One document matched: draft-hu-i2rs-overlay-use-case-04.txt
Differences from draft-hu-i2rs-overlay-use-case-03.txt
Network Working Group Fangwei. Hu
Internet-Draft ZTE
Intended status: Standards Track Bhumip. Khasnabish
Expires: January 29, 2015 ZTE USA Inc.
Chunming. Wu
Zhejiang University.
July 28, 2014
I2RS overlay use case
draft-hu-i2rs-overlay-use-case-04.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(ER) and Core Routers(CR). 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 focus on the encapsulation 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 January 29, 2015.
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document authors. All rights reserved.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Overlay Network Structure . . . . . . . . . . . . . . . . . . 3
2.1. Overview . . . . . . . . . . . . . . . . . . . . . . . . 3
2.2. The Benefit of Overlay Network Structure . . . . . . . . 5
2.3. Core Router Requirements . . . . . . . . . . . . . . . . 5
2.4. Edge Router Requirement . . . . . . . . . . . . . . . . . 5
3. MPLS Tunnel automatic configuration . . . . . . . . . . . . . 6
4. Security Alliance among ER . . . . . . . . . . . . . . . . . 7
5. Network Virtualization(NV) . . . . . . . . . . . . . . . . . 8
5.1. Benefits of Network Virtualization . . . . . . . . . . . 8
5.2. Applications and Requirements . . . . . . . . . . . . . . 9
5.3. Network Virtualization . . . . . . . . . . . . . . . . . 9
6. Security Considerations . . . . . . . . . . . . . . . . . . . 10
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
8. Normative References . . . . . . . . . . . . . . . . . . . . 10
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11
1. Introduction
The current Internet core hierarchical structure has remained largely
unchanged since its invention. In the face of growing traffic,
service providers must keep investing in bigger and faster routers
and links, especially in the core part of Internet, even though
revenues are growing quite slowly.
It is necessary to bring up a new structure to keep the core part
steadily and reduce the cost of core Router. In addition, as modern
networks grow in scale and complexity, the need for rapid and dynamic
control increases. I2RS ([I2RS-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
I2RS 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,
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We could reduce the cost of core forwarding device. This document
proposes an overlay network structure based on the I2RS framework.
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 MPLS data forwarding. The RIB table of the routers in
core part could only store very few IP routing record for management.
In this way, the expensive TCAM chip for routers in the core part
could be replaced by cheap ASIC chip, and the cost would be reduced
significantly. The full mesh tunnel is required for the edge
Routers. The forwarding routers in the overlay network are divided
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 would be MPLS switches
actually, and focus on fast MPLS data forwarding and receive only
policy related information(metadata)from the controller.
2. Overlay Network Structure
2.1. Overview
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+--------+ +--------+
| 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
Figure 1 Overlay Structure
The overlay structure is shown in Figure 1. The upper half part of
the Figure show 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. The Core Routers(MPLS Switches) are very simple and
focus on the MPLS data forwarding according to the label forwarding
table, and may not perceive any distinction among the tunnels to/from
Edge Routers.
The lower half of the Figure shows a logical tunnel network. All the
Edge Routers are connected via a logical-full mesh tunnel-based
connection among them. The tunnel could be MPLS tunnel. Edge Router
encapsulates/decapsulates MPLS data.
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2.2. The Benefit of Overlay Network Structure
(1) Lower cost down for Core Routers: For the Core Router, it is not
required to compute route, and distribute protocol 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 are very small. The size routing tables in the Core
Routers does not increase and remains stable with the growth of
the numbers of users.
(2) Improved network security: The overlay network structure
improves network security by splitting(and hence isolating)the
provider equipment and user station. The attacks from hacker to
core routers would therefore be separated by the edge routers.
(3) Support of 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 can be furnished by
special physical/virtual servers. The network virtualization
for Edge Router is discussed in section 3.
2.3. Core Router Requirements
The Core Router performs the following functions:
(1) Core Routers mainly focus on fast forwarding encapsulated data.
(2) The control plane is very simple. It announces and floods the
topology information.
(3) For compatibility reasons, Route computation may be needed, but
is not necessary.
2.4. Edge Router Requirement
The edge Router performs the following functions:
(1) Access and resources management: Edge Routers support user
Access authentication, authorization, and resource control and
management. When there is new user access network, the edge
router support user access authentication, authorization. If
the subscriber is legal and registered, he/she should should
pass the access authentication and authorization tests.
(2) Encapuslation data and tunnel type decision: Edge Router
negotiates with the peer Edge router based on the service
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traffic through controller, and encapsulates the original data
traffic.
(3) Topology management:Edge Router gathers the network topology
information and reports the topology to the controller. When
the topology changes, the edge router reports the changes as
well.
(4) Policy management: Edge Router identifies the policy from The
I2RS Commissioner([I2RS-FRM]).
(5) Service management: Edge Router should identifies the services
and performs the appropriate encapsulation.
(6) Route and signal protocol management: Edge Router computes route
based on the topology information received from other edge
router and core router.
(7) Tunnel control and management: Edge Routers manage and maintain
tunnel information. All the edge routers are connected over
logical full-mesh based tunnel network.
(8) Traffic analysis and reporting: Edge router monitors the data
traffic, and reports the traffic updates/changes.
