Re: [mpls-linux-general] delay Difference at Ingress and Egress

[nitin p. <tac...@ya...>]

Hi James,

--- "James R. Leu" <jl...@mi...> wrote:
> I would expect Ingress to be slower, I just didn't
> think it would
> be that slow :-)
> 
> Another thing to note is that when using tcpdump or
> the like, your
> forcing the MPLS stack to make a private copy
> (otherwise the version
> seen by tcpdump will be corrupt)
Won't that be the case will tethereal or any other
sniffer.And this will happen at all nodes including
LSR and ingress, so while doing comparison we can
neglect this:), please correct me.
Thanks,
Nitin

.  So you are
> forcing some aditional
> mem copies.
> 
> Armed with this new info I'll see if I can find some
> way to optimize
> the ingress LER case.
> 
> Thanks for your work.
> 
> On Sun, Dec 08, 2002 at 03:27:25PM -0800, nitin
> panjwani wrote:
> > Hi James,
> > 
> > Recently I measured the processing delay caused
> > protocol stack at Ingress, Egress and core.
> > 
> > Here are my results:
> > Ingress: 3.665 ms
> > Egress: 0.035 ms
> > Core: 0.018 ms
> > IP:0.023 ms
> > 
> > It makes sense that processing time at these nodes
> > will be in the following order
> > 
> > Ingress >= Egress > Core
> > 
> > What I am wondering, is huge delay at Ingress. If
> we
> > do L3 lookup + L2.5 forwarding even then it
> doesn't
> > clearify the reason of huge value. Can you please
> > explain in short how processing is taking place at
> > Ingress and how it can explain this delay.
> > 
> > Let me also explain my measuring technique, you
> can
> > corect me on this if I am doing something wrong.
> > 
> >       ---e1[Node]e0------
> > 
> > In this I am running tcpdump/tethereal at both e0
> and
> > e1. What I have understood is that libcap(used by
> > tcpdump/tethereal) captures the packet at device
> > driver, which is after it has been processed by
> > protocol stack for outgoing packet and before
> being
> > processed by protocol stack for incomming packet. 
> 
> > 
> > Thanks and Regards,
> > Nitin
> > 
> > 	
> > 					
> > 
> > 
> >     
> > 
> > 
> > 
> > 
> > __________________________________________________
> > Do you Yahoo!?
> > Yahoo! Mail Plus - Powerful. Affordable. Sign up
> now.
> > http://mailplus.yahoo.com
> > 
> > 
> >
>
-------------------------------------------------------
> > This sf.net email is sponsored by:ThinkGeek
> > Welcome to geek heaven.
> > http://thinkgeek.com/sf
> > _______________________________________________
> > mpls-linux-general mailing list
> > mpl...@li...
> >
>
https://lists.sourceforge.net/lists/listinfo/mpls-linux-general
> 
> -- 
> James R. Leu


__________________________________________________
Do you Yahoo!?
Yahoo! Mail Plus - Powerful. Affordable. Sign up now.
http://mailplus.yahoo.com