Internet DRAFT - draft-meng-sfc-broadband-usecases
draft-meng-sfc-broadband-usecases
service function chain C. Xie
Internet-Draft China Telecom
Intended status: Standards Track W. Meng
Expires: April 9, 2016 C. Wang
ZTE Corporation
B. Khasnabish
ZTE TX, Inc.
October 7, 2015
service function chain Use Cases in Broadband
draft-meng-sfc-broadband-usecases-04
Abstract
This document discusses about service function chain use cases in
different scenarios of broadband network. The document provides
analysis of different solutions and also describes the suitable
scenarios that each solution may be deployed in.
Status of this Memo
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This Internet-Draft will expire on April 9, 2016.
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described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Convention and Terminology . . . . . . . . . . . . . . . . . . 5
3. Use cases . . . . . . . . . . . . . . . . . . . . . . . . . . 6
3.1. Internet Access from Homes . . . . . . . . . . . . . . . . 6
3.1.1. Native IPv4 Network or Native IPv6 Network . . . . . . 6
3.1.2. IPv4/IPv6 Coexist Network . . . . . . . . . . . . . . 7
3.2. Internet Access from Enterprises . . . . . . . . . . . . . 11
3.3. Internet Access from Campuses . . . . . . . . . . . . . . 12
3.4. Added-value Service Access . . . . . . . . . . . . . . . . 12
3.4.1. Destination Address Accounting(DAA) . . . . . . . . . 13
3.4.2. IPTV . . . . . . . . . . . . . . . . . . . . . . . . . 14
3.4.3. VoIP/MoIP . . . . . . . . . . . . . . . . . . . . . . 16
4. Considerations . . . . . . . . . . . . . . . . . . . . . . . . 17
4.1. Service Function Chain Symmetry . . . . . . . . . . . . . 17
4.2. Deploying consideration . . . . . . . . . . . . . . . . . 17
4.2.1. Standalone mode . . . . . . . . . . . . . . . . . . . 17
4.2.2. Directly connecting mode . . . . . . . . . . . . . . . 19
4.3. Pool consideration . . . . . . . . . . . . . . . . . . . . 21
4.4. NAT traversal . . . . . . . . . . . . . . . . . . . . . . 21
4.5. Unify home router . . . . . . . . . . . . . . . . . . . . 21
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 22
6. Security Considerations . . . . . . . . . . . . . . . . . . . 23
7. Normative References . . . . . . . . . . . . . . . . . . . . . 24
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 26
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1. Introduction
The object of SFC is trying to unload services from legacy devices in
traditional network and deal with such services through corresponding
service functions which are topologically independent from physical
devices.
As increasingly large number of customers, the possibility of
deployment SFC in broadband network seems emergency. And this
document aims to illustrate the possibly typical and unified service
function chains in Broadband Networks and analyze the possible
deployments of diverse service function chains in broadband network.
In figure 1, here outlines the possible SFC deployment architecture
in Broadband Networks. This architecture tries to simplify and unify
the services in CPEs and unloads the services from CPEs to the SFCs
in Access Networks to achieve virtual CPE functions. And as well,
extracts the services in BNASs and offloads the services from BNASs
to the SFCs in Barrier Networks to accomplish virtual BNAS functions.
As a result of that, the Internet Service Provider can manage and
maintain the whole Broadband Networks more flexibly.
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+-----------+ +-----------+
| Host1 | ... | HostN |
+-----+-----+ +-----+-----+
| |
+-----+-----+ +-----+-----+
| classifer | | classifer |
+-----+-----+ +-----+-----+
| |
|---------|---------|
|
+-------+---------+
| SFCs/vCPEs |
. +-------+---------+ .
. | .
+-------|---------+ +-------|---------+ +-------|---------+
|switch/classifier| |switch/classifier| |switch/classifier| ...
+-------|---------+ +-------|---------+ +-------|---------+
| | |
+---------------------|--------------------+
|
+------+------+
| SFCs/vBNASs |
+------+------+
|
--------|--------
/ | \
| Internet |
\ | /
--------|--------
Figure 1: SFC Architecture of Broadband Network
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2. Convention and 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].
