access point redundancy - mum - mikrotik user...

Access Point Redundancyby Lorenzo Busatti

MikroTik User Meeting in USA

Las Vegas, October 13-14, 2011

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Lorenzo Busatti

Grifonline S.r.l., Grosseto – ITALY

ISP for more 15 years, WISP for more 6 years

MikroTik Certified Trainer / Consultant

• For all courses: MTCNA, MTCWE, MTCRE,

MTCTCE, MTCUME, MTCINE

• Specialization: Wireless, Routing

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About me

Presentation Objectives

•Raise awareness on the issue of

redundancy of access points used

in base stations

•Provide a starting point for a

setup

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Uptime!

•The Uptime of a wireless service

should be 100%.

•The more is closer to 100% the

more the users will be happy

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The commons

operations in a Wireless

Network

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Power Supply

• It’s easy to double the power

supplies, UPS, large batteries, for

having "power" up to a week.

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Links Redundancy

•Thanks to RSTP or OSPF or MPLS

(for the masses thanks to MikroTik ☺)

your network is not a “tree”

anymore. All links are now

“doubled” and the network is

more reliable.

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Internet Backbone

•With BGP it’s easy to setup more

than one Internet upstream

• If one of the peers goes down

there is another one(s).

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Basic Network Example

Clients

AccessPoint

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Internet

Router

Link

Advanced Network Example

Clients

AccessPoint

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Internet

peer 1

BGPRouter

Internet

peer 2

Double Links

Advanced Network Example

Clients

AccessPoint

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Internet

peer 1

BGPRouter

Internet

peer 2

Double Links

Why just a SINGLE AP ????

Advanced Network Example

ClientsAccessPoints

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Internet

peer 1

BGPRouter

Internet

peer 2

Double Links

Two is better than one!!!

How to manage

double APs

(Failover)

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RouterOS HowTo

•Thanks to RouterOS's features it is

possible to have “hot spare” APs

in few easy steps.

•And thanks to his flexibility there

are “lot” of ways to do this.

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Planning the behavior

•How do you want your “spare” AP

will react?

•Don’t exist exact rules, with

RouterOS you are free to decide.

• I will show you just one example,

a starting point.

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Behavior Example

ClientsAccessPoints

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• We want the “spare” AP will

have the wireless OFF when

the main AP is working.

• We don’t want both APs with

wireless cards ON at the same

time.

• We want a “protection” from

ethernet disconnections or

failures, when the routers are

powered ONM

AIN

AP

SP

AR

E A

P

Behavior Example

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• For this behavior example we need a

“reference” (or fixed) point in the network.

• We can choose the internet gateway.

• If the internet gateway will fail nobody can use

the network.

• We will use just some simple “Ping” and

scripts for doing all the job.

Behavior Example

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MA

IN A

P

SP

AR

E A

P

InternetGateway

Netwatch

At startup:WLAN ON

At startup:WLAN OFF

If I can’t ping the gateway I can

turn off the WLAN

If I can’t ping the Main AP but I can ping the gateway, I

can turn on the WLAN

The RouterOS Setup (MAIN AP)

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/tool netwatch

add comment="Ping the Gateway" \

host=192.168.1.1 interval=2s timeout=1s \

down-script="interface wireless disable 0" \

up-script="interface wireless enable 0"

/system script

add name=enablewlan source="/interface wireless enable wlan1"

/system scheduler

add name=enablewlan on-event=enablewlan start-time=startup

The RouterOS Setup (SPARE AP)

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/tool netwatch

add comment="Ping the Gateway" host=192.168.1.1 interval=2s timeout=1s \

down-script="interface wireless disable 0"

add comment="Ping Master AP" host=192.168.1.2 interval=2s timeout=1s \

up-script="interface wireless disable 0"

/system script

add name=disablewlan source="/interface wireless disable wlan1"

add name=checkAP source="\

:if (([/tool netwatch get 1 status ] = "down") && ([/tool netwatch get 0 status ] = "up")) do={ \

:if ([/interface wireless get 0 disabled ] = true ) do={ \

[/interface wireless enable 0] } \

}"

/system scheduler

add name=disablewlan start-time=startup on-event=disablewlan

add name=checkAP start-time=startup interval=3s on-event=checkAP

End of the Settings!

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• Yes, we’re done all the settings for this basic

example (as a starting point!).

Live Demo

The “Gateway”192.168.1.1/24

My Laptop192.168.1.4/24

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The “Main” AP192.168.1.2/24

A Wireless“Client”

192.168.1.5/24

The “Spare” AP192.168.1.3/24

In the Real Environments

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Thankyou!

Q & A

http://training.grifonline.it

training@grifonline.it

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