l3thal6 said:
Yeah, I see this way too often at a lot of sites, if you can run one cable, then you might as well run two, or 4 ;)



The one thing to watch for when you deploying 802.3ad (Link Aggregation) is what factors you use to actually balance the traffic across the individual links in the port channel. In order to avoid traffic polarizing to a single link I would ensure that you load balance L2 traffic by using source-destination MAC address and L3 traffic using source-destination IP addresses. In a client server environment this should allow all links in the portchannel to receive roughly equal traffic loads.
Click to expand...

I've already spoken to our switch vendor, Brocade, whom confirmed that they already load balance by default.
 
I spent too much time on my vacation troubleshooting a bad ethernet cable.

Then yesterday of all days a port on a switch died. The port that uplinks to the other switch of all ports.

Please don't depend on a single cable.
 
l3thal6, how many access computers would be typical for the model depicted in the diagram? You have 12 showing, but do you really need 14 servers?
 
acewolf said:
l3thal6, how many access computers would be typical for the model depicted in the diagram? You have 12 showing, but do you really need 14 servers?
Click to expand...

Those are access SWITCHES. AKA links to desktops, printers, workstations, etc. If each of those switches are 48 port switches, you could have up to 576 devices on that network.
 
Yes, that model is basically the way Cisco recommends building a LAN. It is incredibly scalable and can easily support LARGE numbers of users.
 
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