The terms about SFC are defined in [I-D.ietf-sfc-problem-statement].
The terms about CGN/DS-Lite/Lightweight 4o6/MAP/NAT64 are defined in
[RFC6888]/[RFC6333]/ [I-D.ietf-softwire-lw4over6]/
[I-D.ietf-softwire-map]/ [RFC6146].
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3. Use cases
The following sections highlight some of the most common broadband
network use case scenarios and are in no way exhaustive.
3.1. Internet Access from Homes
Figure 2 illustrates an abstract architecture of broadband network,
including CPE sitting in home access network, BNAS as broadband
access network gateway,CR located in bone network and the Internet.
+---+ +------+ +-----+ +---------+
|CPE|------| BNAS |--------| CR |------| Internet|
+---+ +------+ +-----+ +---------+
Figure 2: Architecture of Broadband Network
Also, the Broadband Forum(BBF) is developing a study document(SD-
326), which aims to study market requirements and usecases for
Flexible Service Chaining. Except that, this document tries to
develop more typical usecases in Broadband Networks.
3.1.1. Native IPv4 Network or Native IPv6 Network
---------------------------------------------------------------------------->
+--- + +-------+ +-----+ +----------+
| | |DPI/DFI| | LB/ | |URL Filter|---|
|--| UM |---| /Qos |---| FRR |---| /FW/PC | |
| +----+ | +-------+ | +-----+ | +----------+ |
+---+ +------+ | | | +-----+ +---------+
|CPE|--| BNAS-|-------|-----------|---------|-------------| CR |-----| Internet|
+---+ +------+ +-----+ +---------+
Figure 3: Native IPv4 Network or Native IPv6 Network
Figure 3 shows possible deployment of SFC in native IPv4 network or
native IPv6 network. As UM(users management) service, which is the
main service of BNAS device in traditional network, consumes large
memory and resources, it seems reasonable to decouple UM service from
legacy BNAS device and treat it as a service node , which may include
DHCP,AAA functions and some other functions related to users
management. And what!_s more, only users subscription messages
(protocol messages) go through UM service. Once a user is approved
by UM service, the following data flow of this user go through the
other service function chain which is assigned to this data flow.
'BNAS-' means some functions have been unburdened from traditional
BNAS,such as user management,Qos,Load Balance and so forth.
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Given that SFC is applied in Broadband network, the main SFs may
cover: User Management, DPI, DFI, Qos, Load Balance, Fast Reroute,
URL Filter,Firewall,Parental Control and so forth. And the possible
order is not as strict as above. The upstream/downstream traffic may
go through different permutations and combination of these SNs. For
example:
SFC1: UM
This SFC stands for the process of subsribers!_ log-in and log-out.
All the broadband subscribers!_ log-in messages and log-out messages
need go through this SFC. After approved by this SFC, then the users
flow can access the Internet or other services.
SFC2: Qos
This SFC shows some bandwidth restrictions or several priority-based
schedules are applied to this approved subscriber. Almost each home
subscriber has a corresponding subscribed bandwidth, different
services from a home have distinctive priority as well. As a result,
this is a basic SFC used in internet access from homes.
SFC3: Qos--LB
This SFC extends SFC2, which utilizes load balance to offload
approved subscribers!_ flow from an overload path. This is also a
typical scenario in broadband network, especially in metropolitan
area network.
SFC4: Qos--LB--URL Filter
Based on SFC3, this SFC gives extra restrictions to the content that
the approved subscriber wants to access.
SFC5: Qos--Parental Control
This is similar to SFC4,except there is no Load Balance. Another
difference is that SFC5 offers some restrictions to downstream
traffic in terms of content. SFC5 allows some legal or appropriate
contents to flow to subscribers, while some illegal or inappropriate
contents are blocking.
3.1.2. IPv4/IPv6 Coexist Network
As showed below in figure 4, the main difference between IPv4/IPv6
native network and IPv4/IPv6 coexist network is whether there exists
a NAT funtion. Although in IPv4 native network, there maybe exist
NAT44 function as a result of limited IPv4 address, we try to put
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this scenario together with other IPv6 transition scenarioes in this
section and discuss them in detail.
