[Sis-SCPS-INTEREST] Re: ZeroWindow segment

[miggy1 at free.fr]

Thank you for your help Eric,

I believe the problem is that I have only one Gateway. I would like to optimise
the communication between a client that doesn't have a SCPS-TP stack and my
Gateway :-p
Is ther a way to use SCPS with only one Gateway that could improve TCP
communications at the provider side (negociation of the supported skills and if
possible SCPS-TP)?

Thank you for the previous message wich explains well the establishment of a
connexion.

Miguel


Selon "travis at globalprotocols.com" <travis at globalprotocols.com>:

> Miguel,
>
> You may indeed have connectivity/configuration problems with the gateway,
> but I believe that your SCPS-TP gateways are interacting properly.
>
> I believe what you are seeing is the normal connection establishment
> behavior
> for the Reference Implementation of the SCPS-TP gateway.
>
> The end-to-end TCP flow is split into 3 pieces:
>
>
>    http client ----------> local GW ----------> remote GW -------> http
> server
>
> The local GW intercepts the SYN from the http client and immediately
> opens a connection between the http client and itself (spoofing the http
> server)
> and then performs an active open to the http server on its own behalf;
>
> In order to prevent the http client from sending any data until the local GW
> knows it has a connection to (who it thinks is) the http server, it
> advertises
> a zero window to the http client.
>
> When the local GW receives a SYN-ACK (and *maybe* a non-zero advertised
> window)
> in response to it's active open, it will send a window update to the
> http client.
>
> The same thing happens between the local and remote GWs.
>
> If there is indeed a problem for the local or remote GWs to connect to their
> "next hop" destination, you should receive a RST segment at the http client.
>
>
> So, you should be seeing this zero-window advertised on the SYN-ACK from the
> RI SCPS-TP gateway on all flows - even the successful ones.
>
>
> Hope this helps understand what you are seeing.
>
> Eric
>
>