Swicth Topology-Failover vs Performance

[koslyr000]

I want to connect a mid-platform (2 Web Servers , 2 Database-Servers, 1  SAN) to my enterprise network where exists three Cisco Switches.

For the moment i have two main topologies to choose to implement.

The first one has an inter-link between the Switches in order to provide a redundancy path.

At the second topology there is not redundancy at Switch level, but  there is an additional link (upgrade bandwidth via LACP) towards upper aggregation  Switch.

Which of these two topologies seems to be better according to yours opinion and experience?

At the second topology is it possible to arise connectivity problems due  to two-way paths of each web-server to the two Switches?

[Mohamed Sobair]

Hello,

I would Go with Option (1) indeed, since it provides more redundant solution with the inter-switch link. plus if you look at the throughput requirement, you will find that all the servers and upsream links doesnt reach 1 Gig Capacity and they are limited with Fastethernet, So having a 2 Gig aggregated link to the uplink Switch doesnt offer any value since also the upper switch uplink is limited to 1 Gig.

Your Second question about the connectivity issue with dual homed Servers, I beleive it wont be a problem if you operate your NIC Teaming in an (Active/Standby) Scenario. Active/Active NIC teaming will not be an option here and will not work, since you are connecting the servers to two different 2960 Switches. therfore , Active/Standby is the best option and provides the required redundancy for the Web Servers, However as I said, Option (1) overall is your best option.

Regards,

Mohamed

[Marwan ALshawi]

To add to the nice post from Mohamed

First topology may be consider as better option from topology two as you have some servers single homed and uplink failure of a 2960 can lead to a complete isolation to the servers co necked to it if you go with topology 2

However with topology 1 you to make sure that the inter switch link is in stp blocking state and the upstream switch is the root bridge

For better design you might loom at stacking the 2960s to form one logical switch where you can dual home your servers in active/standby or active/active. NIC also eliminate the reliance on STP if your HW support it

http://www.cisco.com/en/US/prod/collateral/switches/ps5718/ps6406/white_paper_c11-578928.html

Hope this helps

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