Subject: RE: iSCSI over TLS

From: "Julian Satran" <[email-masked]>
Date: Fri, 9 Nov 2001 16:14:54 +0200

Bill,

The one "tiny" item you forgot to mention is that TLS records span TCP and 
iSCSI PDU boundaries. TLS records can't be decrypted in face of TCP packet 
loss and markers/alignment can't be recovered (to be more precise require 
a lot more tweaking of the stacks).

Julo

"Bill Strahm" <[email-masked]>
08-11-01 23:55
Please respond to "Bill Strahm"

        To:     Julian Satran/Haifa/IBM@IBMIL
        cc: 
        Subject:        RE: iSCSI over TLS

Julian,

I do not understand how TLS interferes with delivery of iSCSI packets any
more than IPsec.  In either case your TOE MUST decrypt the packet and deal
with the results.  I do not see how this changes the problem if the packet
is decrypted before going to the TOE (again the hardware to do this MUST 
be
on the NIC device) or after going through the TOE processing...
Quick summary of what I think needs to happen
IPsec
1) receive L2 packet
2) determine it is IP
3) Apply packet policy based on L3 header
4) Decrypt packet - verify it is covered by the SA
5) Pass to L4 (TCP) for processing
6) Verify Framing/etc.
7) Done
TLS
1) Recieve L2 Packet
2) Pass to L3
3) Pass to L4 (TCP) for processing
4) Decrypt packet
5) Verify Framing/etc
6) Done

It turns out the policies for TLS are much simpler than for IPsec, the
application itself gets to determine if security should be turned on or 
not
(rather than another application pushing policies into an SPD) and I don't
see a difference in the security offload requirements.  In many cases TLS
will go through firewalls/NAT/NATP much better than IPsec, allowing for a
wider deployment model.

Bill Strahm
+========+=========+=========+=========+=========+=========+=========+
Bill Strahm     Software Development is a race between Programmers
Member of the   trying to build bigger and better idiot proof software
Technical Staff and the Universe trying to produce bigger and better
[email-masked] idiots.
(503) 601-0263  So far the Universe is winning --- Rich Cook

-----Original Message-----
From: [email-masked] [mailto:[email-masked]]On Behalf Of
Julian Satran
Sent: Tuesday, November 06, 2001 10:17 PM
To: [email-masked]
Subject: Re: iSCSI over TLS

Peter,

A group of us seriously considered TLS. The main reason for dropping it
was that it would interfere with any mechanism we could think of doing
framing and steering and we thought that framing and steering are
essential at 10Gbps and over.

Julo

"Peter Mellquist" <[email-masked]>
Sent by: [email-masked]
07-11-01 02:15
Please respond to "Peter Mellquist"

        To:     <[email-masked]>
        cc:
        Subject:        iSCSI over TLS

I am aware that the ips group is leaning toward IPSEC as for the security
solution but I am interested if anyone is also considering using Transport
Layer Security (TLS)?

I am concerned that the requirement for IPSEC might make TOEs  more
complex
than they need to be. Can TLS be optionally used as well as defined by the
specification? This could allow TOE vendors to only be concerned with
providing normal IPv4 / ipv6 and leave the security to a higher layer. A
TLS
stack sitting above the TOE could then handle security very well. Also, I
anticipate that the first generation of TOEs will not support IPSEC. With
a
iSCSI/TLS we could enable security solutions with the first generation of
TOEs and get speed and security.

Are any TOE vendors planning to support IPSEC?

Can TLS or IPSEC be supported?

-peter

Peter Mellquist
Seven Systems Technologies
575 Menlo Drive Suite 2
Rocklin CA
916-577-1275
[email-masked]

---

From: "Sukanta Ganguly" <[email-masked]>
Date: Fri, 09 Nov 2001 07:42:52 -0800

Julian,
   It is correct that TLS records span TCP packets, but how does that become anymore of a problem. For packets to be resend via the TCP mechanisms, the sender TLS layers prepares the TLS record and then hands it over to TCP, TCP may break that TLS layer into e.g. say 5 packets and sends them to the receiver. If the receiver does not retrieve packet number 3, it will be resend by the sender.
  I did not see the problem that TLS brings into the picture. Also, what tweaking of the stack are you referring to in this scenario. This is just general handlinf of packets that are  done anyway. iSCSI will only make sense of the packet after TLS decrypts the packets. Did I miss something here ???

SG

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