Hi, All
A new version of I-D about overlay use case is attached.
Comments are appreciately welcomed.
Network Working Group Fangwei. Hu
Internet-Draft Bhumip. Khasnabish
Intended status: Standards Track ZTE
Expires: August 5, 2013 Feb 2013
I2RS overlay use case
draft-hu-i2rs-overlay-use-case-00.txt
Abstract
This document proposes an overlay network use case. The forwarding
routers network is an overlay structure. There are two kinds of
forwarding routers: Edge Router and Core Routers. Edge Router
encapsulates format data based on the tunnel type, which are
established among Edge Routers. Core Router would be very simple and
cheap. It foucs on the encapuslation data forwarding. In order to
reduce the equipment cost of Edge Routers, the network virtualization
is provided in this document.
Network Working Group Fangwei. Hu
Internet-Draft Bhumip. Khasnabish
Intended status: Standards Track ZTE
Expires: August 5, 2013 Feb 2013
I2RS overlay use case
draft-hu-i2rs-overlay-use-case-00.txt
Abstract
This document proposes an overlay network use case. The forwarding
routers network is an overlay structure. There are two kinds of
forwarding routers: Edge Router and Core Routers. Edge Router
encapsulates format data based on the tunnel type, which are
established among Edge Routers. Core Router would be very simple and
cheap. It foucs on the encapuslation data forwarding. In order to
reduce the equipment cost of Edge Routers, the network virtualization
is provided in this document.
Status of this Memo
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This Internet-Draft will expire on August 5, 2013.
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document authors. All rights reserved.
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include Simplified BSD License text as described in Section 4.e of
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described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Overlay Network Structure . . . . . . . . . . . . . . . . . . . 3
2.1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.2. The Benefit of Overlay Network Structure . . . . . . . . . 5
2.3. Core Router Requirement . . . . . . . . . . . . . . . . . . 5
2.4. Edge Router Requirement . . . . . . . . . . . . . . . . . . 5
3. Network Virtualization . . . . . . . . . . . . . . . . . . . . 6
3.1. Benefit of Network Virtualization . . . . . . . . . . . . . 6
3.2. Application and Requirement . . . . . . . . . . . . . . . . 6
3.3. Network Virtualization . . . . . . . . . . . . . . . . . . 7
4. Security Considerations . . . . . . . . . . . . . . . . . . . . 7
5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 8
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 8
7. Normative References . . . . . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 8
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1. Introduction
As modern networks grow in scale and complexity, the need for rapid
and dynamic control increases. I2RS([IRS-FRM]) provide a new routing
system framework to meet the requirement. There is a programmable
interface for the forwarding router. All the forwarding routers
should support IRS agent to communicate with controllers. The
forwarding routers gather the traffic and topology information,
report to the controllers, and receive the policy from controllers.
Besides the idea of programmable and open interface, another key
feature is forwarding plane and control plane separation in the I2RS
and software define network. Some of the control and computing
function could be separation from traditional routers. By this way,
we hope that the service and data encapsulation are all done in the
routers of the edge of network, and the routers in the core part are
only focus on data forwarding. The core routers RIB table could only
store the network(or equipment) IP prefix, and does not store user(or
end station) IP prefix anymore. The RIB and FIB table capability of
core routers would be greatly lower, and the equipment cost could be
down. The full mesh tunnel is required for the edge Routers. This
is actually an overlay network structure. The forwarding routers in
the overlay network are divides into two kinds based on the roles in
the network: CR(Core Router) and ER(Edge Router).The Edge Routers
encapsulate the forwarding data based on the tunnel type, gather
topology information, and report traffic to the controller, while
Core Routers focus on fast data forwarding and receive policy from
controller.
2. Overlay Network Structure
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2.1. Overview
+--------+ +--------+
| Edge +--+ +---| Edge |
| Router | | | | Router |
+--------+ | | +--------+
| +------+ +------+ |
| | Core | |Core | |
+--|Router|---------- |Router|-+
+------+ +------+
/ \
/ \
+--------+ / physical topology \ +--------+
| Edge |--+ +----| Edge |
| Router | | Router |
+--------+ +--------+
===================================================================
+--------+ +--------+
| Edge |--+ +----| Edge |
| Router | | | | Router |
+--------+ | ................... | +--------+
| . . |
| . * * . |
+----. * * .-----+
/. * * .
/ . * * .
/ .Overlay * Tunnel .
+--------+ / . * * .-----+ +--------+
| Edge +--+ . * * . | | Edge |
| Router | . * * . +----| Router |
+--------+ ...*............*.. +--------+
Logical Tunnel
The overlay structure is as the above figure. The above part of the
figure is a physical network. The Edge Routers are located in the
edge of the overlay network, and are logically connected through Core
Routers.The services and data encapsulation are done in the edge
routers. Core Router should be very simple and cheap, which focus on
the data forwarding, and does not perceive the tunnel among Edge
Routers.
