Cisco Nexus gear

We recently installed a Nexus 5020 with 12 2048T Fabirc Extenders (FEX). This will become the core switching environment for our new network. These are some pretty sweet switches with some wicked cool features. Some of the nice features:

• Unified Fabirc - Allows IP and Native SAN over the same infrastructure.
  
• VMWare intergration - Allowes the creation of VM network profiles that can travel with the VM.
  
• Multi-switch Etherchannel - On the Nexus it's refered to as Virtual Port Channel (vPC)
• No Spanning Tree - Can be either a plus or minus..but for us its simplifies in our current deployment.
  

For all of the good features there are a few gotcha's that we ran into:

• FEX ports are GigE...only...don't even think of doing 10/100
• 5020 has limited GigE....16 ports are GigE the remaing 32 are 10Gig
• vPC limits the number of Etherchannel ports per FEX to ONE

One of the interesting things we ran into with this system was configuring TACACS+ for authentication. Normally it's pretty straight foreward you define TACACS servers & the key..bam you're good to go. For the nexus it's slightly different:

1. Enable TACACS on the system:

switch (config)# feature tacacs+

2. Add TACACS+ servers:

switch (config)# tacacs-server host 12.123.34.5

3. Add TACACS+ Key:

switch(config)# tacacs-server key

4. Add authentication group:

swith (config)# aaa group server tacacs+ tacplus

5. Add Server to auth group:

switch (config-tacacs+)# server 12.34.56.7

6. set AAA to use the tacplus group:

switch (config)# aaa authentication login default group tacplus

7. Log it on the tacacs server:

switch (config)# aaa accounting default group tacplus

8. Finally, this line was needed for our set-up:

(config)# aaa authentication login ascii-authentication

So far, fairly pleased with the Nexus. We aren't doing anything too cutting edge, but our set-up on the Nexus cost considerably less than a comparable 6509 configuration. Obviously, there are pros & cons to each set-up so your mileage may vary based on the requirements for your specific deployment.