Subject: [Tsvwg] "Intelligent" LAN adapters

From: Ramesh Shankar <[email-masked]>
Date: Fri, 19 Oct 2001 07:01:47 -0600

Thought I would find out any pointers/experience with "Intelligent" LAN 
apdaters which are supposed to have a whole TCP/IP stack on them.

A related question: if I have two such adapters, how do I decide which 
one to use for outbound interface given that the IP layer is on the stack?

Thanks,

S.R.

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From: "Somesh Gupta" <[email-masked]>
Date: Fri, 19 Oct 2001 11:38:14 -0700

On your second question, this an area of differentiation among
vendors. Ideally the TCP Offload Adapter + driver + host stack
combination should not require the application to make this
choice - but instead should make the decision on behalf of
the application.

The primary mechanism for deciding this is the routing table.
This works quite well if all the adapters plugged into a
system have the same capability. It does require the APIs
provided by the adapters to accomodate high availability
features such as migrating IP addresses (from adapter to
adapter). It also requires host stack changes to do
route lookup at a higher point in the stack.

However a completely unmodified routing mechasism will not
work in an environment that mixes "intelligent" (varying degree)
and "non-intelligent" adapters. So when picking a adapter
in a system with multiple adapters of different capabilities,
the adapter capability may have to be a parameter into the
routing table (this is applicable when going through a gateway).
If there are only default gateways, this should be fairly
straightforward to accomodate.

Somesh

> -----Original Message-----
> From: [email-masked] [mailto:[email-masked]]On Behalf Of
> Ramesh Shankar
> Sent: Friday, October 19, 2001 6:02 AM
> To: tsvwg
> Subject: [Tsvwg] "Intelligent" LAN adapters
>
>

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From: "Sriram Rupanagunta" <[email-masked]>
Date: Fri, 19 Oct 2001 16:02:05 -0500

> The primary mechanism for deciding this is the routing table.

I think your answer to the original question is that this is decided
by another IP stack on host (which maintains this routing info), 
which is different from the IP stack on each adapter. This IP stack
(or a host driver) does not terminate TCP connections, but assists 
the routing of application data to the "right" off-load adapter.