Allied Telesis IPv6 User Manual 2

Solutions Guide

High Availability IPv6

Introduction

The Internet has forever changed

contemporary society, with online
access an integral part of our 21st
century lifestyles. Finding out what
movie is on, or the location of a
restaurant when out with your smart­phone, shopping online and booking
your next holiday are just a few of
the things we now take for granted.
Businesses rely on online resources
more than ever, with everything from
standard access to email and servers,
to business critical applications such as
medical systems, transpor t signalling,
and security requiring a high availability
network.

The Internet and networks in general

rely on Internet Protocol (IPv4)
addresses for connectivity and to
manage communication between
separate systems as well as individual
devices. The extraordinary growth of
connected systems and devices has
necessitated a move towards using
the next generation IP communication
protocol, known as IPv6.

Allied Telesis networks provide small,

medium and large organizations
with a cost-effective solution for
resilient, wirespeed IPv4 and IPv6
communication.

Allied Telesis offers high-availability

solutions across a range of Layer 3
switch products, with a wide choice of
Ethernet port combinations and price/
performance options. We are able
to offer solutions to everyone from
small schools to urban rail systems
to businesses with thousands of
employees.

In our key medical and transport
sectors, network-based applications
may be sensitive to even a few
seconds of communication failure.

We understand that a high availability

infrastructure is no longer a luxury;
maintaining resource availability and
data security is now of paramount
importance.

This solution explores the key Allied
Telesis technologies that ensure a

smooth transition to IPv6 networking
to provide a high availability
infrastructure, including the dynamic
routing of data.

Benefits

The principal benefits of the high
availability IPv6 solution are:

» Resiliency

» Ease of management

» Ease of transition from IPv4

» Scalability

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Next generation network transition

Allied Telesis solutions offer the same
levels of performance, high availability
and manageability for both IPv4 and IPv6
networks. As you move from a current
IPv4 network to a next generation
IPv6 network, some transition will be
required to ensure the new network
will communicate with other local and
remote devices and systems. Allied
Telesis provide two mechanisms to
facilitate this transition; dual stack and
tunnelling.

With dual stacking, IPv4 and IPv6
can co-exist seamlessly on the same
equipment, using equivalent routing
protocols, within the same topology.
An organization can be condent that
the network will support their transition
from IPv4 to IPv6 at a pace that suits
them. Their IPv6 network can be
overlaid on the same equipment, in the
same physical and logical layout, as their
original IPv4 network.

The equipment can be managed equally
by IPv4 or IPv6, enabling a smooth
transition of the network management
infrastructure as well.

Tunnelling allows IPv6 trafc to be
encapsulated within IPv4 packets. This
means an organization wishing to move
to IPv6 can do so even if their Internet
and other remote connectivity still
require IPv4.

As modern networks have grown in
both size and functionality, dynamic
routing protocols have been employed
to manage trafc paths and load across
the various devices and components
of the network. Newer versions of
these dynamic routing protocols have
been created to support the increasing
prevalence of IPv6. For example OSPFv3
is an update on OSPFv2 to support IPv6
networks.

Allied Telesis IP transition technologies,
and support for the latest versions
of commonly used dynamic routing
protocols, ensure an easy transition to
next generation networking, without
having to change infrastructure or
update key networking components.

In particular, the area layout and subnet
allocation used for IPv4 with OSPFv2
can be overlaid with an equivalent
structure for IPv6 with OSPFv3.
Thereby, the logical network structure
that has been established for an existing
IPv4 network can seamlessly carry over
to the coexisting IPv6 network as
shown in diagram 1 on page 4.

Allied Telesis creates off-the-shelf
switches and routers with feature­rich, high-performance IPv4 and
IPv6 implementations in the same
box.

High Availability IPv6 | 3

Current IPv4 network

Area 0

Transition to IPv6

IPv4

IPv6

x900

IPv4

IPv6

OSPFv2

OSPFv3

x900

Area 0

x900

IPv4

OSPFv2

x610

x900

x610

OSPFv2

IPv4

Area 1

OSPF

x610

Area 1

Diagram 1

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IPv6
IPv6

IPv4

x610

x610

IPv4

IPv6

OSPFv2

OSPFv3

Area 1

OSPF

x610

Area 1

High availability IPv6 networking

Allied Telesis high availability solutions
work equally well for IPv4 and IPv6
networks, and even networks that are
in transition using a combination of both
protocols. To provide a highly resilient
solution requires that the infrastructure
and features of the networking
equipment, as well as the trafc passing
through the devices, is well managed
and can survive any disturbance or
interruption to normal network
connectivity.

With most networks making use
of routing protocols, it is imperative
that the dynamic nature of this trafc
management is handled in any fault
situation to ensure continuous online
resource access is not compromized.
Adding dynamic routing resilience
to high availability network design
guarantees superior performance.

