Internet DRAFT - draft-xie-v6ops-ipv6-development-chinatelecom
draft-xie-v6ops-ipv6-development-chinatelecom
V6OPS Working Group C. Xie
Internet-Draft C. Li
Intended status: Informational C. Ma
Expires: January 8, 2021 Q. Yuan
China Telecom
July 7, 2020
IPv6 development and current status of China Telecom
draft-xie-v6ops-ipv6-development-chinatelecom-00
Abstract
The draft presents China Telecom's deployment of IPv6 in multiple
scenarios for the whole network transition, including the history,
transition strategy, measurements and challenges.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on January 8, 2021.
Copyright Notice
Copyright (c) 2020 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Xie, et al. Expires January 8, 2021 [Page 1]
Internet-DraIPv6 development and current status of China Tele July 2020
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Requirements Language . . . . . . . . . . . . . . . . . . . . 2
3. Retrospection . . . . . . . . . . . . . . . . . . . . . . . . 2
4. IPv6 deployment in multiple scenarios . . . . . . . . . . . . 3
5. IPv6 measurement . . . . . . . . . . . . . . . . . . . . . . 5
6. Challenges . . . . . . . . . . . . . . . . . . . . . . . . . 6
7. Security Considerations . . . . . . . . . . . . . . . . . . . 7
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7
9. Normative References . . . . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction
As one of the 3 operators in China, China Telecom not only provides
voice, household broadband and mobile services to public customers,
but also provides leased-line, VPN, IDC and cloud computing services
to enterprise customers. Up to now, the quantities of mobile users
and household users have reached to 308 million and 123 million
respectively, of which 267 million are LTE/4G users. With the
evolution of mobile networks, China Telecom has begun to provide SA-
based 5G services. In addition, China Telecom also provides oversea
services in some regions, for instances, North America, Europe and
Australia, etc.
To support the services provisioning for tremendous amount of users
in different scenarios, a large-scale IP infrastructure has been
setup and operated. This document presents IPv6 deployment in the
large-scale IP infrastructure of China Telecom, including its
history, deployment strategy, measurements and challenges.
2. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
3. Retrospection
China Telecom's IPv6 work can trace back to 2001, considering that
IPv6 is the future of IP network and IPv4 address will be exhausted
sooner or later, China Telecom begun to test IPv6 over ADSL network,
and successfully tunneled through the workflow of IPv4/IPv6 dual-
stack service in broadband network then.
Xie, et al. Expires January 8, 2021 [Page 2]
Internet-DraIPv6 development and current status of China Tele July 2020
In 2012, IPv6 deployment field-trial for MANs (i.e., Metro Area
Network) was implemented in Jiangsu and Hunan Provinces, Dual-
stack([RFC4787]), DS-Lite([RFC6333]) and Lightweight
4over6([RFC7596]) and IVI([RFC6144]) were tested in the trial. After
the field trial IPv6 capability expanded and covered more than 10
million users.
Particularly, since Chinese government launched the IPv6 action plan
in 2017 November, IPv6 commercial deployment was accelerated and
extended to nearly every part of the network infrastructure,
including enable IPv6 in the cloud computing platform, which is
essential for customer to enable IPv6 in their application system.
After more than two years efforts, comprehensive IPv6 deployment in
the IP infrastructure have been achieved.
4. IPv6 deployment in multiple scenarios
China Telecom's IP infrastructure is an multi-AS system,as
shown in figure 1,it consists of backbone networks, MANs, IP RAN,
EPC(i.e., mobile core network of LTE), IDCs, cloud resource pools,
etc.
Xie, et al. Expires January 8, 2021 [Page 3]
Internet-DraIPv6 development and current status of China Tele July 2020
.------. .-----. .-----.
/ \ / \ / \
/ Other \ / Foreign \ / Foreign \
( Domestic ) ( Operators ) ( Operators )
\Operators / \ / \ /
\ / \ / \ /
`----- '\ /`-----' `--+--'
\ / |
\ / |
\ / |
\.-----./ .--+--.