3. MPLS Tunnel automatic configuration
The MPLS tunnel among the ER(edge Router) could be automatically
configured and established according to the client requirment
information. The procedure is as following: The controller (I2RS
clients) receives the VPN information from Edge Router through the
programmable interface of I2RS Agent. The VPN information includes
VPN Table ID, table item. The table item is composed of: item key
value, exit interface, VPN identifies, VPN forwarding identifies,
Master/Slave flag, load balance flag, keep alive time etc.
The item key value is the packet destination address. For example,
if the packet is encapsulated as L2VPN, the item key value is MAC
address, while if the packet is encapsulated as L3VPN,the item key
value is IP address.
Exit interface is the VPN binding interface or local device
identifies when it is as the VPN information send from I2RS Agent to
I2RS Client. If the VPN information is send from I2RS Client to SR/
CR through I2RS agent interface, the exit interface is the remote SR/
CR indentifies or the local tunnel ID, which indicates the end to end
connection from network management (I2RS Client) to CR/ER(I2RS
Agent).
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VPN identifies is used to identify the unique global VPN in the area.
VPN Table ID is the index of VPN user information item.
VPN forwarding identifies is used to identify the forwarding data
plane packet. Generally, it is the MPLS label.
Master/salve flag indicates the optimal and backup path, which could
be used as path protection or traffic engineering.
Load balance flag indicates multiple next hop for the forwarding
identifies, which is used for load balance.
Keep alive time indicates the alive time for the item
Network management collects all the VPN user information, and
computes the forwarding path and Unified policy based on it. Then it
download the forwarding information to each ER/SR through I2RS Agent
interface.
4. Security Alliance among ER
In the overlay network structure, the ER are full mesh. This session
provides a solution to setup SA(security Alliance) among ERs. The
security parameter negotiation could be finished through I2RS Client.
+--------------+
| |
. | Controller |.
/ | | \
. +--------------+ .
=============/=======================\==================
. ........... .
/ . . \
+------+ . Overlay . +------+
| +-------. .--------| |
| ER1 | . Tunnel . | ER2 |
+------+ ........... +------+
Take the following figure(figure 2) as example:
ER1 and ER2 need to establish SA(security Alliance), and adopt IPSec
as the security transport channel.
(1) ER1 and ER2 connect to controller(I2RS Client) by logical
tunnel, and the controller download the IPSec SA parameters to
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them respectively. The parameters include: VPN Type(for example
IPSec, L2VPN etc.), direction of AS(export or import), address
family(IPv4 or IPv6), encapsulation mode , encapsulation
protocol(AH or ESP), authentication algorithm (MD5 or SHA), ESP
algorithm mode(Encryption or compression algorithm), Encryption
mode, SA lifetime type, SA index, destination IP address of
IPSec, Source IP address of IPSec, Secret key, Security
parameter index information(SPI), Access control list(ACL)
configuration.
(2) ER1 and ER2 establish IPSec security channel respectively. They
negotiate the IPSec parameter with controller through IKE
protocol . By this way, the ERs and controller establish a
security and reliable connection link.
(3) The controller download the necessary parameters to ERs through
network routing protocol(such as BGP) or Netconf protocol.
(4) ERs receives the packets with required parameters from
controller(I2RS Client), and decryption the packets, then
writing the IPSec parameters to SD table.
(5) Then the Security alliance between ER1 and ER2 is established.
(6) When the Security alliance is expired, controller re-computes
the secret key, and restart the above steps to re-establish the
security alliance.
5. Network Virtualization(NV)
5.1. Benefits of Network Virtualization
(1) NV reduces ER complexity and equipment costs.
(2) NV allows flexibility and rapid deployment of new services;
services can also be quickly scaled up/down based on demands.
(3) Seamless support of scalability and reliability
(4) NV allows flexibility and simplicity of function combination,
for co-existence with hardware based network platform. An ER
could be utilized both as BRAS, Firewall, or NAT equipment on
the same hardware platform.
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5.2. Applications and Requirements
(1) Tunnel gateway elements: IPSec/SSL VPN gateway.
(2) Traffic analytics: DPI, QoS measurement, SLA agent.
(3) Converged and network-wide functions: AAA Server, policy control
and charging platform.
(4) Security function: Firewalls, virus scanners, instruction
detection and prevention systems.
5.3. Network Virtualization
Edge routers can support network virtualization, An ER can be a
hardware based platform, and the other necessary functions can be
supported via separate servers A programmable interface between
functional server and edge router can be used to support this
paradigm. When there is new service, we only need to add a new
server to support that service, and there may be minimal or no
changes required to the edge router.
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+--------------------+ +-------------------+
| +------+ +------+ | | +------+ +------+ |
| |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| |
| +--------+ +-------+ |
+------------------------------------------------+
Figure 2: Network Virtualization
6. Security Considerations
TBD
7. IANA Considerations
TBD
8. Normative References
[I2RS-FRM]
Atlas, A., Halpern, J., Hares, S., and D. Ward, "An
Architecture for the Interface to the Routing System",
draft-atlas-i2rs-architecture-00 (work in process), June
2013.
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Authors' Addresses
Fangwei Hu
ZTE
No.889 Bibo Rd
Shanghai 201203
China
Phone: +86 21 68896273
Email: hu.fangwei@zte.com.cn
Bhumip Khasnabish
ZTE USA Inc.
55 Madison Avenue, Suite 160
Morristown, New Jersey 07960
USA
Phone: +001-781-752-8003
Email: Bhumip.khasnabish@zteusa.com
Chunming Wu
Zhejiang University.
Hangzhou, Zhejiang
China
Email: wuchunming@zju.edu.cn
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