VCStack provides a network
infrastructure with no single point of
failure that automatically responds to
any connectivity loss. Graceful restart
manages changes in the network
topology to keep active paths through
the network available, and minimize
downtime that might otherwise be
experienced when a network switch is
taken ofine.

We can take a closer look at these two
technologies.

Allied Telesis provides a completely
resilient solution for next generation
networks – minimize downtime
and maximize access to online
resources and applications.

Virtual Chassis Stacking

(VCStack)

Using VCStack at the core of your
network allows multiple switches to
appear as a single virtual chassis. This
virtual chassis acts as a single switch,
simplifying management.

With VCStack, Allied Telesis now
provides a truly resilient network. In
normal operation, all bandwidth and all
routing power in the network are fully
available for use all the time. If a link or
device fails, some of the bandwidth or
forwarding power will be lost, but the
network will still be fully operational and
all remaining resources will continue to
be fully utilized.

Two key technologies from which we
have built the high-availability IPv6
solution are Virtual Chassis Stacking
(VCStack™) and graceful restart (also
known as non-stop forwarding).

High Availability IPv6 | 5

Diagram 2 shows link aggregation between the core VCStack

Link aggregation

10 Gigabit link

1 Gigabit link

10/100 link

SBx908

Server Farm

CORE

EDGE

Remote

VPN

Router

x610

8100S

8100S

Internet

Network
Attached

Storage

Router

and edge switches. With link aggregation across ports on
different virtual chassis members, there is no perceptible
disruption in the case of a link failure, and the full bandwidth of
the network is available. Link aggregation is also used to connect
network resources, such as servers, across the virtual chassis
members. This ensures device and path resiliency.

Fast failover between stack members provides for an almost
uninterrupted network service. In a VCStack environment, one
of the stack members acts as the master switch, and provides
decision making for the virtual chassis. All of the other VCStack
members are in active standby, also having learnt routing and
forwarding information for the network to ensure that if the
master were to fail, another member is able to seamlessly
assume control of the virtual chassis with minimal network
downtime. Failover and recovery can be completed in as little as
three seconds.

Allied Telesis also includes long distance stacking in the VCStack
solution. Long distance stacking enables the VCStack solution
to provide a distributed network core. The increased distance
provided by ber stacking connectivity means that members
of the virtual chassis do not have to be co-located, but can be
kilometres apart.

All of the benets and powerful features of VCStack remain
exactly the same – Allied Telesis long distance stacking provides
a genuine distributed virtual network core.

The powerful VCStack solution offers uninterrupted network
access and high availability of critical resources, and yet is very
simple to manage with almost plug-and-play conguration.
Whether your virtual chassis is located in the same equipment
rack, or distributed across the campus, VCStack provides
resiliency, scalability and ease of management.

Diagram 2

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Graceful restart for dynamic routing protocols

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6

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v

4

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Along with VCStack, the other key component of this IPv6 high
availability solution is the implementation of graceful restart
(also known as non-stop forwarding) within IPv6 dynamic
routing protocols. Graceful restart is a feature that has been
added to routing protocols (RIP, OSPF, BGP) in recent years. It
enables Layer 3 routing to continue uninterrupted even while
one of the routers in the network is, for a brief period, not
participating in the routing protocol that is used to populate the
routers’ route tables.

In normal circumstances, when routers detect that a neighbor
is no longer participating in the routing protocol, they discard
routes learnt from that neighbor. With graceful restart, the
router that is going to briey drop out of the protocol can
inform its neighbors of its intention, and request that they
continue to operate as though it was still participating.

Combining VCStack and graceful restart allows achievement of
true Layer 3 router resiliency. VCStack enables multiple Layer 3
switches to operate together as one, and graceful restart keeps
data owing if the master switch of the VCStack is lost and the
stack briey drops out of a routing protocol while a new master
takes over.

Combining that with graceful restart within the routing
protocols provides a solution that can enable a Layer 3 switched
IPv6 network to hitlessly recover from link loss, and recover
from the loss of a stack member in very few seconds.

Summary

The standard Internet protocol of the future is IPv6. In the
coming years, a great deal of time and effort will be expended
in the process of transferring data communication systems
from IPv4 to IPv6. The simpler this process is made for
people, the more smoothly it will progress, and the less it will
cost.

By providing a resilient Layer 3 switching solution, at an
affordable price, that enables IPv4 and IPv6 to work in parallel
with equal reliability and performance, Allied Telesis is able to
help smooth the transition, as shown in diagram 3.

Full support for IPv6 transition technologies and resilient
network products and protocols ensure that Allied Telesis
switching technology provides a solution that is easy to
manage, scalable and future-proof.

