wdiff draft-fu-dmm-vcpe-models-00.txt draft-fu-dmm-vcpe-models-01.txt

Internet Engineering Task Force Q. Fu, Ed.
Internet-Draft China Mobile H. Deng
Intended status: Informational S. Gundavelli
Expires: January 2, 2016 Cisco
H. Deng China Mobile
July
Expires: April 21, 2016 October 19, 2015

Motivations, usecases and Models of VCPE
draft-fu-dmm-vcpe-models-00
draft-fu-dmm-vcpe-models-01

Abstract

This document introduces the concept of Virtual Customer Premises
Equipment (VCPE). Such concept was first proposed in Broadband Forum
(BBF) as Network Enhanced Residential Gateway (NERG). The VCPE concept is
the Home Agent (HA)
further expanded as not only referring to virtual CPE of residential
network, but all the Mobile Nodes (MN) attached virtual network and service functions shifted
from the customer side to the physical
CPE (pCPE). operator side. Deployment of VCPE in
some typical DMM (Distributed Mobility Management) scenarios brings
specific requirements and even protocol extension in DMM. In this
document, we will first explain the motivation and advantages of
VCPE. Three A usecases of VCPE in the community Wi-Fi deployment is
further discussed in
the enterprise network, the residential network, and so as to explain the Internet deployment of
Things (IoT) Network. Two VCPE in a DMM
scenario. Three models of field deployment of VCPE are discussed afterwards. The models of VCPE decompose
afterwards to indicate the Control Plane
(CP) possible CP/DP decomposition requirement
and the Data Plane (DP), which makes it easier for the
deployment of the distributed mobility model. protocol extension.

Status of This Memo

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Table of Contents

1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Motivation and Advantage of VCPE . . . . . . . . . . . . . . 3
4. Use case of VCPE . . . . . . . . . . . . . . . . . . . . . . 4
5. Models of VCPE Deployment . . . . . . . . . . . . . . . . . . 5
6. VCPE Deployment for Community Wi-Fi . . . . . . . . . . . . . 8
7. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . 8
7. 9
8. Informative References . . . . . . . . . . . . . . . . . . . 8 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9 10

1. Introduction

This document introduces the concept of VCPE. The concept of VCPE is
to shift most of the networking and service functionalities from the
customer side to the network side. In this way, the customer side's
equipment, that is the pCPE (Physical Customer Premises Equiptment),
can be simplified. The VCPE refers to one or a set of equipments at
the network side to execute the networking and service
functionalities used to be executed at the CPE. In such
architecture, the CPE can be a simple L2 switch, which is only
responsible for forwarding packets to a certain next hop. The
concept of VCPE was first introduced in BBF as NERG (WT-317), which
mainly focuses on shifting some of the functionalities of a
residential gateway to the operator's network, for enabling network
based features. The aim is to facilitate the deployment, maintenance
and evolution of both existing and new capabilities without adding
complexity to the RG and/or the home network.

Figure 1 shows the architecture of the pCPE and the VCPE. In this
architecture, the VCPE is the HA for the mobile nodes adhear to the
pCPE at the network side.

+---+ +-----+ +-----+
|MN1|====|pCPE1|================|VCPE1|
+---+ +-----+ +-----+

+-----+
|pCPE2|
+-----+

+---+

............... ..............
:Customer side: :Network side:
: +-----+ : : +-----+
|MN2|====|pCPE3|================|vCPE2|
+---+ :
: |pCPE |================|VCPE | :
: +-----+ : : +-----+ :
..............: .............:

Figure 1: VCPE Architecture

In this document, we would like to further propose such concept in
the following aspects:

(1) Motivation and advantages of VCPE.

(2) Usecases of VCPE. We propose three usecases, including the
enterprise network, the residential network, and the IoT (Internet A usecase of
things) network. VCPE in the community Wi-Fi is
explained in detail.

(3) Models of VCPE deployment. We propose two three models for the field
deployment of VCPE. Such models can be used for deployments in
multiple scenarios, including both residential network and enterprise
network.

2. Terminology

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].

