Internet DRAFT - draft-wei-sfc-mobile-consideration

draft-wei-sfc-mobile-consideration



 



INTERNET-DRAFT                                                     X.Wei
Intended Status: Informational                       Huawei Technologies
Expires: January 1, 2015                                   June 30, 2014



            Interaction between SFC network and 3GPP network
                 draft-wei-sfc-mobile-consideration-00 


Abstract

   This document provides a discussion of how SFC (Service Function
   Chain) domain could interact with carrier network to provide network
   service for traffic. Here LTE (Long Term Evolution) network is used
   as an example of carrier network for discussion.


Status of this Memo

   This Internet-Draft is submitted to IETF in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups.  Note that
   other groups may also distribute working documents as
   Internet-Drafts.

   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."

   The list of current Internet-Drafts can be accessed at
   http://www.ietf.org/1id-abstracts.html

   The list of Internet-Draft Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html


Copyright and License Notice

   Copyright (c) 2014 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
   (http://trustee.ietf.org/license-info) in effect on the date of
 


X.Wei                   Expires January 1, 2015                 [Page 1]

INTERNET DRAFT     Re-classification analysis in SFC       June 30, 2014


   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.



Table of Contents

   1  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . .  3
     1.1  Terminology . . . . . . . . . . . . . . . . . . . . . . . .  4
   2.  Interaction between LTE network and SFC domain . . . . . . . .  4
     2.1  Interaction model . . . . . . . . . . . . . . . . . . . . .  4
     2.2  Information exchange  . . . . . . . . . . . . . . . . . . .  6
   3  IANA Considerations . . . . . . . . . . . . . . . . . . . . . .  6
   4  Security Considerations . . . . . . . . . . . . . . . . . . . .  6
   5  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . .  6
   6  References  . . . . . . . . . . . . . . . . . . . . . . . . . .  6
     6.1  Normative References  . . . . . . . . . . . . . . . . . . .  6
     6.2  Informative References  . . . . . . . . . . . . . . . . . .  7
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . .  7

























 


X.Wei                   Expires January 1, 2015                 [Page 2]

INTERNET DRAFT     Re-classification analysis in SFC       June 30, 2014


1  Introduction

   Different kinds of network Service Function (SF) have been deployed
   in current network to provide network service for traffic. But
   current SF deployments are tightly coupled to network topology and
   physical resources, and this limits the ability of an operator to
   introduce new services and/or service functions. To overcome the
   disadvantages of current SF deployments, flexible SFC (Service
   Function Chain) is under discussion in IETF [SFC PS].

   Though SFC domain is typically deployed by the owner of carrier
   network, here we treat SFC domain and carrier network as two separate
   network domain. A typical relationship between carrier network and
   SFC domain is shown in Figure 1. When network traffic goes through
   SFC domain, the SFC domain needs to know how to steer the traffic,
   i.e. which service chain the traffic should pass. The carrier network
   and SFC domain should interact properly in order to provide network
   service to traffic. 


   +---------------+  traffic  +----------+  traffic--------+
   |Carrier Network| <=======> |SFC domain| <=====>|Internet|
   +---------------+           +----------+        +--------+

      Figure 1 Relationship between carrier network and SFC domain

   LTE (Long Term Evolution) network [TS23.401] is standardized by 3rd
   Generation Partnership Project (3GPP), the basic architecture of LTE
   network is shown in Figure 2, three network entities including
   eNodeB, SGW and PDN-GW form the data path for user's traffic from UE
   to IP service network, and MME (Mobility Management Entity) acts as a
   central control point of the network. 


                                                             +--------+
                                                             |   IP   |
                        S1-MME  +-------+  S11               |Networks|
                      +----|----|  MME  |----|----+          +--------+
                      |         |       |         |               |SGi 
                      |         +-------+         |      S5/      |    
   +----+ LTE-Uu +-------+ S1-U                +-------+  S8  +-------+
   |UE  |----|---|eNodeB |---|-----------------| SGW   |--|---|PDN-GW |
   |    |========|=======|=====================|=======|======|       |
   +----+        +-------+                     +-------+      +-------+


                Figure 2 Basic LTE network architecture
   LTE network connects to IP service network through SGi interface
 


X.Wei                   Expires January 1, 2015                 [Page 3]

INTERNET DRAFT     Re-classification analysis in SFC       June 30, 2014


   [TS29.061].

   Gi-LAN service area is presently used by mobile network operator to
   differentiate their services to their subscribers; mobile network
   operator could deploy any kinds of SFs, e.g. Firewall, video
   optimizer, NAT (Network Address Translator), to provide network
   service for user's traffic. 


   +-----------+ SGi      +------+          +-----------+
   |LTE network| <======> |Gi-LAN|<========>|IP Networks|
   +-----------+          +------+          +-----------+
                    Figure 3 Gi-LAN for LTE network

   This document use LTE network as an example to illustrate how carrier
   network and SFC domain could cooperate to provide network service to
   traffic.

