Okay so I just setup the following in my lab:
- SSG 5 256MB ScreenOS 6.3
- SRX 100B 512MB JunOS 12.1X46 (the SRX210HE2 has a faster CPU and more memory so should be even quicker).
- Another BGP Router
I connected the SSG and SRX directly via 100mbit and then setup a route based 3DES/SHA1 ipsec VPN between the two.
I then connected both the SSG and the SRX (using a different port on both SSG and SRX) to another router and setup some BGP sessions. Both SSG and SRX received about 300 routes via BGP.
I then ran a secure copy (scp) between my MacBook Air on the SSG5 to a low end asus atom box on the SRX100 side. I copied a couple of different iso files (so large files), about 5GB in total.
I was able to just hit 7megabytes/sec between the two machines via the IPsec VPN.
While testing I watched my external BGP router and both SSG and SRX kept the BGP session going without issues.
I also checked the CPU load on both devices.
The SSG 5 was running at 87% CPU (get perf cpu)
, the command line interface was slow and the status light no longer flashed evenly. The device was only just keeping up.
The SRX 100 was running at 73% CPU (show chassis forwarding) (Real-time threads CPU utilization). So almost 15% less, the command line interface was also responsive and worked correctly.
Therefore I believe there is probably a configuration issue or other bug you are hitting, you should easily be able to push 20mbit/sec of image files through the SRX.
Can you please post your SRX configuration for us to look at? Also check to ensure that you are getting full duplex on your ethernet connection.
Thanks!