3. Motivation and Advantage of VCPE

The motivation and advantage of introduting VCPE can be concluded as
follows:

(1) It will reduce greatly speed up the cost service launching period. Since
most of manufacturing the complicated functions are located at the VCPE in the
network side, operators have more power over services. Benefitting
from the recent NFV (Network Function Virtualization) and maintaining cloud
technologies, VCPE can be accomplished using SFC in the virtual
network, where different services can act as different VNFs (Virtual
Network Functions). Operators only need to add new VNFs on the VCPE
side to launch new services to the customers. In this way, Operators
can provide a variety of services through the network.

(2) It will reduce the cost of the pCPE. By shifting most of the
complicated functions from the customer's side to the operator's
side, the cost of the pCPE can be reduced significantly. Such
redunction can be remarkable in the enterprise network, since network
functions, such as Firewall and NAT(Network Address Translator) at
the customer side can be expensive. In the meantime, deployment of VCPE can also reducing the
OPEX of operators. Orders cost of on-site repair can be reduced because
upgrading tens of the simplicity thousands of the customer equiptments.

(2) It will avoid complicating the pCPE devices when providing value-
added L3-L7 services to the customers. Take the transport network as
example. Traditionally, pCPEs at the enterprise customer side are
simple L2 devices in the transport network. In order to meet the
requirements for value-added L3-L7 launching new services from the customers, the
pCPEs should can
be redesigned to become L3 or even more complicated
devices. Such devices will not saved, since only result in an increase of
manufacture and maintenance cost, and will also request addtional
efforts for frequent update to meet the constantly increased
requirements of the customers. Nevertheless, by utilizing software upgrade at the VCPE
achitecture, pCPE can remain to be a simple L2 device, which is only
responsible for L2 forwarding. In this way, frequent update of these
pCPEs side is not necessary, which will greatly decrease both CAPEX and
OPEX of the network operators. required.

(3) It will greatly speed up simplify the service launching period. maintainance of the pCPE. Since most of the
complicated functions functionalities are located at the VCPE in shifted to the network side, operators have more power over services. Benefitting
from the recent NFV (Network Function Virtualization) and cloud
technologies, VCPE
maintainance of the pCPE can be accomplished using SFC greatly simplified. On-line
maintainance is possible in lots of cases since the virtual
network, where different services can act as different VNFs (Virtual
Network Functions). Operators pCPE is only need to add new VNFs on the VCPE
side to launch new services to the customers. In this way, Operators
can provide a variety of services through L2
devices and can be considered transparent to the network. operators.

(4) It will provide user-define-network experience. By introducing
SFC concept into the VCPE, users can define his own service order and
sequence. Therefore, enterprise customers can enjoy the self-defined services
over the public network.

4. Use case of VCPE

The concept of VCPE can be used in multiple scenarios. In this
section, we will propose two use cases of VCPE, one in residential
network, and the other in the enterprise network.

(1) Use Case a usecase of VCPE in the Enterprise network.

Traditional enterprise network uses the tranport network access.
Multiple when deploying community
Wi-Fi.

The community Wi-Fi is a new service that operators provide to
leverage unused capacity on existing residential Wi-Fi infrastructure
to offer Wi-Fi network functions, including Firewall (FW) access to visitors and NAT, are
deployed at the enterprise customer's side. Such deployment not only
increases passers by near the cost of
neighbourhood. An operator can also use this excess capacity to
offer services to retail and roaming-parter operators' subscribers.
The residential subscribers accessing the equiptment at network from inside their
homes have prioritized access to the customer side, but also
makes it difficult Wi-Fi resources. The
residential Wi-Fi infrastructure is configured in a manner that
allows for both the enterprise customers a secure and the independent access channel to retain service
providers operating
quality, safety, and maintaining the functions.

By introducing VCPE into the transport network, functions such as FW privacy for both residential and NAT can be shifted visitor
customers. Roaming users are only allowed to use the aggregate Wi-Fi network or core network,
acting as VCPE at the service provider's side. Moreover, value-added
services can be provided. For example,
capacity that is not currently used by deploying a virtual Deep
Packet Inspection (vDPI), service providers can provide fine grained
data control to the enterprise customers.

