Re: Echo request and echo reply

>It is Google specific. They do a lot of "optimizations" to save on
>bandwidth.

I think they also do some low level network optimization as well. I've seen
networks having MTU issues actually be able to get to www.google.com when
they could not get to any other site. I didn't get a chance to break out
the shark to verify the exact size because the customer "intrawebs" was
down. I might break some MTU later this afternoon in the lab and see what
they are doing now that you guys mentioned google
specific. Curiosity always kills this cat :>

max

On Tue, Nov 1, 2011 at 12:27 PM, Brian Dennis <bdennis_at_ine.com> wrote:

> It is Google specific. They do a lot of "optimizations" to save on
> bandwidth. Just run an HTML validator against their site:
>
> http://validator.w3.org/check?verbose=1&uri=http://www.google.com/
>
> Additionally if you look at the HTML source of www.google.com you'll
> notice that they don't include </body> or </html>. The amount of
> bandwidth saved is really amazing for small things like this when you're
> working on the scale of Google's networks.
>
>
> Brian Dennis, CCIEx5 #2210 (R&S/ISP-Dial/Security/SP/Voice)
> bdennis_at_ine.com
>
> Internetwork Expert, Inc.
> http://www.INE.com
>
>
>
> On 11/1/11 7:20 AM, "Piotr Matusiak" <pitt2k_at_gmail.com> wrote:
>
> >It seems to be Google specific in this case as when I ping cisco.com it
> >replies with the same size :)
> >
> >Regards,
> >--
> >Piotr Matusiak
> >CCIE #19860 (R&S, Security), CCSI #33705
> >Technical Instructor
> >website: www.MicronicsTraining.com <http://www.micronicstraining.com/>
> >blog: www.ccie1.com
> >
> > If you can't explain it simply, you don't understand it well enough -
> >Albert Einstein
> >
> >
> >2011/11/1 Carlos G Mendioroz <tron_at_huapi.ba.ar>
> >
> >> Hmm,
> >> The question was specific to 8.8.8.8, which is a specific host (or set
> >>of
> >> hosts :) that actually DO NOT behave like RFC-792 asks.
> >>
> >> FTR, RFC-792 says:
> >>
> >> Data received in an ICMP Echo Request MUST be entirely included in the
> >> resulting Echo Reply. However, if sending the Echo Reply requires
> >> intentional fragmentation that is not implemented, the datagram MUST
> >> be truncated to maximum transmission size (see Section 3.3.3) and
> >> sent.
> >> ...
> >>
> >> If a Record Route and/or Time Stamp option is received in an ICMP Echo
> >> Request, this option (these options) SHOULD be updated to include the
> >> current host and included in the IP header of the Echo Reply message,
> >> without "truncation". Thus, the recorded route will be for the entire
> >> round trip.
> >>
> >> but testing shows that 8.8.8.8 answers with small reply when data size
> >> gets over 64 bytes.
> >>
> >> -Carlos
> >>
> >> Piotr Matusiak @ 01/11/2011 10:00 -0300 dixit:
> >>
> >>> Yes
> >>>
> >>> Regards,
> >>> --
> >>> Piotr Matusiak
> >>> CCIE #19860 (R&S, Security), CCSI #33705
> >>> Technical Instructor
> >>> website: www.MicronicsTraining.com <http://www.micronicstraining.com/>
> >>><
> >>> http://www.micronicstraining.**com/
> >>><http://www.micronicstraining.com/>>
> >>>
> >>> blog: www.ccie1.com
> >>>
> >>> If you can't explain it simply, you don't understand it well enough -
> >>> Albert Einstein
> >>>
> >>>
> >>> 2011/11/1 amin <amin_at_axizo.com>
> >>>
> >>> Hi experts,
> >>>>
> >>>>
> >>>>
> >>>> If I do extended ping 8.8.8.8 size 2000, this is the size of the echo
> >>>> request, what will be the size of the echo replay? It will be the same
> >>>> size??
> >>>>
> >>>>
> >>>>
> >>>> Regards,
> >>>>
> >>>> Amin
> >>>>
> >>>>
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> >>>
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>
> >> --
> >> Carlos G Mendioroz <tron_at_huapi.ba.ar> LW7 EQI Argentina
> >
> >
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Received on Tue Nov 01 2011 - 13:15:26 ART