[trill] Fwd: Mail regarding draft-ietf-trill-over-ip

[Donald Eastlake <[e-mail]>]

Forwarded with permission.

Thanks,
Donald
---------- Forwarded message ----------
From: Donald Eastlake <[e-mail]>
Date: Tue, Apr 28, 2015 at 9:26 AM
Subject: Re: Mail regarding draft-ietf-trill-over-ip
To: Mingui Zhang <[e-mail]>

Hi Mingui,

Thanks for these comments! See below.

On Tue, Apr 28, 2015 at 4:27 AM, Mingui Zhang <[e-mail]>
wrote:
> Hi,
>
> I read the document. It's comprehensive and well written. Below, several
comments for your information.
>
> 1.      It's not clear how the ports IPs are associated with the ports?
Maybe, we can add some words to explain that they can be got from DHCP or
manual configuration? Or we just say it is out the scope of this document.

Yes, they need to be configured. Could be DHCP or manual or maybe some
sort of orchestration thing... Seems reasonable to mention this in the
draft.

> 2.      Is it helpful to add a reference topology? Terminologies, such as
IP tunnel, port IPs, RBridges can be put onto this figure. A walk-through
example based on this reference topology can be used to explain how the IP
tunnel is set up, how does a TRILL Data packet get
encapsulated/decapsulated and transported in the IP tunnel. I think this
would be educational.

A few more network diagrams would probably be helpful. If you look at
the minutes from the Dallas TRILL WG meeting, the suggestion of having
a couple of example packets was supported...

> 3.      Both IP and TRILL have specified BFD. Since TRILL is dependent on
IP in TRILL-over-IP, it's unnecessary to have both TRILL and IP interact
with BFD. It's best to assert TRILL-over-IP will have the IP interact with
BFD. Please refer to https://tools.ietf.org/html/rfc5882#section-4.4

Well, if you are only going to use one then I agree with the section
you reference in RFC 5882 and you should do BFD over IP. But that
doesn't check the TRILL stack, just the IP and lower stacks. So we
could recommend just using IP BFD but I don't think we should try to
prohibit people from also using BFD over TRILL on the link.

> 4.      Is the IP link in this document "a single link (physical, or a
secure tunnel such as IPsec)"? Then, we can require the TTL "MUST be set to
the maximum on transmit, and checked to be equal to the maximum value on
reception (and the packet dropped if this is not the case)." See also RFC
5880 Section 9.

I don't think so. There is nothing wrong with the communication
between two TRILL IP ports being multiple IP hops. Even if IPsec is in
use, it could be integrated with the TRILL over IP port at one end but
at the other end, the IPsec implementation could be integrated with a
firewall a couple of hops from the RBridge...

> 5.      There are six tiny typos marked in the attached doc.

OK. We'll fix this up in the next version.

Maybe you should post these comments, or some of them, to the TRILL WG
mailing list. It would be good if there was more discussion of drafts
there. Or if it OK with you, I could just forward your comments and my
responses to the list...

Thanks,
Donald
=============================
 Donald E. Eastlake 3rd   [phone] (cell)
 155 Beaver Street, Milford, MA 01757 USA
 [e-mail]

> Thanks,
> Mingui