(2) Use case of VCPE in the residential network.

In the residential network, traditionally, pCPE locates subscriber at home.

Basically, the
customer premises terminates wireless Access Point (AP) in the home network will provide
two networks: a private one for the home owner/subscriber, and connect a
community network for on-the-go subscribers passing through the LAN
neighborhood. Home users can have all of their Wi-Fi devices
(smartphone, tablet, etc.) automatically connect to the Internet or to some service platforms through the
broadband access private
network. With In the expansion of meantime users travel outside can connect to the broadband access
community network, and the development of the OTT (Over can roaming through different APs supporting
community Wi-Fi as he/she is moving. The Top) industry, the quantity
and requirements of addtional functions community Wi-Fi service is
a typical usecase of DMM.

Deploying community Wi-Fi on the pCPE increases rapidly.
By shifting most means upgrading tens of the complicated functions to VCPE, the cost
thousands of existing pCPE devices at the largely deployed CPE can be saved. customer side, which is not
cost-effective and may bring extra complexity for maintainance.
Therefore VCPE becomes an optimized solution for such deployment. In
such deployment, the meantime, deployment
of new features by service providers can be accelerated.

Taking PPPoE private users access as example. By shifting PPPoE client to VCPE, the pCPE can be a simple L2 device. In this case, VCPE takes (which is the
responsibility to initiate PPPoE request to BRAS once receiving
AP at home) as usual. The public users are roaming through different
pCPEs. The traffic flow from the customers. When receiving all goes though the certification tunnel from BRAS, VCPE will act as DHCP server by assigning IP address to the traffic generating port. Such approach can also be used for IPv6
upgrade,in which case VCPE can act as IPv6 DHCP relay.

(3) Use case of VCPE in pCPE to the IoT (Internet
VCPE. The deployment of Things) network. VCPE can also be used in the IoT network. So far, multiple wireless
communication standards, including Wi-Fi, Zigbee, Blue Tooth, community Wi-Fi sencario brings
specific requirement and
etc., exist for the connection of the IoT devices protocol extensions to the GW. DMM. The IoT
GW is responsible for decomposing the L2 packets from the devices,
composing them into L3 packets and transferring to the Internet
Server. Due to these various wireless communication standards,
multiple IoT GWs have to be deployed at users' home to support
different IoT devices. By shifting the packet transforming function
to VCPE, IoT GW can be a simple and unified L2 forwarding GW, while deployment
model of VCPE will support different standard stacks and its possible influence to DMM is responsible for
transforming packets further discussed
in the following different communication standards to
IP packets. section.

5. Models of VCPE Deployment

There are multiple models when deploying VCPE in use cases as are
discussed in the previous section. In this document, we conclude the
deployment of VCPE into two three models. In the first model, a logical
instance of VCPE is deployed in the cloud for each pCPE instance.
All traffic from pCPE goes through the vCPE. In the second model,
the VCPE is based on service chains attached to BNG. The classifier
on BNG puts
That is, the pCPE traffic through the correct set of service
functions. Both of these two models can easily introduce CP/DP
decompositon at the VCPE side, and the DMM protocol can be used.

Figure 1 and Figure 2 show the two models of VCPE deployment. For
the first model, logical instance of VCPE is deployed. Such logical
instance can be a seperate instance deployed before or after the BNG,
as is shown in Figure 1(a) and Figure 1(b). It can also be deployed
by upgrading the traditional BNG to include an 1:1 manner. All traffic
from pCPE goes through the functions of VCPE, as
is shown in Figure 1(c). vCPE.

+------+ +------+
| pCPE +--------+ +-----| VCPE |-----+
+------+ +------+ |
| +------+ ________
+------+ +--+---+ +-----+ +------+ +-+---+ |SFC in| / \
| pCPE +-----+ VCPE +---+ BNG +-----+WAN DC+---+ Internet |
+------+ +--+---+ +-----+ +------+ +-+---+ +------+ \________/
|
+------+ +------+ |
| pCPE +--------+ +-----| VCPE |-----+
+------+ +------+

Figure 1(a) 2: VCPE instance deployed before deployment model NO.1: Logical Instance of VCPE

In the second model, vCPE is modeled service function chains in Gi-
LAN. BNG

+------+
| knows how to classify the traffic from a given CPE with the
help of the control plane, and run it through the service chain. In
such model, the CP/DP interface should be used between the control
plane (which might be the controller) and the pCPE.

