Internet DRAFT - draft-xu-homenet-twod-ip-routing

draft-xu-homenet-twod-ip-routing







Network Working Group                                              M. Xu
Internet-Draft                                                   S. Yang
Expires: February 23, 2014                                         J. Wu
                                                     Tsinghua University
                                                                 D. Wang
                                        Hong Kong Polytechnic University
                                                         August 22, 2013


          Two Dimensional-IP Routing Protocol in Home Networks
                  draft-xu-homenet-twod-ip-routing-01

Abstract

   Home network design faces many challenges currently.  Two of them are
   multi-homing and policy enforcement.  Different with other types of
   networks, home network operators are usually not professional
   technicians or geeks.  The problems we face are fundamentally related
   with the poor semantics provided by current destination-based routing
   protocol.

   TwoD-IP routing protocol is a link state routing protocol that makes
   routing decisions based on both destination and source addresses.
   This document describes the mechanism for supporting flexible multi-
   homing and policy routing across home networks.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
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   This Internet-Draft will expire on February 23, 2014.









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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   4
   3.  Scenario of Interests . . . . . . . . . . . . . . . . . . . .   4
     3.1.  Multi-homing in Home Networks . . . . . . . . . . . . . .   4
     3.2.  Access-control in Home Networks . . . . . . . . . . . . .   6
   4.  Protocol Overview . . . . . . . . . . . . . . . . . . . . . .   7
   5.  TwoD Link Metric Configuration  . . . . . . . . . . . . . . .   8
   6.  New Link State Advertisement/Database . . . . . . . . . . . .  10
   7.  Calculation of The Routing Table  . . . . . . . . . . . . . .  10
   8.  Forwarding Table Modification . . . . . . . . . . . . . . . .  10
   9.  Incremental Deployment  . . . . . . . . . . . . . . . . . . .  10
   10. Conclusion  . . . . . . . . . . . . . . . . . . . . . . . . .  10
   11. IANA Considerations . . . . . . . . . . . . . . . . . . . . .  10
   12. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  10
   13. References  . . . . . . . . . . . . . . . . . . . . . . . . .  11
     13.1.  Normative References . . . . . . . . . . . . . . . . . .  11
     13.2.  Informative References . . . . . . . . . . . . . . . . .  11
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  11




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1.  Introduction

   With more and more devices joining home networks, there are
   increasingly large residential home networks.  Traditionally, we keep
   home networks simple using single exit router (subnet) and default
   route.  However, more complex network technologies, such as multi-
   homing, appear when the networks become large.  Besides, users demand
   for more than connectivity service, as varieties of devices like
   private health sensors, exist in their home networks.  For example,
   users demand for finer granularity control for privacy and security
   reasons.  While we can not expect home network operators, who usually
   know nothing about network technologies, to configure complex network
   policies using tools like access control list (ACL).  We need a
   simpler and more flexible routing protocol in home networks.

   Traditionally, routing protocols make routing decisions solely based
   on destination IP addresses, so packets towards the same destination
   will be delivered to the same next hop no matter where they come
   from.  These protocols work well with simple home networks.  However,
   as users demand for more source-related functions and network
   techonologies evolve.  Destination-based routing protocol can not
   handle these demands, and even fail to provide the basic connectivity
   services.  For example, in the multi-homing scenario, packets may be
   dropped if forwarded only based on destination addresses [RFC3704].

   Although many patch-like solutions, like policy-based routing (PBR),
   can improve the situation.  However, they complex the configurations
   in home networks, and are not suitable for home network operators.
   The underlying cause for these problems is the lack of semantics of
   destination-based routing.  A new routing protocol that makes routing
   decisions based on both destination and source IP addresses is
   preferred in future home networks [I-D.ietf-homenet-arch].

   In this document, we propose a new link state routing protocol,
   called Two Dimensional-IP (TwoD-IP) routing protocol, that greatly
   enriches the routing semantics.  We list two important scenarios,
   including multi-homing and access control in home networks, where
   TwoD-IP routing protocol will apply.  We also use them as examples to
   illustrate the new routing protocol.

   We modify OSPF to support our TwoD-IP routing protocol.  With one
   more dimension, the routing protocol has to disseminate additional
   information with newly defined LSAs, and compute a two dimensional
   routing table based on the collected LSAs.  Thus, we must design new
   LSA packet formats, data structures and routing algorithms for the
   new routing protocol.





