ack need some help with cisco stuff

[ppaik]

The Network Engineer left our company and we have yet to find a replacement. I do know a little about Networking, so I have been playing around trying to get a feel for it, but this problem is not solveable to me. I have looked online to find nothing......I 've been trying to figure this out for the past 2 days and I haven't gone anywhere with it.

I recently set up 2 servers on Win2k3 with Network Load Balancing for FTP servers at work. We used to have two servers with different IP addresses that people had to choose from. Ever since the Network Load Balancing setup, we are only using 100meg instead of 200...people are saying dl is slow...I have no idea what the problem is.

Is it something on the system side? Or is it a Networking issue? We have a 300 meg line going into the 2950 Cisco Switch where the FTP servers are. The 300 meg line is setup with 3 wires and are configured on a port channel...

Here is the setup on the following:

2950 Switch (Switch to NLB Servers)

interface FastEthernet0/22
no ip address
channel-group 1 mode desirable
!
interface FastEthernet0/23
no ip address
channel-group 1 mode desirable
!
interface FastEthernet0/24
no ip address
channel-group 1 mode desirable


6500 Router

3/35 connected desirable silent 337 1747
3/36 connected desirable silent 337 1747
3/37 connected desirable silent 337 1747

 

[spidey07]

IIRC you need to do some special stuff switch wise for MS network load balancing.

Is this OS load balancing or are you teaming the NICs in a single box?

From your configs it looks like you are trying to form an etherchannel on three ports between the two switches. If that is the case we'll need to look at the IP/subnetting scheme and pick a load balancing algorithm. As with most load balancing with etherchannel only one link is used for a particular conversation.

This has a few good MS links to understand how windows load balancing works network wise.
http://www.cisco.com/en/US/tech/tk389/t...logies_tech_note09186a008011b481.shtml

 

[ppaik]

I setup NLB from Win2k3. I don't know how to do it on the Networking side, so I did OS based NLB.

As far as the channeling goes, when we had two servers with 2 ips that people were downloading from, it was doing about 200megs. After I installed the NLB, 100megs max. I was just wondering if it was a Network issue. The previous engineer told me that channeling 3 ports would give us 300 megs into the switch...but Im wondering why we are only utilizing 100 right now...

 

[spidey07]

well channeling is done with a single host.

host w/3 nics <--->3 ports on single switch (that is configured for channeling)

Could you please desribe each server and exaclty how they are connected to the switch? I'm a little confused because in your first post you have two switches, each with 3 ports channeled.

 

[ppaik]

Internet Feed to 6500
6500 has 3 lines going to the 2950 (engineer said this would allow 300 megs)
2 nlb servers. Each server is connected to the 2950 as well.

 

[ppaik]

I'm thinking it has something to do with the 2950...when we had two different servers connected to the 2950, we were getting 200 max. Now with one virtual ip to the 2950, we're getting 100 max. In both cases, we should have gotten 300 max or close to it no?

 

[spidey07]

Well this has to do with how etherchannel works then.

Each conversation - for instance an ftp client talking to an ftp server will only use a single link in the etherchannel. Its really load sharing and not load balancing.

Depending on the switch you can load share based on mac addresses or IP addresses. You could try changing this to better suite your application.

Sometimes folks assume "gee, I channeled 8 ports together and should be getting 800 Mbs", it doesn't quite work that way.

really good document on etherchannel...
http://www.cisco.com/en/US/tech/tk389/t...logies_tech_note09186a0080094714.shtml

 

[ppaik]

hmm, will this work then? The two ports I have connected to the servers on the 2950...if i channel those two ports...will that work?

btw, thanks for all your help spidey...i really appreciate it.

 

[spidey07]

I don't know. I'm not familiar with MS load balancing. If you post a good technote/article from MS that provides good information (like exactly what is happening at layer2 and 3) I may be able to help.

Etherchannel really is only used between two devices - not 3.

 

[ppaik]

ok that makes sense...I'll try to read up a bit more. If I find any answers I'll update. But thanks for the help...you got my brain working a bit now

 

[ppaik]

EDIT/Update: I got it working past 100megs by connecting directly to the 6500

I tried configuring the 2950 to do load balancing from src and dest...but I was getting the same results. I don't know why, but I'm assuming the the channeling was the issue on the 2950...no clue but I'm relieved it works...Thanks for the help spidey, it helped me alot.

 

[spidey07]

well if the 2950 was balancing one way and the 6500 another I could see unusual results happening.