+----------+
+Controller|
+--+-------+
+CP/DP interface .......................
+ :VCPE :
+ +---+--+ : +-----------------\ :
++++ pCPE +--------+ :|SFP1:DPI->FW->NAT + :
+ +------+ | : +-----------------/ :
+ | : :
+ +------+ ________
+------+ +--+---+ +-----+ |SFC in| / \
| +--+--+ : +------------\ :
++++ pCPE +-----+ BNG +---+VCPE +-----+WAN DC+---+ Internet |
+------+ +--+---+ +-----+ +---+SFP2:FW->NAT + :
+ +------+ \________/ +--+--+ : +------------/ :
+ | : :
+ +------+ |
| : +--------\ :
++++ pCPE +--------+ : |SFP3:NAT + :
+------+ : +--------/ :
.......................

Figure 1(b) 3: VCPE instance deployed after deployment model NO.2: VCPE as SFC

The third model is almost the same with the second one, except that
the BNG

+------+
| is also CP/DP decomposed. In this model, The control plane
is composed of the controller of the pCPE +--------+
+------+ |
+--+---------+ +------+ ________ and the control plane of
the BNG. The CP/DP interface is used between the controller and the
pCPE, and between the control plane and the data plane of the BNG.
Both of model No.2 and No.3 may have specific requirement and protoco
extensions for the CP/DP interface due to the usecase of VCPE.

.................................
: Control Plane :
: +----------+ +------+ :
: +++++++Controller| |BNG +-----+ CP| :
: + +----------+ +--+---+ :
..+......................+......:
+ CP/DP interface + .......................
+ + :VCPE :
+ +---+--+ + : +-----------------\ :
++++ pCPE +-------+ + :|SFP1:DPI->FW->NAT + :
+ +------+ | |SFC in| / \ + : +-----------------/ :
+ | + : :
+ +------+ +-+----+-+ : +------------\ :
++++ pCPE +-----+ |VCPE | +---+WAN DC+---+ Internet | BNG DP +----+SFP2:FW->NAT + :
+ +------+ +-+------+ : +------------/ :
+ +-----+ | +------+ \________/
+--+---------+ : :
+ +------+ |
| : +--------\ :
++++ pCPE +--------+ +-------+ : |SFP3:NAT + :
+------+ : +--------/ :
.......................

Figure 1(c) VCPE instance deployed through upgrading BNG

Figure 2: 4: VCPE deployment model NO.1: Logical Instance of VCPE

For the second models, no logical instance exists as VCPE. NO.3: VCPE is
realized as a sequence SFC, with CP/DP
decomposition of service function chaining (SFC) in the WAN
DC. In this model, BNG is acting as the classifier of SFC. Such
classfication should be based on user profile, in which case, users
can define his own VCPE service.

SDN (Software Define Network) controllers can also be introduced in
the second third model. In which case, all of the pCPEs and the BNG data
plane (BNG-dp) (BNG DP) can be controlled by the SDN-controller (also acting
as the BNG control plane(BNG-cp)), as is shown in Figure 3. SDN-controller. When the
customer selects a set of services, the SDN-controller will inform
the pCPE and the BNG-dp BNG DP to direct the traffic flow to a certain SFC.
the Service Classification Function (SCF) is located in the BNG,
responsible for classifing traffic from different customer/network/
service. The SCF is controlled by the SDN-controller. When a packet
arrives, the SCF will ask the controller which Service Founction Path
(SFP) this flow should follow, and put corresponding SFC
encapsulation into the packet. The packet then goes into the service
founction region, and will be directed to different Service
Founctions (SF) based on the encapsulation.