---------------------------------------------------------------------------->
+--- + +-------+ +-----+ +----------+
| | |DPI/DFI| | LB/ | |URL Filter|---|
|-----|NAT |---| /Qos |---| FRR |---| /FW/PC | |
| +----+ | +-------+ | +-----+ | +----------+ |
+---+ +------+ | | | +-----+ +---------+
|CPE|--| BNAS-|---------|-----------|---------|-------------| CR |---| Internet|
+---+ +------+ +-----+ +---------+
Figure 4: IPv4/IPv6 Coexist Network
Whether NAT stands for NAT44 or NAT64 or NAT46 depends on the the
Internet Server Provider. It may be NAT44, which reflects the
communication between IPv4 private customer and IPv4 public server.
Or it may be NAT64, which means the communication between IPv6
customer and IPv4 Server. And where NAT is deployed is the
preferance of the Internet Server Provider as well. It may be
besides BNAS,which stands for distributed deployment, or besides
CR,which represents central deployment.
Above figure 4 just gives a simple example of a possible deployment
position in distributed deployment scenario. Actually, there are
some other complicated IPv6 transition scenarioes . And this section
tries to give some typical examples in IPv4/IPv6 coexist network, and
conclude a feasible SFC architecture in IPv4/IPv6 coexist network.
Also, in the following sections, the other SFs emphasized in section
3.1.1 are not highlighted, just try to keep the diagram simple and
suitable for the draft's specification.
3.1.2.1. NAT44
Figure 5 illustrates a simple NAT44 scenario how SF-NAT is deployed
and how SF-NAT may work.
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.
:
|
............... |
External realm |
ISP network--> |-------------+
| ++---|----++
| | SF-NAT44 |
| ++---|----++
|-------------+
++--|----+
........... | BNAS- |
Internal realm ++------++
| |
ISP network--> | |
| |
++------++ ++------++
| CPE1 | | CPE2 | etc.
++------++ ++------++
Figure 5: NAT44
In distributed broadband networks, SNs may be deployed beside BNAS.
These SNs may contain or logically connect to SF-NAT and other
service functions such as UM,QOS,Load Balance,etc.
Here gives an example of possible SFC in IPv4/IPv6 coexist network,
which combines NAT function with the service functions in native
IPv4/IPv6 network.
SFC6: Qos--NAT--LB--URL Filter
SFC6 combines NAT function with SFC4, and represents the classical
scenario in IPv4/IPv6 coexist network. After customers have
subscribed, apply subscriber-based Qos policy, then transform IPv4/
IPv6 address into IPv4 address, and do five-tuple load balance for
the outbound traffic.
At last, monitor the outbound traffic and decide whether to permit
them to the internet or block them.
After the first packet of an outbound flow has been processed by this
SFC, this SFC can do SFP optimization to bypass NAT service function
to improve the experience of this subscriber. Then, for the
following packets of this outbound flow, the SFF connects to NAT
service function can forward them according to the forwarding table
which is derived from the NAT service function.
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As for the inbound flow of this subscriber, there exists an open
issue: how the inbound flow is steered to the same NAT service
function or the same SFF which connects to the same NAT service
function.
3.1.2.2. DS-Lite
Figure 6 describes a scenario of DS-lite, which completes IPv4
communication between IPv4 private customer and IPv4 server across
IPv6 network through tunnels. And the main principle of DS-Lite is
to encapsulate IPv4 packets in IPv6 Header and forward this IPv4-in-
IPv6 packets to CGN device and enforce NAT function in CGN device.
Generally, CGN device resides in BNAS device.