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2.  Terminology

   Terminology used in this document:

   o  TwoD-IP routing protocol: Two Dimensional IP routing protocol,
      which makes routing decisions based on both destination and source
      IP addresses.

   o  Guest Network: A subnet in a home network, that supports
      communication with other subnets in the home network and the
      Internet.

   o  Private Network: A subnet in a home network, that only supports
      communication with other subnets in the home network.

   o  Restricted Network: A subnet in a home network, that supports
      communication with other subnets in the home network and only
      parts of the Internet.

   o  TwoD Traffic Class: We borrow the definition from
      [I-D.baker-fun-routing-class], which describes it as a selector
      that identifies a set of traffic, e.g., from a stated source
      prefix and towards a stated destination prefix.

   o  TwoD Link Metric: The cost of travelling through a link, for a
      TwoD traffic class.

   o  TwoD-LSA: Link state advertisement that disseminates the TwoD link
      metric information across the network.

   o  TwoD-LSB: Extended link state database that stores the TwoD-LSAs.

3.  Scenario of Interests

   This section describes two scenarios, including multi-homing and
   policy routing, where TwoD-IP routing protocol will apply in home
   networks.  Note that TwoD-IP routing protocol can also apply in other
   scenarios, despite we focus on two important ones.

3.1.  Multi-homing in Home Networks

   In this scenario, a home network may be connected to multiple
   upstream ISPs.  The network is responsible for delivering packets to
   the exit router that is connected to the corresponding upstream ISP.

   For example, in Figure 1, a home network is connected with two ISPs,
   ISP1 and ISP2.  ISP1 has prefix P1 and is connected to the home
   network through border router BR1; ISP2 has prefix P2 and is



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   connected to the home network through border router BR2.  A host in
   the network is connected to the intermediate router I1, and obtains
   two addresses, A from P1 and B from P2.  Packets from the host
   towards the Internet should be sent to BR1 when the host uses address
   A, else the packets should be sent to BR2 when the host uses address
   B.

   The multi-homing scenario is an emerging requirement in home
   networks.  These networks are naturally connected to multiple
   upstream ISPs, e.g., broadband service provider and IPTV service
   provider, at the same time.  Packets could be dropped if they are not
   delivered to the right ISP.  For example, some IPTV service provider
   does not allow packets with any source addresses other than their own
   addresses.


                           +--------------------------+
                           |                          |
                           |       Internet           |
                           |                          |
                           |                          |
                           +--------------------------+
                           |                          |
               +-----------+---+                  +---+-------------+
               |               |                  |                 |
               |   ISP1: P1    |                  |    ISP2: P2     |
               |               |                  |                 |
               +--------+------+                  +-----+-----------+
                        |                               |
                     +--+---+                        +--+---+
                     |Router|                        |Router|
                     | BR1  |                        | BR2  |
                     +---+--+                        +---+--+
                   ------+------------+-  -+-------------+-----
                                    +-+----+-+
                                    | Router |
                                    |   I1   |
                                    +---+----+
                                 -------+--------
                                        |
                                     +--+---+  Address A in P1
                                     | Host |
                                     +------+  Address B in P2


             Figure 1: Multi-homing Scenario in Home Networks





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3.2.  Access-control in Home Networks

   Home networks will involve multiple subset and routers, as more and
   more dedicated devices including sensors are incorporated into home
   networks.  Different subsets in home networks usually have different
   privacy and security policies.  For instance, modern home routers
   will support both guest and private subnets [I-D.ietf-homenet-arch].

   For example, in Figure 2, a home network is divided into three
   subnets, the guest network, private network and restricted network.
   The guest network can communicate with all peer devices/hosts inside
   or outside the home network.  The private network can only
   communicate with all devices/hosts inside the home network.  For the
   restricted network, it can communicate with others inside the home
   network, but only has limited Internet access.

   Considering the importance of privacy and security in home network,
   this senario will be common in the home network enviroment.  With
   more and more devices, like some private health sensors taking part
   in, it is envisaged that home networks should provide a simple and
   flexible routing protocol, where access-control could be made in much
   finer granularity.


                               +---------------------+
                               |                     |
                               |       Internet      |
                               +----------+----------+
                              |
                                      +---+---+
                                      |       |
                               +------|  BR1  |------+
                               |      +-------+      |
        +------------+         |                     |         +------------+
        |            |     +---+---+             +---+---+     |            |
        |   Guest    |     |       |             |       |     |   Private  |
        |  Network   +-----+   I1  |             |   I2  +-----+   Network  |
        |            |     +---+---+             +---+---+     |            |
        +------------+         |                     |         +------------+
                               |      +-------+      |
                               +------|       +------+
                                      |   I3  |
                                      +---+---+
                                          |
                                    +-----+------+
                                    |            |
                                    | Restricted |
                                    |  Network   |



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                                    |            |
                                    +------------+


             Figure 2: Acess-control Scenario in Home Networks

4.  Protocol Overview

   TwoD-IP routing protocol is a link-state routing protocol, which is
   preferred in home network, as routing protocol can have knowledge of
   the whole home network topology [I-D.ietf-homenet-arch].  The new
   routing protocol can be self-configuring, and allows customizing for
   selected subnets.

