[c-nsp] 2811 performance on an Ethernet over SONET connection??

[Paolo Lucente]

Hi Joe,

As you speak about window scaling, i understand your tests are revolved around
TCP; then, neither of CAR and policying will help; you need to shape outbound.

A simple test is:

policy-map SHAPE-14M
 class class-default 
  shape average 1400000
!
interface FastEthernet0/0
 ...
 service-policy output SHAPE-14M
!

Cheers,
Paolo


On Fri, Feb 15, 2008 at 11:28:38PM -0600, Joe Freeman wrote:
> I tried both straight rate-limiting and traffic policing with no change in
> symptoms.
> 
> On 2/15/08, Paolo Lucente <pl+list at pmacct.net> wrote:
> >
> > Hi Joe,
> >
> > it might be you need to apply some outbound shaping onto the interface
> > facing
> > the Internet due to the difference between the access rate (100Mbps) and
> > the
> > CIR (15Mbps). This could explain why degraded throughput is experienced
> > only
> > upstream. I can't really imagine it could be a CPU-related issue, but all
> > in
> > all it's worth checking it.
> >
> > Cheers,
> >
> > Paolo
> >
> >
> >
> > On Fri, Feb 15, 2008 at 02:59:55PM -0600, Joe Freeman wrote:
> > > Folks-
> > >
> > > I have a situation in which a customer has a 2811 router connected to an
> > > Ethernet over SONET pipe from me onto which he subscribes 15M of
> > Internet.
> > > The SONET portion of the pipe currently has 11 VT1.5's cross-connected.
> > This
> > > customer is seeing asymmetric performance on the link in that his upload
> > > speeds are significantly lower than the download speeds.
> > >
> > > Given that there is no congestion on the network, plenty of bandwidth is
> > > available, and no significant packet/frame loss errors are seen at any
> > > point, including on the SONET ADM boxes, I'm sort of at a loss. Further,
> > I
> > > can plug my laptop into this port with 1323 opts, nagle, window scaling,
> > and
> > > a large MAX window size and test absolutely fine across the circuit. I
> > plug
> > > the same laptop into the lan side of his router (Fa0/1, below) and I see
> > the
> > > significant drop of which he's complaining.
> > >
> > > I've also verified the speed/duplex settings are appropriate and are
> > working
> > > correctly. One other thing I've noticed is that as I increase bandwidth
> > > across the SONET ring, the disconnect between upload and download speeds
> > > appears to grow on an almost log scale.
> > >
> > > Anyone have any thoughts or tips on this?
> > >
> > > Thanks-
> > > Joe
> > >
> > > R1#sho ver
> > > Cisco IOS Software, 2800 Software (C2800NM-IPBASE-M), Version 12.4(3d),
> > > RELEASE SOFTWARE (fc3)
> > > Technical Support: http://www.cisco.com/techsupport
> > > Copyright (c) 1986-2006 by Cisco Systems, Inc.
> > > Compiled Wed 19-Apr-06 09:18 by alnguyen
> > >
> > > ROM: System Bootstrap, Version 12.4(1r) [hqluong 1r], RELEASE SOFTWARE
> > (fc1)
> > >
> > > nettech uptime is 1 hour, 23 minutes
> > > System returned to ROM by power-on
> > > System image file is "flash:c2800nm-ipbase-mz.124-3d.bin"
> > >
> > > Cisco 2811 (revision 53.51) with 251904K/10240K bytes of memory.
> > > Processor board ID FTX1027A1HS
> > > 6 FastEthernet interfaces
> > > DRAM configuration is 64 bits wide with parity enabled.
> > > 239K bytes of non-volatile configuration memory.
> > > 62720K bytes of ATA CompactFlash (Read/Write)
> > >
> > > Configuration register is 0x2102
> > >
> > > R1#sho run
> > > Building configuration...
> > >
> > > Current configuration : 1115 bytes
> > > !
> > > version 12.4
> > > service timestamps debug datetime msec
> > > service timestamps log datetime msec
> > > no service password-encryption
> > > !
> > > hostname R1
> > > !
> > > boot-start-marker
> > > boot-end-marker
> > > !
> > > !
> > > no aaa new-model
> > > !
> > > resource policy
> > > !
> > > ip subnet-zero
> > > !
> > > !
> > > ip cef
> > > !
> > > !
> > > no ip domain lookup
> > > ip domain name R1.net
> > > !
> > > !
> > > !
> > > !
> > > interface FastEthernet0/0
> > >  description to Internet
> > >  ip address 66.211.51.10 255.255.255.252
> > >  ip nat outside
> > >  load-interval 30
> > >  duplex auto
> > >  speed auto
> > > !
> > > interface FastEthernet0/1
> > >  description To LAN
> > >  ip address 192.168.1.1 255.255.255.0
> > >  ip nat inside
> > >  duplex auto
> > >  speed auto
> > > !
> > > interface FastEthernet0/0/0
> > > !
> > > interface FastEthernet0/0/1
> > > !
> > > interface FastEthernet0/0/2
> > > !
> > > interface FastEthernet0/0/3
> > > !
> > > interface Vlan1
> > >  no ip address
> > > !
> > > ip classless
> > > ip route 0.0.0.0 0.0.0.0 66.211.51.9
> > > !
> > > no ip http server
> > > ip nat inside source static 192.168.1.2 interface FastEthernet0/0
> > > !
> > > !
> > > control-plane
> > > !
> > > banner motd ^C Authorized personel only, please. ^C
> > > !
> > > line con 0
> > > line aux 0
> > > line vty 0 4
> > >  password cisco
> > >  login
> > > !
> > > scheduler allocate 20000 1000
> > > !
> > > end
> >
> >