Re: [L2tpext] [nvo3] New Version Notification for draft-fan-l2tp-vp-01.txt

> - To get hashing (for ECMP, RSS, etc.) in the network we'd almost
> certainly use L2TP over UDP, so L2TP-VP should probably have a format
> defined for use with UDP.
>
>
> There's also hashing for L2TPv3 directly over IP (e.g., RFC 5640)
>
Unfortunately to use that I'd need to replace all my hardware to
support it, and even if we did that the second we start putting L2TP
in IPsec we're right back to not having the hash. Same thinking
applies to GRE and it's use of key field for hash. I suppose it's not
by design, but UDP encap will likely be the de facto standard in the
data center-- it's not really that bad just a few bytes of overhead
buys us compatibility with a lot of devices. There's some pesky issues
to resolve, like whether UDP checksum is worthwhile and how to
interact with NAT, but if we do this right we should be a able to
provide a solution for all IP protocols (e.g.
http://tools.ietf.org/html/draft-herbert-gue-01 :-) )

Tom

> Thanks,
>
> Carlos.
>
> - Even with Type field, this still suffers from the same problem L2TP
> has that network devices won't be able to parse the packet beyond the
> L2TP header (the cookie field makes the header variable length). This
> eliminates the ability to implement the protocol with LRO for
> instance. I suggest you take four or five bits from reserved section
> for header length to resolve this (see example in GUE).
> - Cookie mechanism is an advantage over VXLAN and nvgre I believe, but
> why limit it to 32 bits? 64 bits is much stronger, and at some point
> we might even want 128 bits to do strong authentication.
>
> Some more general questions applicable to this and some other proposals.
>
> - "TNI field"-- this seems to use the same 24 bit left shifted format
> of nvgre and VXLAN. I still don't see the rationale for this! Why
> can't the full 32 bit field be allocated for vni? A large deployment
> will be using various levels of hierarchical allocation and possibly
> obfuscation of vni (TNI). The nvo3 requirements on this are vague
> ("100's of thousands of virtual networks"), but they clearly don't
> expect this the VNI to be a simple flat space either.
> - "Outer Ethernet Header"-- showing the outer Ethernet header in L3
> encapsulations examples is not necessary, use of Ethernet is not a
> requirement, and this is potentially very misleading. For instance,
> the outer Ethernet FCS does *not* protect the packet end to end in an
> L3 routed network. Personally, I think it would be more illustrative
> to show the IP packet in the inner Ethernet frame instead to see how
> its alignment is affected.
>
> Thanks,
> Tom
>
> B.R.
> Frank
>
> -----Original Message-----
> From: internet-drafts@ietf.org [mailto:internet-drafts@ietf.org]
> Sent: Thursday, April 10, 2014 11:22 AM
> To: Xialiang (Frank); Zhen Cao; Fanduoliang; Zehn Cao; Namgon Kim; Namgon
> Kim; Fanduoliang; Xialiang (Frank)
> Subject: New Version Notification for draft-fan-l2tp-vp-01.txt
>
>
> A new version of I-D, draft-fan-l2tp-vp-01.txt has been successfully
> submitted
> by Liang Xia and posted to the IETF repository.
>
> Name:         draft-fan-l2tp-vp
> Revision:     01
> Title:                L2TP-VP: Layer Two Tunneling Protocol - Virtualization
> Profile
> Document date:        2014-04-10
> Group:                Individual Submission
> Pages:                9
> URL:
> http://www.ietf.org/internet-drafts/draft-fan-l2tp-vp-01.txt
> Status:         https://datatracker.ietf.org/doc/draft-fan-l2tp-vp/
> Htmlized:       http://tools.ietf.org/html/draft-fan-l2tp-vp-01
> Diff:           http://www.ietf.org/rfcdiff?url2=draft-fan-l2tp-vp-01
>
> Abstract:
>   This document describes Layer Two Tunneling Protocol (L2TP)'s
>   virtualization profile (L2TP-VP), which reuses session header of L2TP
>   data message to securely support overlay networks for multiple
>   tenants, and simplifies tunnel setup by disabling all kinds of L2TP
>   control messages.
>
>
>
>
> Please note that it may take a couple of minutes from the time of submission
> until the htmlized version and diff are available at tools.ietf.org.
>
> The IETF Secretariat
>
>
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