+-----------+
| IPv4 Host |
+-----+-----+
|
+---------|---------+
| CPE- |
+---------|---------+
+-----------------+
| +-----|--------+
| | SF-Dslite-Enc|
| +-----|--------+
+-----------------+
|||
|||<-IPv4-in-IPv6 softwire
|||
+--------|||--------+
| BNAS- |
+--------|||--------+
+----------------------+
| +----------|----------+
| | SF-Dslite-Dec |
| | SF-NAT |
| +----------|----------+
+-----------------+
|
|
--------|--------
/ | \
| IPv4 Internet |
\ | /
--------|--------
Figure 6: DS-Lite
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SFC7: Dslite-Enc---Dslite-Dec---NAT---LB---URL Filter
When the outbound flow are received by the CPE, the CPE sends them to
a specific classifier which determines the flow should be forwarded
directly or dealed with DS-Lite process. if the flow should be dealed
with DS-Lite process, then the classifier sends the datagram within
service header encapsulation to Softwire-SN which contains SF-Dslite-
Encapsulation instance. In this instance, it fulfils DS-Lite
encapsulate and then encapsulates overlay header and forwards this
flow to nexthop in the traditional network.
Next, the BNAS- receives the processed flow, the BNAS- sends them to
a classifier and finds they are legal flow and need to be dealed with
DS-Lite process. then, this flow are forwarded to SF-Dslite-
Decapsulation to decapsulate DS-Lite encapsulation. And as well,
forwarded to SF-NAT to create and maintain the NAT mapping table for
DS-Lite subscriber. SF-Dslite-decapsulation and SF-NAT can reside in
one service function or two different service functions. After that,
completes the subsequent SFs.
In other words, BNAS-,itself, would decouple DS-lite-related
functions to specific service function(s). What!_s more, if SFP
optimization function is enabled, BNAS- acts as SFF which connectes
to SF-NAT, and derives the NAT/forwarding table from SF-NAT and
bypasses SF-NAT to improve the experience of this subscriber.
If deploy SFC7 in this scenario, there also exists a consideration:
how to address the relationship between the access side SFC domain
and the network side SFC domain. If they are deployed in two
different SFC domain, how to cooperate between the SF-Dslite-
Encapsulation service function and SF-Dslite-Decapsulation service
function. On the other hand, if they are deployed in one big SFC
domain, it seems more feasible to carry out this SFC7.
3.2. Internet Access from Enterprises
------------------------------------------------------------------------------------>
+-------+ +-----+ +----------+
|DPI/DFI| | LB/ | |URL Filter|---|
+-----+ |----| /Qos |---| FRR |---| /FW/PC | |
|host1|--| +----------+ | +-------+ | +-----+ | +----------+ |
+-----+ | |URL Filter| +-----+ | | +-----+ +---------+
---| /FW/PC |--| SR- |-----------|---------|-------------| CR |---| Internet|
+-----+ | +----------+ +-----+ +-----+ +---------+
|host2|--|
+-----+
Figure 7: Internet access from enterprises
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Internet access from enterprises is another network service. They
lease some ports or even some devices from Internet Server Providers.
In addition to internal s service functions which are situated in the
internal enterprise network, there maybe deploy many external ISP!_s
service functions which are sitted on the way to the internet. -.And
what!_s more, there maybe deploy IPsec along with VPN users for the
sake of the security of enterprise network.
Internal service functions may include: Firewall, NAT function, etc.
As for external service functions deployed by ISP, typical service
functions are VPN, like L2VPN,L3VPN,IPsec,IPsec VPN etc.
Conventionally, there is a NAT function residing on SR, converting
VPN traffic to public traffic to access the internet.
In some cases, service providers need to assign differentiated
services to VPN users. In other words, different VPN users may go
through differentiated SFC. But, VPN traffic are all encapsulated in
outer MPLS header or some other transport headers, how the public
network elements classify them to different SFCs? At this time,
there maybe need create a mapping between VPN ID/VPN Name and
corresponding SFC on the service provider edge device.
Other external service functions involved in Internet access from
enterprise network maybe similar to home network, for example,
DPI,DFI,Qos,Load Balance, URL Filter,Firewall,Parental Control and so
on.
SFC8: URL Filter--FW---NAT---Qos---Load Balance----FW
Here, you may see two FW functions. One is in the inner of
enterprise, which represents the URL constrains from the perspective
of enterprise. While the other one is sitted in the ISP network, out
of the inner enterprise, and stands for the URL restrictions from the
standpoint of ISP.
