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

[Paolo Lucente]

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