   Similar with traditional OSPF protocol, TwoD-IP periodically gather
   link information and dynamically construct network topology.  Then
   routers within TwoD-IP routing protocol maintain link state data base
   that describes network topology.  After that, all routers will run
   routing algorithm that determines the next hop for each packet
   [RFC5340].

   Different with OSPF protocol, which makes routing decisions solely
   based on the destination IP address, and computes next hop towards
   different destination IP addresses; TwoD-IP routing protocol makes
   routing decisions based on both destination and source IP addresses.
   Thus, routers need to disseminate and store additional information,
   and run a different routing algorithm that computes next hop for
   different destination and source IP address pairs.

   In this document, we will focus on the differences between new TwoD-
   IP routing protocol and traditional OSPF protocol.  Basically, they
   can be divided into three parts: link metric configuration, link
   state advertisement/database, routing table calculation.

   With TwoD-IP routing protocol, all traffic can be classified into a
   TwoD traffic class, which can be represented by a (destination
   prefix, source prefix) pair.  Each packet falls into only one traffic
   class based on its destination and source IP addresses.  On each
   link, we can configure multiple two dimensional link metrics, each
   expresses the cost of a TwoD traffic class.  Such link metric is
   called TwoD link metric, and can be represented by a (destination
   prefix, source prefix, cost) triple.

   After link metric configuration, routers will disseminate these TwoD
   link metric with new LSA, which is call TwoD-LSA.  Receiving them,
   routers will store them into extended link state database (LSB),
   which can accommodate TwoD-LSAs.  The extended link state database is
   called TwoD-LSB.



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   With the TwoD-LSB, routers can run routing algorithm that computes
   the next hop for each TwoD traffic class.  Intrinsically, each TwoD
   traffic class will match a TwoD link metric on each link over the
   network.  Thus, each TwoD traffic class can obtain a full network
   topolgoy (which may be different with the topologies for other TwoD
   traffic classes).  Then the routing algorithm shall construct an SPT
   for the TwoD traffic class.  When a packet arrives, according to the
   TwoD traffic class that it falls into, it will flow along the
   corresponding SPT.  Note that a packet may fall into multiple TwoD
   traffic class, we resolve the confliction through the "Most Specific
   First" rule [I-D.baker-fun-routing-class].

5.  TwoD Link Metric Configuration

   Like OSPF, the TwoD link metric is configured in the interface data
   structure.  However, TwoD link metric is not solely a scalar that
   describes the cost of sending a packet on the interface, but a triple
   (destination prefix, source prefix, cost) that describes the cost of
   sending a packet for TwoD traffic class (destination prefix, source
   prefix).  A single link can be configured to have multiple TwoD link
   metrics, each for a different TwoD traffic class.  Note that the
   links can be automatically configured to have (*,*,1), that
   degenerates into the default configuration for traditional OSPF.


               +---------------+                  +-----------------+
               |               |                  |                 |
               |   ISP1: P1    |                  |    ISP2: P2     |
               |               |                  |                 |
               +--------+------+                  +-----+-----------+
                        |IF1:(*,P1,1)                   |IF2:(*,P2,1)
                     +--+---+(*,P2,1000)             +--+---+(*,P1,1000)
                     |Router|                        |Router|
                     | BR1  |                        | BR2  |
                     +---+--+                        +---+--+
                   ------+------------+-  -+-------------+-----
                                    +-+----+-+
                                    | Router |
                                    |   I1   |
                                    +---+----+
                                 -------+--------
                                        |
                                     +--+---+  Address A in P1
                                     | Host |
                                     +------+  Address B in P2


   Figure 3: TwoD link metric configuration in the multi-homing Scenario



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   Continuing the example in Figure 1, we plot the TwoD link metric
   configuration in Figure 3.  We only have to configure the out-going
   interface (like IF1 and IF2) on the border routers.  On IF1, we
   configure two TwoD link metrics, (*, P1, 1) and (*, P2, 1000),
   indicating packets from P1 will traverse the link with cost 1 while
   packets from P2 will traverse the link with much higher cost, 1000.
   Similarly, on IF2, we also configure two TwoD link metrics, (*, P2,
   1) and (*, P1, 1000).  With this configuration, traffic from P1 (or
   P2) will see a topology where the path through ISP1 (or ISP2) costs
   much less than the path through ISP2 (or ISP1).  Packets from P1 (or
   P2) will never be diverted to ISP2 (or ISP1) unless the connection
   with ISP1 (or ISP2) fails.