/ \ / \
/ \ / \
( ChinaNet )--------------------- ( CN2 )
\ / \ /
\ / \ /
`------'\ /--+--'
| \ / |
| \ / |
| \ / |
_______|______ \ _________________ / ____|_________
| | | | | |
| MANs/ | | IDCs/Cloud | | 4G/5G Mobile |
| IPRANs | | | | Core Networks|
+--------------+ +-----------------+ +--------------+
Figure 1: Overall architecture of network infrastructure
There are two inter-connected backbone networks, ChinaNet and CN2,
both have not only nation-wide coverage, but also have some oversea
POPs. The two backbones provide high-speed data switching
domestically and overseas. MANs, EPCs, IDC and cloud resource pools
are connected to the two backbones. ChinaNet is native-IP network,
which provides high-speed data transfer for wireline and wireless
broadband Internet-access and communications between different
regions. In order to support IPv6 inter-connectivity for other local
networks, all the routers in ChinaNet have been IPv6-enabled and
operate in IPv4/IPv6 dual-stack mode. Different from ChinaNet, CN2
is a MPLS-based network, which mainly focuses on service provisioning
to enterprise customers and some services with high-quality
requirements. CN2 has enabled 6VPE and 6PE in its equipment,
therefore, it can provide high-speed IPv6 data switching and IPv6 VPN
to enterprise customers.
Currently MANs mainly uses dual-stack approaches, due to the shortage
of IPv4 address, most users are allocated with private address by
BRAS/BNGs. From 2012, multiple types of transition technologies,
such as Dual-stack, DS-Lite, Lightweight 4over6, and IVI, were
Xie, et al. Expires January 8, 2021 [Page 4]
Internet-DraIPv6 development and current status of China Tele July 2020
evaluated in the field trial, this process is nearly in parallel with
that of standardization in IETF, and most of the transition
techniques were in the stage of draft then. In order to support
multiple transition techniques, the supportive system of MANs was
upgraded to support dynamic selection of transition approaches based
on the type of CPEs and availability of the resource in the network
locally. However, due to the fact that most transition techniques do
not gain commercial support in CPEs, MANs later adopted dual-stack
approach for household users, and CGN module has been installed in
BRAS/BNGs for private and public address translation.
Same to the MANs, EPC of LTE also runs in dual-stack mode. When IPv6
deployment in LTE begun in 2015, it was required to switch on the
IPv6 protocol in the user plane of EPC and each user was allocated
one /64 Prefix of IPv6 and IPv4 address simultaneously. It should be
noted that EPC network of LTE is constructed on the provincial basis,
and each province has a set of EPC network, so for a given province,
when IPv6 capability is turned on in the EPC, every user's UE in this
province can get IPv6 address unless it does not support IPv6. Since
IPv6 has good support in the UEs of LTE, IPv6 penetration rate of
mobile user is higher than that of wireline user.
IDC is a place to provide stable and broadband networks with high
performance computers as a service to their customers it is another
scenario for IPv6. As the largest IDC providers, China Telecom has
upgraded all its IDCs to support IPv6. In addition, China Telecom
also provides cloud services and products based on the cloud resource
pools located in different regions of China, currently more than 50
cloud products are IPv6-capable,e.g., Elastic virtual machine, ELB,
Cloud desktop, Elastic IP, GPU virtual machine, which makes it
possible to provide IPv6-based network-cloud-convergence services to
customers.
Regarding to the IPv6 interconnection with other carriers, China
Telecom has setup IPv6-BGP peers with domestic partners, e.g., China
Mobile, China Unicom and CERNET, and the total bandwidth reaches to
5.4 Tbps in 13 inter-connection points, and also setup IPv6 BGP
connections with some giant global ISPs.
5. IPv6 measurement
In order to see how broadly IPv6 is being used in China, a
measurement system was developed by CAICT (i.e., Chinese Academy of
Information and Communications Technology). All the major networks,
including those of China Telecom, participate in the measurement.
The metrics that can be measured include user penetration rate,
traffic volume, end-to-end performance, etc. The measurement has
been running continuously and the result can be presented in real
Xie, et al. Expires January 8, 2021 [Page 5]
Internet-DraIPv6 development and current status of China Tele July 2020
time.
From the measurement, it can be seen that the quantity of user who
are allocated IPv6 address has increased dramatically during the last
two years. However, compared with the quantity of user who are
allocated IPv6 address, the quantity of active user deserves more
attention, herein, the term of "active IPv6 user" refers to the user
who have at least one visit of IPv6 content within one month. Recent
measurement shows that the rate of active IPv6 users in Mobile
network is about 79 percent. However, this metric in wireline
network is about 30 percent, much lower than that of LTE network.
This difference is mainly caused by the low rate of IPv6-capble home
routers.
It should be noted that the data in this draft only shows the current
status, the measurement result changes over time.
6. Challenges
Although IPv6 has gained widely deployment in China Telecom and most
users have been allocated IPv6 addresses, several challenges still
face operators. Regarding to the usage of IPv6, traffic volume of
IPv6 is still much lower than that of IPv4, and the rates of IPv6
traffic of mobile network and wireline network are about 8.8 percent
and 2 percent respectively, it is supposed that this is mainly due to
the reasons below.