3.3. Internet Access from Campuses
TBD
3.4. Added-value Service Access
To promote their primary service, ISP try to provide value-added
services to add value to the standard service offering. Here maybe
focus on some significant value-added services in broadband network
such as IPTV,VOIP,etc.
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3.4.1. Destination Address Accounting(DAA)
Figure 8 illustrates a possible deployment of DAA funtion in
broadband network.
+-----+
|host1|--|
+-----+ | +-------+ +----------+ +-----+ +---------+
--| CPE |---| BRAS+DAA |------| CR |---| Internet|
+-----+ | +-------+ +----------+ +-----+ +---------+
|host2|--|
+-----+
Figure 8: DAA Deployment in broadband network
In this diagram, DAA assists BRAS to accomplish finer-granularity
outbound filter or/and inbound filter based on destination IP
address. But,in central deployment scenario of DS-Lite, there is a
IPv4-in-IPv6 tunnel from CPE to CR. As a result of that, BRAS cannot
identify the true IPv4 destination address in this IPv4-in-IPv6
packets. And then, BRAS cannot enforce DAA function to manage the
subscriber more flexibly.
SFC9: DAA----Dslite-Enc----Dslite-Dec----NAT
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+-----------+ +-----------+
| Host1 | | Host2 |
+-----+-----+ +-----+-----+
| |
+-----|-----+ +-----|-----+
| CPE2- | | CPE2- |
+-----|-----+ +-----|-----+
| |
|---------|---------|
|
+-------|---------+
| SF-DAA |
+-------|---------+
|
+-------|---------+
| SF-Dslite-Enc |
+-------|---------+
|
|||
|||<--softwire
|||
+--------|||--------+
| CR |
+--------|||--------+
+----------------------+
| +----------|-----+
| | SF-Dslite-Dec |
| | SF-NAT |
| +----------|-----+
+----------------------+
|
|
--------|--------
/ | \
| Internet |
\ | /
--------|--------
Figure 9: DAA + Softwire Deployment in broadband network
3.4.2. IPTV
Figure 10 illustrates a possible deployment of IPTV network via SFC.
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<----------------------------------------------------
+----+
|STB1|-------|
+----+ |
|
+----+ +-------+ +------+
|STB2|---| BNAS1-|----| Qos1 |---------|
+----+ +-------+ +------+ |
| |
+----+ | |
|STB3|-------| |
+----+ |
+---------+ +-----+
+----+ | DPI/DFI |-----| CDN |
|STB4|-------| +---------+ +-----+
+----+ | |
| |
+----+ +-------+ +------+ |
|STB5|---| BNAS2-|----| Qos2 |---------|
+----+ +-------+ +------+
|
+----+ |
|STB6|-------|
+----+
Figure 10: IPTV network via SFC
IPTV is a IP multicast service, in which multi-subscribers should
receive the same traffic from the multicast source like Content
Distribution Network. Supposed there are six IPTV subscribers, from
STB1 to STB6, they are located in different districts and they all
need to receive traffic from Program 1. A possible SFC abstract here
is :
SFC10: DPI--Qos1
|---Qos2
In SFC10, as for the inbound traffic, there are two different
outputs, Qos1 and Qos2. Firstly, traffic from multicast source go
through DPI, which used for detecting whether the multicast traffic
are legal or unmalicious. After that, legal traffic propagate to
different Qos, and next, each goes through different BNAS- to
different STB subscirbers separately.
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3.4.3. VoIP/MoIP
TBD
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4. Considerations
4.1. Service Function Chain Symmetry
A complete end-to-end access in broadband network should consist of a
set of service function instances in a specific order. Such as:
4.2. Deploying consideration
4.2.1. Standalone mode
In broadband networks, service function components are hanging next
to routers such as CPEs/BNASs/CRs. All traffics would be received
and steered by routers. Routers send the traffic to classifier in
which traffic that matches classification criteria is forwarded along
a given SFP to realize the specifications of an SFC.