1.1  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 RFC 2119 [RFC2119].

   SFC domain: or SFC network, a network that implements SFC.

2.  Interaction between LTE network and SFC domain

   In this section, we will discuss how SFC domain could provide network
   service for traffic in LTE network.

2.1  Interaction model

   Before the discussion of interaction between LTE network and SFC
   domain, we first introduce the concept of Logical Service Function
   Chain (LSFC) and Physical Service Function Chain (PSFC). LSFC is a
   service function chain which is consisted of a list of SF type, and
   no specific SF instance is included in LSFC. 

   PSFC is a service function chain which is consisted of a list of SF
   instance, so PSFC could be viewed as an instance of LSFC. Considering
   of the requirements of load balance, there could be more than one
   instance for one type of SF, so a LSFC could be mapped into one or
   more PSFC.

   LSFC stands for a requirement of service function chain for certain
   traffic, and PSFC is a physical implementation that satisfies the
   requirement.
 


X.Wei                   Expires January 1, 2015                 [Page 4]

INTERNET DRAFT     Re-classification analysis in SFC       June 30, 2014


   When we take LTE network and SFC domain as two separate domains, LTE
   network plays the role of producing network service requirements and
   SFC domain plays the role of providing network service for LTE
   network's traffic.

   An overview of interaction between LTE network and SFC domain is
   depicted in Figure 4. LTE network creates LSFC for traffic and sends
   the LSFC to SFC domain, and then SFC domain is in charge of
   translating LSFC to PSFC. 

   Besides LSFC, additional information such as subscriber ID, that
   might be used but could not be accessed directly by SFC domain, will
   also be conveyed in service chain request procedure. 

              service chain request           
          +----------------------------+      
          |                            |      
          |                            |      
   +------|----+    traffic       +----V-----+
   |LTE Network| <==============> |SFC domain|
   +-----------+                  +----------+

  Figure 4 Overview of Interaction between LTE network and SFC domain

   There are sorts of information that could be used in creating of
   LSFC:

   - Mobile user's subscription information. For example, the network
   operator could provide video optimization service for gold and silver
   user's video traffic, but not for bronze user's traffic.
   - Network status information. For example, the radio access type that
   the mobile user currently attached to or the network congestion level
   could affect the choice of video optimizer for video traffic.
   - Agreement between content provider and network operator. Content
   provider, e.g. YouTube, could rent TCP optimization or video
   optimization function for its traffic, so for the traffic of content
   provider that has service agreement with network operator certain
   service function could be implemented. 
   - Application Characteristics. Application characteristics play very
   important role in creating service chain for the traffic, different
   kinds of application traffic, such as Web application and video
   application, would definitely go through different service chain.
   - QoS information of the service. QoS information of LTE network
   traffic could affect the choice of specific SF.

   Per operator's consideration, the combination of different
   information can be used in creating LSFC for the traffic. 

 


X.Wei                   Expires January 1, 2015                 [Page 5]

INTERNET DRAFT     Re-classification analysis in SFC       June 30, 2014


2.2  Information exchange

   This sub-section discusses what information elements should be
   conveyed in service chain request procedure from LTE network to SFC
   domain as depicted in Figure 4.

   As discussed in sub-section 2.1, LSFC will be conveyed in service
   chain request.
   +-----------+---------------------------------------------------+
   | Match rule| To identify which traffic the LSFC is specific to.|
   +-----------+---------------------------------------------------+
   | LSFC      | To specify network service function chain that    |
   |           | will act on the traffic.                          |
   +-----------+---------------------------------------------------+
   | Additional| SFC related auxiliary information such as User's  |
   | info      | Subscriber ID.                                    |
   +-----------+---------------------------------------------------+





3  IANA Considerations

   This document requires no requirement for IANA.

4  Security Considerations

   Security related issues is not involved.

5  Acknowledgments

   Many thanks to John Kaippallimalil and Chunshan Xiong (Sam) for their
   valuable comments.

6  References

6.1  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC6241]  Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
              and A. Bierman, Ed., "Network Configuration Protocol
              (NETCONF)", RFC 6241, June 2011.

   [RFC6733]  Fajardo, V., Ed., Arkko, J., Loughney, J., and G. Zorn,
              Ed., "Diameter Base Protocol", RFC 6733, October 2012.
 


X.Wei                   Expires January 1, 2015                 [Page 6]

INTERNET DRAFT     Re-classification analysis in SFC       June 30, 2014


6.2  Informative References

   [Krishnan] R. Krishnan et al. "draft-krishnan-sfc-long-lived-flow-
              use-cases", April 21, 2014
   [SFC PS]  P. Quinn et al. "draft-ietf-sfc-problem-statement-07", 
              June 24, 2014


Authors' Addresses


   Xinpeng Wei                        
   EMail: weixinpeng@huawei.com       






































X.Wei                   Expires January 1, 2015                 [Page 7]