WS-X4448 uplink trunk

Hi there,

As far I read on official Cisco website, the 48 ports 10.100.1000 line card WS-X4448-GB-RJ45 is made of 6 groups of 8 ports each connected to 1Gbits trunk to Supervisor.

What if I have 4 servers, so 4 ports, in the same vlan, same subnet, connected to the same group of 8 ports. Those 4 servers need to communicate at 1Gbits rate between eachother. Does the traffic goes up to the supervisor, so I would have 250mbits per server ? or the local traffic stays in the group on the local card and everybody got 1gbits ?

Thx for your answers!

Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

i will provide some input that may help you.
When you have devices in the same subnet, the switch only needs to use the CAM table to forward the traffic.  The CAM table contains the MAC address and associated port in which the MAC address is attached. So basically only L2 is used.  

6500 and 4500 series switches use centralized switching, "With centralized switching, routing, ACL, QoS, and forwarding decisions are made on the Supervisor Engine in a modular chassis"

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
i THINK packets may be sent to the supervisor plane for forwarding, i found this:

 Forwarding architecture: These modules use the central Cisco Express Forwarding engine located on the supervisor engine.
• Forwarding performance: These modules forward packets up to 30 Mpps per system and up to 15 Mpps per slot if upgraded to support distributed forwarding.

You are correct in your assumption - there is no "local switching" on that linecard, so every packet must go through the oversubscrbied 1GigE backplane connection.

If you have a 4500 and any Sup before the Sup6, and have servers that must communicate at 1GigE, then you need to put the servers into different port groups.  For example, server #1 in port 1, then shut down ports 2 through 8 with description "OVERSUBSCRIBED."  Server #2 would go into port 9, then shut down ports 10 through 16, etc.

This is a limitation of the 4500...  For the newer 4500-E and the Sup6-E, the backplane has increased from 6GigE to 24GigE.  You have a couple options:
  WS-X4624-SFP-E: 24-port SFP (pluggable) with full line-rate.  For typical server connectivity you would have to get a TX SFP (GLC-T)
  WS-X4648-RJ45-E: 24-port 10/100/1000 with 2:1 oversubscription.  For a high-traffic server, you would just connect on every other port.

It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Switches / Hubs

From novice to tech pro — start learning today.