Scenario:
Point to point OC3 ATM circuit between two sites that are thousands of miles apart. 3845 on one side with a PA-A3-OC3SMI and a 7206 on the other side with a NM-1A-OC3-POM.
Problem:
Using iPerf, with a window size of 4MB, I can sustain 120Mbps of TCP traffic in one direction, but the other direction will not sustain a steady rate... it goes up to 70Mbps then down to 2Mbps, then back up to 80Mbps, then down to 5Mbps, etc... UDP traffic in both directions works perfect, at near OC3 rates.
Point to point transfers using HTTP, FTP, SMB, etc... from one side to the other will never go above 15Mbps.
Question:
I don't know a lot about ATM, so I am confused as to why I am having issues pushing data over this link. What am I missing?
No errors on any of the ATM interfaces, or the layer 2 path on the LAN side of the routers. I am about as close as I can get to the router on the LAN side without plugging directly into it.
Configs:
7200:
interface ATM2/0
no ip address
no ip redirects
no ip unreachables
no ip proxy-arp
ip flow ingress
no atm ilmi-keepalive
!
interface ATM2/0.1 point-to-point
bandwidth 2048
ip address 192.168.158.153 255.255.255.252
no ip redirects
no ip unreachables
no ip proxy-arp
ip flow ingress
ip ospf network point-to-point
snmp trap link-status
pvc 0/33
vbr-nrt 149760 149760
3800:
interface ATM2/0
no ip address
no ip redirects
no ip unreachables
no ip proxy-arp
no atm ilmi-keepalive
!
interface ATM2/0.1 point-to-point
bandwidth 2048
ip address 192.168.158.154 255.255.255.252
no ip redirects
no ip unreachables
no ip proxy-arp
ip flow ingress
ip flow egress
ip ospf network point-to-point
ip ospf priority 2
ip ospf mtu-ignore
no snmp trap link-status
pvc 0/33
vbr-nrt 149760 149760
