Internet DRAFT - draft-xu-homenet-twod-ip-routing
draft-xu-homenet-twod-ip-routing
Network Working Group M. Xu
Internet-Draft J. Wu
Intended status: Standards Track Tsinghua University
Expires: 25 September 2022 S. Yang
L. Cui
Shenzhen University
D. Wang
Hong Kong Polytechnic University
24 March 2022
Two Dimensional-IP Routing Protocol in Home Networks
draft-xu-homenet-twod-ip-routing-02
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
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This Internet-Draft will expire on 25 September 2022.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Scenario of Interests . . . . . . . . . . . . . . . . . . . . 4
3.1. Multi-homing in Home Networks . . . . . . . . . . . . . . 4
3.2. Access-control in Home Networks . . . . . . . . . . . . . 5
4. Protocol Overview . . . . . . . . . . . . . . . . . . . . . . 6
5. TwoD Link Metric Configuration . . . . . . . . . . . . . . . 8
6. New Link State Advertisement/Database . . . . . . . . . . . . 10
7. Calculation of The Routing Table . . . . . . . . . . . . . . 11
8. Forwarding Table Modification . . . . . . . . . . . . . . . . 11
9. Implementation . . . . . . . . . . . . . . . . . . . . . . . 11
10. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . 11
11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11
12. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 11
13. References . . . . . . . . . . . . . . . . . . . . . . . . . 11
13.1. Normative References . . . . . . . . . . . . . . . . . . 11
13.2. Informative References . . . . . . . . . . . . . . . . . 12
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12
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
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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 [1].
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 [3].
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.
2. Terminology
Terminology used in this document:
* TwoD-IP routing protocol: Two Dimensional IP routing protocol,
which makes routing decisions based on both destination and source
IP addresses.
* Guest Network: A subnet in a home network, that supports
communication with other subnets in the home network and the
Internet.
* Private Network: A subnet in a home network, that only supports
communication with other subnets in the home network.
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* Restricted Network: A subnet in a home network, that supports
communication with other subnets in the home network and only
parts of the Internet.
* TwoD Traffic Class: We borrow the definition from [5], 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.
* TwoD Link Metric: The cost of travelling through a link, for a
TwoD traffic class.
* TwoD-LSA: Link state advertisement that disseminates the TwoD link
metric information across the network.
* 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
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.
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+--------------------------+
| |
| Internet |
| |
| |
+--------------------------+
| |
+-----------+---+ +---+-------------+
| | | |
| ISP1: P1 | | ISP2: P2 |
| | | |
+--------+------+ +-----+-----------+
| |
+--+---+ +--+---+
|Router| |Router|
| BR1 | | BR2 |
+---+--+ +---+--+
------+------------+- -+-------------+-----
+-+----+-+
| Router |
| I1 |
+---+----+
-------+--------
|
+--+---+ Address A in P1
| Host |
+------+ Address B in P2
Figure 1: Figure 1: Multi-homing Scenario in Home Networks
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 [3].
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.
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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 |
| |
+------------+
Figure 2: 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 [3]. The new routing protocol can be
self-configuring, and allows customizing for selected subnets.
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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 [2].
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.
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 [5].
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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: 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.
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+---+---+
| |
+------| 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 |
| :PY |
+------------+
Figure 4: Figure 4: TwoD link metric configuration in the acess-
control Scenario
6. New Link State Advertisement/Database
The new protocol need to carry source address prefixes information in
link state advertisements. We use the OSPF extension in [4] to carry
the additional prefixes. The format of the extended TLV is defined
as following.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| PrefixLength | PrefixOptions | 0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Address Prefix |
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 5: extension tlv
* Type: Assigned by IANA as denoted in Section 8.1 of [4].
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* Length: Length of an IPv6 prefix plus 4 bytes, which is equal to
20.
* PrefixLength, PrefixOptions, and Address Prefix: Denoting an IPv6
prefix, as defined in [2].
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. Implementation
We have developed a prototype of the TwoD-IP policy routing protocol
based on Quagga, and set up tests with a small scale testbed.
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.
13. References
13.1. Normative References
[1] Baker, F. and P. Savola, "Ingress Filtering for Multihomed
Networks", BCP 84, RFC 3704, DOI 10.17487/RFC3704, March
2004, <https://www.rfc-editor.org/info/rfc3704>.
[2] Coltun, R., Ferguson, D., Moy, J., and A. Lindem, "OSPF
for IPv6", RFC 5340, DOI 10.17487/RFC5340, July 2008,
<https://www.rfc-editor.org/info/rfc5340>.
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[3] Chown, T., Ed., Arkko, J., Brandt, A., Troan, O., and J.
Weil, "IPv6 Home Networking Architecture Principles",
RFC 7368, DOI 10.17487/RFC7368, October 2014,
<https://www.rfc-editor.org/info/rfc7368>.
[4] Lindem, A., Roy, A., Goethals, D., Reddy Vallem, V., and
F. Baker, "OSPFv3 Link State Advertisement (LSA)
Extensibility", RFC 8362, DOI 10.17487/RFC8362, April
2018, <https://www.rfc-editor.org/info/rfc8362>.
13.2. Informative References
[5] Baker, F., "Routing a Traffic Class", Work in Progress,
Internet-Draft, draft-baker-fun-routing-class-00, 1 July
2011, <http://www.ietf.org/internet-drafts/draft-baker-
fun-routing-class-00.txt>.
Authors' Addresses
Mingwei Xu
Tsinghua University
Department of Computer Science, Tsinghua University
Beijing
100084
P.R. China
Phone: +86-10-6278-5822
Email: xmw@cernet.edu.cn
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
Shu Yang
Shenzhen University
South Campus, Shenzhen University
Shenzhen
518060
P.R. China
Phone: +86-755-2653-4078
Email: yang.shu@szu.edu.cn
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Laizhong Cui
Shenzhen University
South Campus, Shenzhen University
Shenzhen
518060
P.R. China
Phone: +86-755-8695-6280
Email: cuilz@szu.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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