   Also continuing the example in Figure 2, we plot the TwoD link metric
   configuration in Figure 4.  Let PX, PY, and PZ be the prefix of the
   guest, private and restricted network, PR be the private prefix used
   in the home network, and PV be the prefix in the Internet which the
   restricted network can communicate with.  We only have to configure
   the router interfaces (like IFA, IFB and IFC) where the subnets are
   connected.  On IFA, we only have to configure (PX, *, 1) as all
   traffic can travel into the guest network.  We have to configure (PY,
   PR, 1) on IFB, because only hosts from the home network (using
   address in the private prefix) can travel into the private network.
   At last, we have to configure (PZ, PR, 1), (PZ, PV, 1) on IFC,
   because not only hosts inside the home network, but also hosts from
   PV, can access the restricted network.



                                      +---+---+
                                      |       |
                               +------|  BR1  |------+
                               |      +-------+      |
        +------------+ (PX,*,1)|                     |(PY,PR,1)+------------+
        |            |     +---+---+             +---+---+     |            |
        |   Guest    |  IFA|       |             |       |IFB  |   Private  |
        |  Network   +-----+   I1  |             |   I2  +-----+   Network  |
        |            |     +---+---+             +---+---+     |    :PX     |
        +------------+         |                     |         +------------+
                               |      +-------+      |
                               +------|       +------+
                                      |   I3  |
                                      +---+---+ (PZ,PV,1)
                                          |IFC  (PZ,PR,1)
                                    +-----+------+
                                    |            |
                                    | Restricted |
                                    |  Network   |



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                                    |   :PY      |
                                    +------------+


       Figure 4: TwoD link metric configuration in the acess-control
                                 Scenario

6.  New Link State Advertisement/Database

   TBD.

7.  Calculation of The Routing Table

   TBD.

8.  Forwarding Table Modification

   Traditional forwarding table only supports making forwarding
   decisions based on destination IP addresses.  TwoD-IP routing
   protocol needs a new forwarding table structure that supports making
   forwarding decisions based on both destination and source IP
   addresses.  This can be achieved through a variety of ways, we will
   discuss them in the next version of this document.

9.  Incremental Deployment

   TwoD-IP routing protocol should support incremental deployment, i.e.,
   deploying one or two routers shall be useful in certain scenarios.
   However, with more routers deployed, the network should be more
   flexible to support policies with finer granularity.

10.  Conclusion

11.  IANA Considerations

   Some newly designed TwoD-IP routing protocols may need new protocol
   numbers assigned by IANA.

12.  Acknowledgments

   Zheng Liu and Gautier Bayzelon provided useful input into this
   document.









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13.  References

13.1.  Normative References

   [RFC3704]  Baker, F. and P. Savola, "Ingress Filtering for Multihomed
              Networks", BCP 84, RFC 3704, March 2004.

   [RFC5340]  Coltun, R., Ferguson, D., Moy, J., and A. Lindem, "OSPF
              for IPv6", RFC 5340, July 2008.

13.2.  Informative References

   [I-D.ietf-homenet-arch]
              Chown, T., Arkko, J., Brandt, A., Troan, O., and J. Weil,
              "Home Networking Architecture for IPv6", draft-ietf-
              homenet-arch-07 (work in progress), February 2013.

   [I-D.baker-fun-routing-class]
              Baker, F., "Routing a Traffic Class", draft-baker-fun-
              routing-class-00 (work in progress), July 2011.

Authors' Addresses

   Mingwei Xu
   Tsinghua University
   Department of Computer Science, Tsinghua University
   Beijing  100084
   P.R. China

   Phone: +86-10-6278-5822
   Email: xmw@csnet1.cs.tsinghua.edu.cn


   Shu Yang
   Tsinghua University
   Department of Computer Science, Tsinghua University
   Beijing  100084
   P.R. China

   Phone: +86-10-6278-5822
   Email: yangshu@csnet1.cs.tsinghua.edu.cn










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   Jianping Wu
   Tsinghua University
   Department of Computer Science, Tsinghua University
   Beijing  100084
   P.R. China

   Phone: +86-10-6278-5983
   Email: jianping@cernet.edu.cn


   Dan Wang
   Hong Kong Polytechnic University
   Department of Computing, Hong Kong Polytechnic University
   Hong Kong
   P.R. China

   Phone: +852-2766-7267
   Email: csdwang@comp.polyu.edu.hk

































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