Diagram 3 - IPv4 and
IPv6 dynamic routing in

Internet

Servers

x600

x600

x600

ACCESS

High Availability IPv6 | 7

SBx908

parallel via a VCStack
Layer 3 switch

Products

Allied Telesis has a range of products that will make the transition

SwitchBlade x908

ADVANCED LAYER 3 MODULAR SWITCHES

The Allied Telesis SwitchBlade® x908
advanced Layer 3 modular switch offers
high exibility and density in a small
physical size, providing scalable and
versatile switching solutions for today’s
enterprise networks. Each chassis
supports eight high-speed 60Gbps
expansion bays, and can be paired in a
VCStack.

■



10GbE/GbE aggregator for mid-size
data center or network core

■ 3RU medium density modular

platform

■ 8 x 60Gbps ‘XEM’ module bays

(same XEMs as x900 family)

■ Hot-swappable PSUs, 1 + 1 PSU

redundancy

Max capability:

■ 96 x GbE ports

■ 16 x 10GbE ports

With VCStack passive backplane:

■ 192 x GbE ports

■ 32 x 10GbE ports

Key features

» Resilient

» Scalable

» Reliable

» High-performing

» Easy to manage

x610 Series

ADVANCED LAYER 3+ GIGABIT ETHERNET

STACKABLE SWITCHES

The Allied Telesis x610 Series is the high performing and
scalable solution for today’s networks, providing an extensive
range of por t-density and uplink-connectivity options. With
a choice of 24/48-port versions with optional 10 Gigabit
uplinks and PoE+ ports, plus the ability to stack up to eight
units, the x610 Series can connect anything from a small
workgroup right up to a large business.

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x900 Series

ADVANCED LAYER 3 SWITCHES

The Allied Telesis x900 Series is one of our most advanced series of
switches and is unmatched in performance, exibility and reliability. This
series provides ne service provisioning granularity, high availability, and
advanced QoS. All x900 switches incorporate a switching core that
yields wirespeed IPv4 and IPv6 routing and most switches feature robust
hardware with dual hot-swappable power supplies.

■ 1RU semi modular platform

■ Hot-swappable PSUs

■ 1 + 1 PSU redundancy

Typical conguration:
24 or 36 x 10/100/1000T ports

AT-XEM-2XP

2 x 10GbE (XFP) ports
AT-XEM-2XS
2 x 10GbE (SFP+) ports

AT-XEM-2XT

2 x 10GbE (RJ-45) ports

AT-XEM-12S

12 x 100/1000X SFP ports

AT-XEM-12T

12 x 10/100/1000T (RJ-45) ports

AT-XEM-STK

2 x high-speed stacking ports

■ Allied Telesis x900 Series switches

encompass the advanced features
required in modern converged data
center environments.

■ The x900 Layer 3+ switches have

fully non-blocking switching on all
ports, so IPv4 Layer 2 switching and
Layer 3 routing occur at wirespeed.
This is ideal for high-end server
deployments, and when aggregating
Gigabit connections.

■ The x900 switches also feature

front-to-back cooling, maximizing
their reliability in respect of the
cooling requirement of the data
center.

■ 10GbE expansion modules provide

high-speed uplinks, with the option
of up to 40Gbps capacity to the
network core.

■ The x900 Layer 3+ switches

operate with one PSU - installing a
second PSU provides redundancy.
Internal PSUs eliminate the need
for an external Redundant Power
Supply (RPS) that occupies valuable
rack space. Built-in redundancy
guarantees the continued delivery of
essential services.

High Availability IPv6 | 9

About Allied Telesis Inc.

Allied Telesis is a world class leader in delivering IP/Ethernet network solutions to the
global market place. We create innovative, standards-based IP networks that seamlessly
connect you with voice, video and data services.

Enterprise customers can build complete end-to-end networking solutions through
a single vendor, with core to edge technologies ranging from powerful 10 Gigabit
Layer 3 switches right through to media converters.

Allied Telesis also offer a wide range of access, aggregation and backbone solutions
for Service Providers. Our products range from industry leading media gateways
which allow voice, video and data services to be delivered to the home and
business, right through to high-end chassis-based platforms providing significant
network infrastructure.

Allied Telesis’ flexible service and support programs are tailored to meet a wide
range of needs, and are designed to protect your Allied Telesis investment well into
the future.

For further information visit us online at alliedtelesis.com

North America Headquarters | 19800 Nor th Creek Park way | Suite 100 | Bothell | WA 98011 | USA | T: [phone] | F: [phone]
Asia-Pacic Headquarters | 11 Tai Seng Link | Singapore | 534182 | T: [phone] | F: [phone]
EMEA & CSA Operations | Antareslaan 18 | 2132 JE Hoofddorp | Netherlands | T: [phone] | F: [phone]

alliedtelesis.com

© 2012 Allied Teles is, Inc. All r ights reser ved. Infor mation in th is document is su bject to chan ge without n otice. All comp any names, lo gos, and prod uct designs t hat are trad emarks or r egistere d trademar ks are the p ropert y of their respe ctive owne rs.
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