+------+ ...............
| pCPE +--------+

.................................
: Control Plane :
: +--------------+ : VCPE
: +++++++SDN Controller|++ :
: + +--------------+ + :
..+......................+......:
+ CP/DP interface + .......................
+ + :VCPE :
+ +---+--+ + : +-----------------\ :
++++ pCPE +-------+ + :|SFP1:DPI->FW->NAT + :
+ +------+ | + : +----+ +-----------------/ :
+ | + : : +--+sfp1+-----------+
+ +------+ +--+---+ +-+----+-+ : | +----+ +------------\ : ___|____
|
++++ pCPE +-----+ BNG +----| +----+ DP +----+SFP2:FW->NAT + : / \
+ +------+ +--+---+ +-+------+ : +--+sfp2+------+ Internet |
| +------------/ :
+ | +----+ : \________/ :
+ +------+ | : | +----+ +--------\ : |
|
++++ pCPE +--------+ +-------+ : |SFP3:NAT + : +--+sfp3+-----------+
+------+ : +----+ +--------/ :
:.............:
.......................

Figure 3: 5: VCPE deployment model NO.2: NO.3: SFC realization of VCPE VCPE, with
SDN controller as control plane

6. VCPE Deployment for Community Wi-Fi

In this section, we will discuss about the VCPE deployment for
Community Wi-Fi in detail. In the following deployment, we assume
the VCPE is deployed following the third model we discussed in
section 5. That is, the VCPE is a bounch of SFCs at the operator
side behind the BNG. The pCPEs and BNG-DP are all controlled by a
mutual control plane. The FPC protocol is used between the control
plane and the pCPEs, and that and the BNG-DP.

As we discussed in section 4, Community Wi-Fi can be deployed with
the help of deploying VCPE. In order to provide the Community Wi-Fi
service, the pCPE should provide two SSIDs, one for the pubic Wi-Fi
users, and the other for the private Wi-Fi users. Packets from
different SSID are marked with different VLAN ID. The VCPE should
know of the corresponding relation between the SSID and the VLAN ID,
so as to provide distinguished services to the publice users and the
private users. For instance, the private users should experience a
better QoS than the publice ones. In the meantime, the private users
and the public users may choose different SFC in the VCPE. All of
these different services are classified based on the VLAN ID.

Such deployment requirs the FPC client to support the following task:

1) The FPC client should be able to set specific VLAN to each SSID.

2) The FPC client should be able to set the QoS for specific VLAN ID.

3) The FPC client should be able to inform the agent the specific SFC
for each VLAN ID.

4) The FPC client should be capable of instruct the agent to handle
the MN hand-over of the public Wi-Fi users.

In the meantime, such deployment requirs the FPC agent to support the
following task:

1) The FPC agent should be able to set specific VLAN to each SSID
following the command from the client.

2) The FPC agent should be able to set the QoS for specific VLAN ID
following the command from the client.

3) The FPC agent should be able to direct the traffic for specific
VLAN ID to a certain SFC following the command of the client.

4) The FPC agent should be able to handle the MN hand-over of the
public Wi-Fi users.

7. Conclusion

In this document, the concept of VCPE is illustrated in detail. The
basic concept of VCPE is to shift the complicated functions from the
pCPE at the customer side to the VCPE at the service provider side.
The motivation of such shifting can be concluded as providing quick
launched customer defined services, reducing the Capex and Opex of
the pCPE, and providing quick launched customer
defined services in simlify the meantime. Three maintainance of both pCPE and VCPE. A use
cases are of community Wi-Fi is proposed for VCPE, including scenarios in the enterprise network, the residential
network and the IoT network. Two which is a typical
scenario for DMM. Three models are then discussed for the field
deployment of VCPE.

7. And CP/DP interface is suggested to be utilized
in the deployment models.

8. Informative References

[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997. 1997,
<http://www.rfc-editor.org/info/rfc2119>.

Authors' Addresses

Qiao Fu (editor)
China Mobile
Xuanwumenxi Ave. No.32
Beijing
China

Email: fuqiao1@outlook.com

Sri Gundavelli
Cisco

Email: sgundave@cisco.com

Hui Deng
China Mobile
Xuanwumenxi Ave. No.32
Beijing
China

Email: denghui@chinamobile.com