Qos is not only for prioritization, but for buffering and queueing on the ports,what about buffering and queueing on the core? aren't these things only available if QoS is enabled?

If so, why is no better to have these things than not have them?

What about layer 2 switching on the access to core vs lay 3 routing from access to dist to core, it seems to me the former is going to be much faster than the latter, especially if there is buffering and queueing on the core.

I do not see the benefit to having  a dist layer on such a small network, it seems to add a step that has to make me wait for a routing decision.

Am I wrong?

I don't know if this is going to win any friends ...

Again, it depends.  One of the biggest problems with any networks (no matter the size or complexity) is "generation change".  Whenever a generation change occurs (i.  e.  someone who knows more about the network and systems) people left behind tend to forget about some of the most basic information, such as old configurations and old IOS.

I can't say what configuration differences you and the slow network has/have but I would like to compare those first.  Only then will you be able to determine if QoS alone can make any improvements.  Frankly, I think the answer may not be as complex as QoS and could be as simple as incorrect configuration of the EtherChannel (for example).

I'm not saying that I disagree with you because you are not wrong.  If this is brain-storming then your idea should be on the table for everyone to consider.

leo,

you ARE winning friends with me, you answers are exactly the reason I posted these questions and replies. I want to get the perspective of someone else.

Brainstorming is exactly what I am looking for and I appreciate you throwing you ideas in.

I want to know why and at the moment, I was thinking the things I mentioned, which are also some of the differences:

QoS, routing slower than switching and trunk over etherchannel.

Ether channel was one question in my original post, what could make it slower than a trunk link?

On the incorrect etherchannel config, can you give me an example of what you are talking about?

On the incorrect etherchannel config, can you give me an example of what you are talking about?

There was one time when we didn't know why the server was slow.  No one cared and no one bothered.  Then one day I checked the logs and showed that the interfaces were going up/down.  The server wanted LACP but the etherchannel wasn't.  Don't know why it negotiated in the first place.  Wierd but that was the only time I saw something like that.

another thing is the server side is on NIC teaming but the switch side isn't on an etherchannel..my view on that is that it's suboptimal besides the fact the CAM table keeps on flushing since the switchports arent in a portchannel..also a good question is what kind of poor performance are they having?

So, you dont think the fact that one network is switching traffic and the other one is routing through each layer, (access to distribution, distribution to core) ahas any bearing on the latencey?

IT seems to me, that since everyting on one network is being switched by the 6509 core, either to another port on the switch, or to the WAN router, as opposed to on the other network, each layer having to make a layer three route decision would make a difference. Maybe not a big one, but the route processor on the layer three switche is supposed to be much slower than the hardware switching of layer 2.

So, you dont think the fact that one network is switching traffic and the other one is routing through each layer, (access to distribution, distribution to core) ahas any bearing on the latencey?

In my personal opinion, if a network is designed right (and regularly maintained) doesn't make a difference.

For example, a lot of people will post here on whether to use a Layer 2 or Layer 3 LAN.  Let's say that you funding is no issue, my next question is what knowledge base do you have.  Because it's not easy to do Layer 3 in your LAN if you don't have the knowledge base to maintain a Layer 3 LAN.

Maybe your network runs like a well-oiled machine is becasue you maintain your network, like a well-oiled machine, to be like a well-oiled machine. 

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When everything is working at best, on most modern L3 switches, there's very, very little speed lost doing L3 forwarding rather than L2 switching.  Again, that's at best, because L3 switches can encounter situations where L3 loses its hardware acceleration a little easier than L2 switches.

If your network requirements are such where a difference in latency of microseconds is important, then you'll most likely want L2.  E.g. difference in latency between store-and-forward vs. cut through switching.

From what you've described between the two networks, I would wonder whether they (network with L3 core) have been encountering unicast flooding.

The possible unicast flooding I have in mind is listed as case #1 in http://www.cisco.com/en/US/products/hw/switches/ps700/products_tech_note09186a00801d0808.shtml.

Look at Vmillers picture, how funny!

https://supportforums.cisco.com/people/vmiller