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

[Joe Freeman]

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