1. Low rate of IPv6 support in home CPEs: As a matter of fact, a
portion of home CPEs are not customized by operators. CPE
routers can be purchased from online shop and installed at home
without any allowance of operators, some types do not support
IPv6 at all. This factor makes it difficult to improve the
penetrate rate and IPv6 traffic. However, there is good news
that after realizing this problem, the IPv6 community has jointly
pushed the vendors of CPE router to improve IPv6 support in their
products.
2. Slow transition on contents' side:Compared with the transition of
network operators, the transition of content's side is relatively
slow. One reason is that service layer transition depends on the
IPv6 capability of low-layer infrastructure, such as CDNs and
IDCs; they are required to support IPv6 in advance. Another
reason behind this is that content providers are very concerned
about the end-to-end performance of the IPv6 networks, so even
though IPv6 has been implemented in their products, they are
still very cautious to switch from IPv4 to IPv6 in clients
software, and the IPv6 coverage is increased step by step based
on the result of performance test. One the other side, some OTTs
Xie, et al. Expires January 8, 2021 [Page 6]
Internet-DraIPv6 development and current status of China Tele July 2020
has taken bold step to use IPv6, for instance, the measurement
show that the rate of IPv6 traffic of Youku, which is one of the
largest video providers in China, is more than 70 percent.
Although Challenges lies ahead, China Telecom will persistently push
forward the deployment and utilization of IPv6. Take advantages of
ubiquitous IPv6 deployment, SRv6 field trial has been implemented in
several use cases, including MAN, Mobile transport network, anti-
DDOS, etc. Particularly, IPv6 will be planned to be used in new
scenarios, such as IOT and network-cloud-convergence, and the
transition to IPv6-only will be explored in the coming future.
7. Security Considerations
None.
8. Acknowledgements
During the long period, China Telecom's IPv6 deployment has received
strong support from lots of people, some of them are Xing Li, Fred
Baker, Latif Ladid, Zhenbin Li, Hui Tian, Shucheng Liu, Geoff Huston,
Dong Liu, Yan Ma, etc.
9. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC4787] Audet, F., Ed. and C. Jennings, "Network Address
Translation (NAT) Behavioral Requirements for Unicast
UDP", BCP 127, RFC 4787, DOI 10.17487/RFC4787, January
2007, <https://www.rfc-editor.org/info/rfc4787>.
[RFC6144] Baker, F., Li, X., Bao, C., and K. Yin, "Framework for
IPv4/IPv6 Translation", RFC 6144, DOI 10.17487/RFC6144,
April 2011, <https://www.rfc-editor.org/info/rfc6144>.
[RFC6333] Durand, A., Droms, R., Woodyatt, J., and Y. Lee, "Dual-
Stack Lite Broadband Deployments Following IPv4
Exhaustion", RFC 6333, DOI 10.17487/RFC6333, August 2011,
<https://www.rfc-editor.org/info/rfc6333>.
[RFC7219] Bagnulo, M. and A. Garcia-Martinez, "SEcure Neighbor
Discovery (SEND) Source Address Validation Improvement
(SAVI)", RFC 7219, DOI 10.17487/RFC7219, May 2014,
<https://www.rfc-editor.org/info/rfc7219>.
Xie, et al. Expires January 8, 2021 [Page 7]
Internet-DraIPv6 development and current status of China Tele July 2020
[RFC7596] Cui, Y., Sun, Q., Boucadair, M., Tsou, T., Lee, Y., and I.
Farrer, "Lightweight 4over6: An Extension to the Dual-
Stack Lite Architecture", RFC 7596, DOI 10.17487/RFC7596,
July 2015, <https://www.rfc-editor.org/info/rfc7596>.
[RFC7599] Li, X., Bao, C., Dec, W., Ed., Troan, O., Matsushima, S.,
and T. Murakami, "Mapping of Address and Port using
Translation (MAP-T)", RFC 7599, DOI 10.17487/RFC7599, July
2015, <https://www.rfc-editor.org/info/rfc7599>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", STD 86, RFC 8200,
DOI 10.17487/RFC8200, July 2017,
<https://www.rfc-editor.org/info/rfc8200>.
Authors' Addresses
Chongfeng Xie
China Telecom
China
Email: xiechf@chinatelecom.cn
Cong Li
China Telecom
China
Email: licong@chinatelecom.cn
Chenhao Ma
China Telecom
China
Email: machh@chinatelecom.cn
Quanxin Yuan
China Telecom
China
Email: yuanqx@chinatelecom.cn
Xie, et al. Expires January 8, 2021 [Page 8]