Hello Arashmid,
if a WiFi network needs to talk to 3GPP network for a roaming device, what
protocol are they going to use?
They could use Mobile IPv6, which was designed for exactly this purpose.
Do you think that would work?
Regards,
Charlie P.
On 3/27/2018 11:08 AM, Arashmid Akhavain wrote:
Tom,
Are you referring to a use case where the UE moves between different access
technologies?
Arashmid
IMO Unified concept in that encapsulation doesn’t seem to work i.n that
circumstance. When it comes to WiFi case, IETF has CAPWAP as the user plane
protocol which is also a foo-over-UDP variation.
Rigtht so if a WiFi network needs to talk to 3GPP network for a roaming device,
what protocol are they going to use?
-----Original Message-----
From: dmm [mailto:dmm-boun...@ietf.org] On Behalf Of Tom Herbert
Sent: 27 March 2018 10:03
To: Satoru Matsushima <satoru.matsush...@gmail.com>
Cc: dmm@ietf.org
Subject: Re: [DMM] IETF101 DMM WG Meeting Notes #1
On Mon, Mar 26, 2018 at 11:57 PM, Satoru Matsushima
<satoru.matsush...@gmail.com> wrote:
Thank you Tom,
Unfortunately I couldn’t find clear advantage of GUE against GTP-U.
(No offensive, please don’t get me wrong.)
I couldn’t see GUE in NVO WG doc list. But I can see much more foo-over-UDP
type encapsulation in IETF.
It's not in nvo3, it's now WGLC in intarea. See draft-ietf-intarea-gue and
draft-ietf-intarea-gue-extensions.
IMO Unified concept in that encapsulation doesn’t seem to work i.n that
circumstance. When it comes to WiFi case, IETF has CAPWAP as the user plane
protocol which is also a foo-over-UDP variation.
Rigtht so if a WiFi network needs to talk to 3GPP network for a roaming device,
what protocol are they going to use?
Nevertheless I think that that aspect would be a criteria for user plane
protocols comparison provided to 3GPP. But I don’t think it is good idea that
we provides 3GPP all kind of foo-over-UDP encapsulation protocols in IETF. It
would be better to pick SRv6 and some generic foo-over-UDP protocol to be
compared with GTP-U supported functionalities.
GUE is the generic foo-over-UDP protocol for that purpose.
Basic functionalities of GTP-U is that sequence number option,
extension-headers, and multicast and those should be the part of criteria. IMO
as you suggested, overhead size, performance, TE, extensibility and encryption
would be good idea for the criteria in addition to the above fundamental ones.
Best regards,
--satoru
2018/03/27 11:51、Tom Herbert <t...@quantonium.net>のメール:
On Mon, Mar 26, 2018 at 6:30 PM, Satoru Matsushima
<satoru.matsush...@gmail.com> wrote:
Thank you Tom for your suggestion.
Do you think that GUE has some advantages against GTP-U?
I believe so. GUE is designed to be a general purposed multi use case
encapsulation. The defined GUE extensions deal with problems and
provide features of encapsulation (header security, fragmentation,
payload security, checksum handling etc.). This is done without
resorting to expensive TLV processing. GUE also allows "private data"
that could be used for use case specific info-- so TLVs or GTP
extensions could be encoded so in that sense it's a superset of GTP
functionality. As I mentioned, GUE has a mode for encapsulating IP in
UDP with minimal overhead (direct IP over UDP).
When it comes to foo over UDP capsulation, does GUE benefit user plane beyond
GTP-U?
I think so. Perhaps the biggest advantage is the GUE can be used
accross different use cases and technologies. It's generic protocol
so it could be used for multiple use cases in a mobile network. For
instance, a UE might talk to a a low latency service application via
GUE. To the server this looks much more like simple virtualization or
encapsulation and GUE includes potential optimizations. Similarly,
GUE also could be use to connect across different access technologies
that might not be 3GPP (like roaming between WIFI and a mobile network).
Conceptually, other IETF defined encapsulations could also be used
for this (e.g. IPIP, LISP, GRE, VXLAN), but GUE is specifically
designed to be multi use case, low overhead, but still extensible.
We intend to use ILA in a similar multi-use case fashion, however
when encapsulation is required (like SR TE is needed, or we need an
encrypted tunnel) then I believe GUE is a good alternative for that
case to provide necessary functionality and extensibility.
Tom
2018/03/27 9:16、Tom Herbert <t...@quantonium.net>のメール:
On Wed, Mar 21, 2018 at 9:27 AM, Sri Gundavelli (sgundave)
<sgund...@cisco.com> wrote:
FYI. This is the notes that Carlos captured. Thank you Carlos!!
We are also waiting for Lyle to share his notes. Please review and
comment, if you see any mistakes.
With regards to SR encapsulation: "this is using IP-in-IP as default.
Why not using UDP encapsulation?"
There is some rationale for UDP encapsulation here to maximize
compatibility with the network and potentially intermediate nodes
like firewalls. For example, in the performance numbers that
Kalyani posted, the TPS for SR over IPIP routing was lower than
other encapsulations. The reason for this is that the particular
NIC (ixgbe) is not parsing over IPIP or using flow label to get a
good hash for RSS. This is symptomatic of network devices that
don't provide as good support for protocols outside of TCP and UDP.
There are likely routers that would not be able to provide flow
specific ECMP for similar reasons. There was a comment in dmm
meeting that ECMP for IPIP was expected to by solved by using flow
label in the hash. This is a great idea, but unfortunately there is
significant resistance to using flow label for this purpose since
it is not guaranteed to be persistent for a flow and that can cause
problems for stateful devices like firewalls.
UDP encapsulation is the typical answer to network protocol
compatibility. Several UDP encapsulation techniques have been
defined as well as some foo over UDP to run existing encapsulations
over UDP (e.g. MPLS/UDP, GRE/UDP). draft-ietf-rtgwg-dt-encap gives
a nice overview of considerations for UDP encap protocols.
If a UDP encapsulation is considered for use with SR, I would
suggest GUE is an option. GUE has some unique features:
- It's extensible (both common extensions are defined and allows
custom extensions per use case)
- It's generic (can encapsulate any IP protocol)
- It allows directly encapsulating IPv4 and IPv6 in UDP (to
minimize encapsulation overhead)
- It allows encapsulation of extension headers
The last point may be of particular interest to SR. SR over IPIP
might be more precarious compared to other encapsulations since it
introduces two "atypical" (i.e. not TCP or UDP) protocols. GUE
could be used to normalize SR packets to look like UDP to the
network. This might look something like:
IP|UDP|GUE|Routing_hdr|IP|payload
The UDP and GUE header are effectively treated as routing shim at
each segment hop so SR is processed as without regard to the encapsulation.
To intermediate nodes these packets looks like any other UDP packet
so there's no compatibility issue.
Tom
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