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+-----------+
| Host |
+-----+-----+
|
|
+---------|---------+ +-------------------+
| | | ------------- |
| CPE -----> | SFP | |
| <----- -------------- |
+---------|---------+ +-------------------+
|
|
--------|-------
/ | \
| ISP core network |
\ | /
------- | -------
|
|
+---------|---------+ +-------------------+
| | | ----------- |
| BNAS |----> | SFP | |
| <----| ----------- |
+---------|---------+ +-------------------+
|
|
--------|--------
/ | \
| Internet |
\ | /
--------|--------
Figure 11: Standalone mode
Take DS-Lite CGN for example.
Outbound traffic:
In the example shown in Figure X, a datagram received by the CPE from
the host at address 10.0.0.1, using TCP DST port 10000, will be
translated to a datagram with IPv4 SRC address 192.0.2.1 and TCP SRC
port 5000 in the Internet.
When the datagram 1 is received by the CPE, the CPE sent it to a
specific classifier which determines the datagram should be forwarded
directly or dealed with DS-Lite process. Then the classifier sends
the datagram within service header encapsulated to the first element
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of SFP. SF-SOFTWIRE encapsulates the datagram in another datagram
(datagram 2) and forwards it BACK to CPE over the softwire. The
datagram 2 would be sent to the Dual-Stack Lite carrier-grade NAT by
CPE.
When the BNAS receives datagram 2, the BNAS sends it to a classifier
and find it need to be dealed with DS-Lite process. Then the
classifier send the datagram within service header encapsulated to
the first element of SFP.
SF-SOFTWIRE decapsulates the datagram 2 to datagram 1 and forwards it
SF-NAT, which determines from its NAT table that the datagram
received on the softwire with TCP SRC port 10000 should be translated
to datagram 3 with IPv4 SRC address 192.0.2.1 and TCP SRC port 5000.
The translated datagram would be also sent back to BNAS for next
forwarding.
Inbound traffic:
Figure x shows an inbound message received at the classifer. When
the BNAS receives datagram 1, the BNAS sends it to a classifier.
Then the classifier sends the datagram within service header
encapsulated to the first element of SFP. SF- NAT looks up the IP/
TCP DST information in its translation table. In the example in
Figure 3, the NAT changes the TCP DST port to 10000, sets the IP DST
address to 10.0.0.1, and it will be sent back to BNAS to forwards the
datagram to the softwire. The SF-SOFTWIRE of the CPE decapsulates
the IPv4 datagram inbound softwire datagram and forwards it to the
host.
4.2.2. Directly connecting mode
There is another mode to deploy service function components. In
broadband home networks, service function components are directly
connected to the network. They are connected straight to a BNAS or
Routers.
Under this scenario, it seems like more costly than standalone mode
during transition period.
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| +-----------+
out | Host |
| +-----+-----+
v |
+---------|---------+ +-------------+
| |-out->classifier A |
| | +------|------+
| CPE | |
| | |
| | out
+---------/\--------+ |
|| |
+<===== in =====+------v------+
| |
| SFP A |
| |
+<----- out-----+------/\-----+
| ||
+---------v---------+ ||
| | ||
| | ||
| BNAS | ||
| | +------||-----+
| |==in=>classifier B |
+---------|---------+ +-------------+
--------|-------- /\
/ | \ ||
| METRO NETWORK | in
\ | / ||
---------^--------
.
.
+---------+---------+
| |
| | +-------------+
| CR | | SFP N |
| | +-------------+
| |
+-------------------+
Figure 12: Directly connecting mode
Take NAT44 for example.
Outbound traffic:
For directly connecting mode, the difference in dealing with traffic
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is whether the network steer the traffic loopback. That means
service function node could send datagrams directly to the next hop.
For example, when the outbound datagram is received by the BNAS and
processed by classifer A and SF-NAT which forward the processed
datagram straight next to router.
Inbound traffic:
It is quite similar with the process of dealing with outbound
traffic. when the inbound datagram is received by the router and
processed by classifer B and SF-NAT which forward the processed
datagram straight next to NAT BNAS.
4.3. Pool consideration
In traditional networks, pools are configured in router one by one.
