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TTCP speed in different directions

I am troubleshooting some speed issues that I might be having and using TTCP and iperf/jperf. I am testing the LAN speed between our local router and local desktop.

When I run TTCP transmit on the Cisco and receive on the local desktop I get speeds right around 90Mbps, which I would expect because the switch between the Cisco router and the desktop is only 10/100.

When I run TTCP receive on the Cisco and transmit from the same desktop I only get speeds of about 24Mbps to the router.

The router is a 2911 wiht gigabit ports. The switch between the 2 devices is only a 10/100 switch, so I expect to only get around 90Mbps but 24 seems very low.

Reza Sharifi
Hall of Fame Expert

Even though, the 2900 has multiple 10/100/1000 onboard ports, it doesn't mean you will get 100Mbps or anything close to that per port.  The 2911 fast/CEF switches 180.73Mbps for the entire box.

see below doc for more info:


is there anyway to show what the current traffic is? show the pps or Mbps for the box? i dont think that we are anyhwere near the 180Mbps. We only have 2 interfaces enabled on the router and one is a WAN link with a 50Mbps pipe.

I also have no ACL's enforced on any interfaces at the moment, no traffic encryption or complression.

I know this is a rather old thread...

On a 2911 router with gigabitEthernet 0/0 LAN and gigabitEthernet 0/1 WAN (300Mbps internet connection), NAT enabled when we have disabled cef (no ip cef) the maximal IP traffic speed was arround 60 Mbps. When we have enabled cef:

ip cef

(no ipv6 cef )

the IP traffic speed was arroung 250Mbps-310Mbps on both upload and download

Joseph W. Doherty
Hall of Fame Expert


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If you're using the router itself as either a source or sink, performance might be much less than what the router can do forwarding traffic.  Doubtful Cisco put a lot of effort in optimizing a router's TTCP performance.