[c-nsp] 2950 Performance Problem

[Joe Goldberg]

Here are the 2 lines of the config that are relevant to the uplink port.  I
really hope you see something I am missing :-).

set port name       4/37 RowH
set trunk 4/37 on dot1q 1-1005,1025-4094

Thanks,
Joe



-----Original Message-----
From: Sam Stickland [mailto:sam_ml at spacething.org] 
Sent: Monday, July 26, 2004 8:33 AM
To: Joe Goldberg
Cc: 'Ryan O'Connell'; cisco-nsp at puck.nether.net
Subject: RE: [c-nsp] 2950 Performance Problem

What is the Cisco 6509 config on the other end of the trunk?

S

On Fri, 23 Jul 2004, Joe Goldberg wrote:

> 
> Thanks for you response.  I have checked for errors on both end of the
line
> and I am not seeing any.  The 6509 is set up as a simple dot1q trunk,
> nothing crazy or tricky.  I should mention though that the 6509 has an
MSFC2
> in it that is doing all the VLAN routing.
> 
> As for the pings, when the 2950 gets to its max load (at least in the
state
> it is now) of 12Mbps I start to drop pings of any size both to the switch
> and to servers that hang off the switch.  The servers on the switch drop
> pings outbound also.
> 
> Following your good idea, I tried putting two servers on the same vlan and
> got very good performance between the two on the same switch.  This would
> definitely point to an issue in the trunk, but I am still at a loss as to
> what that may be.
> 
> Here is just a snippet of code so you can see what I am doing on the 2950:
> 
> interface FastEthernet0/20
>  switchport access vlan 618
>  no ip address
> !
> interface FastEthernet0/21
>  switchport access vlan 617
>  no ip address
> !
> interface FastEthernet0/22
>  switchport access vlan 616
>  no ip address
> !
> interface FastEthernet0/23
>  switchport access vlan 615
>  no ip address
> !
> interface FastEthernet0/24
>  switchport mode trunk
>  no ip address
>  duplex full
>  speed 100
> 
> Thanks again for you assistance.  
> 
> Joe
> 
> -----Original Message-----
> From: Ryan O'Connell [mailto:ryan at complicity.co.uk] 
> Sent: Friday, July 23, 2004 3:18 PM
> To: Joe Goldberg
> Cc: cisco-nsp at puck.nether.net
> Subject: Re: [c-nsp] 2950 Performance Problem
> 
> Joe Goldberg wrote:
> 
> >I have a couple of 2950 switches in my data center that we are
evaluating.
> >I am getting terrible performance on them.
> >  
> >
> 
> Things that spring to mind include:
> - Check for errors both ends of all links. (I.e. on the 6509 and the 
> servers as well as the 2950) I guess you already have done this, but I 
> thought I'd mention just in case. :-)
> - Try continuous pings, look for dropped packets vs. high RTT. In 
> particular, try very large pings. (2k per ping should do)
> - Try putting two ports in the same VLAN, and measure performance across 
> those two ports. This will narrow down the fault to the 2950/6509 link 
> and the 2950 itself.
> 
>