Pool configuration means these IP addresses in each pool MUST be
advertised for creating forward routing path to ensures that the
message is routed to the correct target, especially to inbound
traffic. Thus, pool location is a problem we must face to in SFC
framework.
In standalone mode shown in figure 6, pool could be configured in the
classifier beside gateway and advertised by the gateway itself. The
classifier would assign IP addresses to service functions for
creating mapping table. Both-bound traffic should be forward to
gateway first and then for NAT treatment in relative service function
components.
In Directly connecting mode shown in figure 7, pool could be
configured in classifier B and advertised by classifier B for
creating inbound routing path.
There is a mechanism to manage the address pools centrally. Pools
could be assigned to classifiers by management server which is
handled by Operators centrally.
4.4. NAT traversal
TBD
4.5. Unify home router
TBD
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5. IANA Considerations
This memo includes no request to IANA.
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6. Security Considerations
TBD
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7. Normative References
[I-D.ietf-sfc-problem-statement]
Quinn, P. and T. Nadeau, "Service Function Chaining
Problem Statement", draft-ietf-sfc-problem-statement-13
(work in progress), February 2015.
[I-D.ietf-softwire-lw4over6]
Cui, Y., Qiong, Q., Boucadair, M., Tsou, T., Lee, Y., and
I. Farrer, "Lightweight 4over6: An Extension to the DS-
Lite Architecture", draft-ietf-softwire-lw4over6-13 (work
in progress), November 2014.
[I-D.ietf-softwire-map]
Troan, O., Dec, W., Li, X., Bao, C., Matsushima, S.,
Murakami, T., and T. Taylor, "Mapping of Address and Port
with Encapsulation (MAP)", draft-ietf-softwire-map-13
(work in progress), March 2015.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/
RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC2865] Rigney, C., Willens, S., Rubens, A., and W. Simpson,
"Remote Authentication Dial In User Service (RADIUS)",
RFC 2865, DOI 10.17487/RFC2865, June 2000,
<http://www.rfc-editor.org/info/rfc2865>.
[RFC6052] Bao, C., Huitema, C., Bagnulo, M., Boucadair, M., and X.
Li, "IPv6 Addressing of IPv4/IPv6 Translators", RFC 6052,
DOI 10.17487/RFC6052, October 2010,
<http://www.rfc-editor.org/info/rfc6052>.
[RFC6146] Bagnulo, M., Matthews, P., and I. van Beijnum, "Stateful
NAT64: Network Address and Protocol Translation from IPv6
Clients to IPv4 Servers", RFC 6146, DOI 10.17487/RFC6146,
April 2011, <http://www.rfc-editor.org/info/rfc6146>.
[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,
<http://www.rfc-editor.org/info/rfc6333>.
[RFC6519] Maglione, R. and A. Durand, "RADIUS Extensions for Dual-
Stack Lite", RFC 6519, DOI 10.17487/RFC6519,
February 2012, <http://www.rfc-editor.org/info/rfc6519>.
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[RFC6888] Perreault, S., Ed., Yamagata, I., Miyakawa, S., Nakagawa,
A., and H. Ashida, "Common Requirements for Carrier-Grade
NATs (CGNs)", BCP 127, RFC 6888, DOI 10.17487/RFC6888,
April 2013, <http://www.rfc-editor.org/info/rfc6888>.
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Authors' Addresses
Xie Chongfeng
China Telecom
Room 502, No.118, Xizhimennei Street
Beijing
China
Email: xiechf01@gmail.com,xiechf@ctbri.com.cn
Wei Meng
ZTE Corporation
No.50 Software Avenue, Yuhuatai District
Nanjing
China
Email: meng.wei2@zte.com.cn,vally.meng@gmail.com
Cui Wang
ZTE Corporation
No.50 Software Avenue, Yuhuatai District
Nanjing
China
Email: wang.cui1@zte.com.cn
Bhumip Khasnabish
ZTE TX, Inc.
55 Madison Avenue, Suite 160
Morristown, New Jersey 07960
USA
Email: bhumip.khasnabish@ztetx.com
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