The below part is a logical tunnel network. All the Edge Routers are
logcail full mesh connection through the tunnel among them. The
tunnel could be IP/MPLS/OTN tunnel. Edge Router encapsulates/
decapsulates the data based on the tunnel type. If tunnel type is IP
network, the encapsulation format would be IP over GRE, or IP over
UDP. If tunnel is MPLS network, the encapsulation format is IP over
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MPLS, is similar with MPLS data format. If tunnel is OTN, the tunnel
format is IP/ethernet over ODU.
2.2. The Benefit of Overlay Network Structure
(1) Cost down for Core Router: For the Core Router, there is not
necessary to compute route, and distribute protocl signal. The
Core Routers only store the equipment IP prefix, and do not
store user IP prefix any more. The RIB and FIB table for core
Router is very small. The routing table in the Core Routers are
not increased and keep stable with the growing of users.
(2) Improving the network security: The overlay network structure
improves the network security by split the provider equipment
and user station. The attacks from hacker to core routers would
be separated by the edge routers.
(3) Network virtualization: Some of the control and computing
function could be separated from Edge Router and be done by
controller. The edge router in the future is a hardware
platform. The service, policy ,and other control function, such
as route computing, signal distribution are finished by special
servers. The network virtualization for Edge Router is
discussed in section 3.
2.3. Core Router Requirement
The Core Router is required:
(1) Core Router mainly focus on fast forwarding encapsulation data.
(2) The control plane is very simple. It announces and floods the
topology information.
(3) For compatible, Route computing is needed, but is not necessary.
2.4. Edge Router Requirement
The edge Router is required as following:
(1) Edge Router should support user Access authentication,
authorization, and resource controller. When there is new user
access network, the edge router support user access
authentication, authorization. If the user is legal, it should
pass the access authentication and authorization.
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(2) Topology management. Edge Router should gather the network
topology and report the topology to controller. When the
topology changes, the edge router reports the changes.
(3) Policy management. Edge Router should identify the policy from
commissioner([IRS-Policy]).
(4) Service management: Edge Router should identify the services and
do the correct encapsulation.
(5) Route and signal protocol: Edge Router could compute route based
on the topology information received from other edge router and
core router.
(6) Tunnel management control: Edge Routers manage and maintain
tunnel information. All the edge routers should be logical
full-mesh based on the tunnel.
(7) Traffic analysis and report: Edge router monitors the data
traffic, and reports the traffic changes.
3. Network Virtualization
3.1. Benefit of Network Virtualization
(1) Reduce ER complex and equipment costs.
(2) Flexible and fast new services deployment: services can be
rapidly scaled up/down as required.
(3) Increase scalability and reliability.
(4) Easy for function combination, achieving co-existence with
hardware based network platform. ER could be act both as BRAS,
or Firewall, or NAT equipment on the same hardware platform.
3.2. Application and Requirement
(1) Tunnel gateway elements: IPSec/SSL VPN gateway.
(2) Traffic analytics: DPI, QoS measurement, SLA agent.
(3) Converged and network-wide function: AAA Server, policy control
and charging platform.
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(4) Security function: Firewalls, virus scanners, instruction
detection and prevention systems.
3.3. Network Virtualization
Edge router supports network virtualization, it is a hardware based
platform, the function model is separation from the edge router.
There is a programmable interface between function server and edge
router. When there is new service, we only add some new servers to
support the service, and there is no or little changes to the edge
router.
+--------------------+ +-------------------+
| +------+ +------+ | | +------+ +------+ |
| |DPI | |NAT | | | |DPI | |NAT | |
| |Server| |Server| | | |Server| |Server| |
| +------+ +------+ | | +------+ +------+ |
| +------+ | | +------+ |
| | QOS | | | | QOS | |
| |Server| | | |Server| |
| +------+ | | +------+ |
+-----+--------------+ virtualization +---------------+---+
======|=======================================================|====
. .
| +------------------------------------------------+ .
. | +--------+ +-------+ | |
|- +-->| Edge | | Edge |<--+---.
. | | Router | | Router| | |
| | +--------+ +-------+ | .
. | Overlay Network | |
| | +-------+ +-------+ | .
. | | Core |-----| Core | | |
| | | Router| | Router| | .
. | +-------+ +-------+ | |
| | | .
. | +--------+ +-------+ | |
+--+->| Edge + | Edge |<--+---+
| | Router | | Router| |
| +--------+ +-------+ |
+------------------------------------------------+
4. Security Considerations
TBD
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5. Acknowledgements
TBD
6. IANA Considerations
TBD
7. Normative References
[IRS-FRM] Atlas, A., Nadeau, T., and D. Ward, "Interface to the
Routing System Framework",
draft-ward-irs-framework-00 (work in process), July 2012.
[IRS-Policy]
Atlas, A., Hares, S., and J. Halpern, "A Policy Framework
for the Interface to the Routing System",
draft-atlas-irs-policy-framework-00 (work in process),
September 2012.
Authors' Addresses
Fangwei Hu
ZTE
No.889 Bibo Rd
Shanghai, 201203
China
Phone: +86 21 68896273
Email: [email protected]
Bhumip Khasnabish
ZTE
USA
Email: [email protected]
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