On Sun, 2 Jun 2019 at 18:35, Jared Mauch <[email protected]> wrote: > > > > > On Jun 2, 2019, at 3:50 AM, James Bensley <[email protected]> > > wrote: > > > > > > I recently upgraded from eXR 6.5.2 to 6.5.3 and pushed the files using > > SCP to the router from a jump box, which was on the same LAN as the > > management interface on the RSP. It was copying at 100Mbps (the speed > > of the OOB switch) so I think in eXR these issues are more or less > > fixed. > > I don’t believe you have enough data to conclude that. When copying data > from longer distances away (eg: global network with centralized file > server/images) I previously saw bad behavior, but when the latency was low it > worked well.
Right, that's why I made a vague statement. > This is what led me down the path to determine what was going on with the XR > TCP stack. I suggest capturing a PCAP and figuring out if it’s doing SACK or > window scaling with appropriate sized buffers. > > Even from bash/run on eXR you may also want to check this out. This led to > an effort to internally anycast resources as it was a problem that was easier > solved that way as Cisco was afraid to fix the TCP stack, and got even more > worried when we saw issues with their SACK implementation and reported the > details. (It was doing an ACK of the wrong number of bytes, which caused > drama with super strict stateful firewalls that tried to be too smart for > their own good). > > Also beware TCP disconnects as they don’t do TCP keepalives by default so any > session that drops in the middle of a transfer would cause it to act like a > file transfer is ongoing even though TCP was dead). All good info. I was just adding an anecdote that I have personally experienced very slow TCP transfer times on cXR and much faster times on eXR (my slow experiances on cXR were also when copying from a jump box on on the OOB LAN). I am semi interested to dig deeper but for me it's plenty "fast enough" now so it doesn't warrant any more time. Cheers, James. _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
