[j-nsp] FTP limitations between back to back Junipers

[Jesper Skriver]

On Wed, Jan 22, 2003 at 04:40:55PM -0000, Nic McCartney wrote:

> Guys,
>
> Anybody know of any limitations to FTP between 2 Juniper routers back
> to back connected via a DS-3? Should user be able to ftp at line speed
> if there is no other traffic on the link?

If you ftp to/from the RE you will be limited by the 100 Mbps ethernet
between the RE and the PFE, in addition to this, you have to consider
the following.

- Control traffic has preference on the RE <-> PFE link
- "Normal" TCP behaviour, the TCP window on a Juniper router is 16 kB,
  so if your DS3 has a RTD of 50 ms, you will have a maximum throughput
  of

    16 kB
  --------- = 320 kB/s = 2.56 Mbps
    50 ms 

/Jesper