RE: [LinkSec] http://www.ieee802.org/linksec/Meetings/Jan03/Seaman_1_0103.pdf
Russ,
Thanks for the comments.
On the subject of replay you are right, generally I am not concerned about
replay being used to subvert a service for which most critical communication
is using an ordering/sequencing/duplicate suppression protocol on top.
However I would like to understand more about the threat that replay could
pose at this layer, my imagination is not doing a great job on this subject
so any examples (other than ones that simply result in denial of service)
would help.
I guess the big thing I didn't explain about the attractiveness of layer 2
service is the dramatic rise in interest in providing layer 2 services in
the service providers' world right now. In part this is because any
involvement in anything above layer 2 carries a higher support (and
especially training cost) for any provider who is not coming at this from
the point of view of an ISP (and many who are), in part it is because
organizations don't want their IP addressing plans interfered with simply
because they are replacing a T1 link with an Etherenet (like) higher speed
service, and in part as you say because there is quite a lot of non-IP
protocol around (you'd be staggered how much). The 'non-interference with
the customer' business goal of the service provider absolutely rules out
having the effects of securing the LAN/Etherent access link from customer to
provider propagate into the rest of the customers network (except to
management consoles, but that's a separate story).
Mick
> -----Original Message-----
> From: owner-stds-802-linksec@majordomo.ieee.org
> [mailto:owner-stds-802-linksec@majordomo.ieee.org]On Behalf Of Russ
> Housley
> Sent: Thursday, January 02, 2003 12:35 PM
> To: stds-802-linksec@ieee.org
> Subject: [LinkSec]
> http://www.ieee802.org/linksec/Meetings/Jan03/Seaman_1_0103.pdf
>
>
>
> I have a few comments on Mick's paper.
>
> Why link layer? on page 2. There is another reason. Not all
> networks run
> IP. Layer 2 offers a way to secure these other protocol
> suites without
> resorting to tunneling.
>
> Additional threats on page 4. In this section, you do not
> explain your
> reason for discarding a large collection of threats. Most of
> them are
> pretty obvious, but I do not think that the reason for
> omitting replay is
> obvious. In this scenario, the human user is a guest with a laptop
> connecting to the host's LAN. Is the reason that you omit
> replay that a
> LAN provides a connectionless service? If not, please explain.
>
> Russ
>
>