Webinar topic: OSPF Basics with Mikrotik Presenter: Achmad Mardiansyah In this webinar series, We are discussing OSPF Basics with Mikrotik Please share your feedback or webinar ideas here: http://bit.ly/glcfeedback Check our schedule for future events: https://www.glcnetworks.com/schedule/ Follow our social media for updates: Facebook, Instagram, YouTube Channel, and telegram

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OSPF basics with
GLC webinar, 11 january 2018
Achmad Mardiansyah
achmad@glcnetworks.com
GLC Networks, Indonesia
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Agenda
● Introduction
● Routing basics
● Routing on Mikrotik
● Example
● Q & A
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What is GLC?
● Garda Lintas Cakrawala (www.glcnetworks.com)
● An Indonesian company
● Located in Bandung
● Areas: Training, IT Consulting
● Mikrotik Certified Training Partner/Consultant/Distributor
● Ubiquiti Certified Trainer/Consultant
● Linux foundation Certified
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About GLC webinar?
● First webinar: january 1, 2010 (title:
tahun baru bersama solaris - new year
with solaris OS)
● As a sharing event with various topics:
linux, networking, wireless, database,
programming, etc
● Regular schedule: every 2 weeks
● Irregular schedule: as needed
● Checking schedule:
http://www.glcnetworks.com/schedule
● You are invited to be a presenter
○ No need to be an expert
○ This is a forum for sharing: knowledge,
experiences, information
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Trainer Introduction
● Name: Achmad Mardiansyah
● Base: bandung, Indonesia
● Linux user (since 1999), Mikrotik user (since 2007),
ubnt user (since 2011),
● Certified Trainer (Mikrotik, Ubiquiti, Linux)
● Certified Consultant
● Website contributor: achmadjournal.com, mikrotik.tips,
asysadmin.tips
● Work: Telco engineer, Sysadmin, PHP programmer,
and Lecturer
● More info:
http://au.linkedin.com/in/achmadmardiansyah
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Please introduce yourself
● Your name
● Your company/university?
● Your networking experience?
● Your mikrotik experience?
● Your expectation from this course?
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Routing basics
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What is router
● A network device that is used to forward packets
● Layer 3 device -> will check Layer 3 header
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Typical connection (physical)
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R2
R1
R3
● Router connects layer 2
segments
● Router works on layer 3
● Meaning, each layer 2
segment has network ID

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Typical connection (logical) and routing table
Routing table:
● A table at router that is used to forward packet
● Available on every devices (router and host)
● Entry is executed sequentially
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192.168.0.0/26
R1
192.168.0.1/26
192.168.0.3/26
192.168.0.2/26
R3
R2
192.168.1.0/24
192.168.2.0/24
192.168.3.0/24
192.168.3.3/24
192.168.3.9/24
192.168.2.9/24
192.168.2.2/24
192.168.1.1/24
192.168.1.9/24
destination gateway
192.168.0.0/26 direct
192.168.1.0/24 direct
192.168.2.0/24 192.168.0.2
192.168.3.0/24 192.168.0.3
192.168.16.3/32 192.168.0.2
0.0.0.0/0 (default gw) 192.168.0.3

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Priority on routing table
● Router will analyse the destination IP address of incoming packets
● Router will rearrange the routing entry and put priority
○ Longest prefix wins
○ Lowest distance wins
● 0.0.0.0/0 is known as default route -> lowest priority
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destination gateway
192.168.0.0/26 direct
192.168.1.0/24 direct
192.168.2.0/24 192.168.0.2
192.168.3.0/24 192.168.0.3
192.168.16.3/32 192.168.0.2
0.0.0.0/0 192.168.0.3
destination gateway
192.168.16.3/32 192.168.0.2
192.168.0.0/26 direct
192.168.1.0/24 direct
192.168.2.0/24 192.168.0.2
192.168.3.0/24 192.168.0.3
0.0.0.0/0 192.168.0.3

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How the routing table works (R1)?
● It works like a firewall: match and action
● You should think in binary to understand how it works
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destination gateway
192.168.16.3/32
11000000 10101000 00001000 00000011
192.168.0.2
192.168.0.0/26
11000000 10101000 00000000 00
direct
192.168.1.0/24
11000000 10101000 00000001
direct
192.168.2.0/24
11000000 10101000 00000010
192.168.0.2
192.168.3.0/24
11000000 10101000 00000011
192.168.0.3
0.0.0.0/0
(no match)
192.168.0.3

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A packet arrived at R1… (example 1)
Destination IP address of the packet is 192.168.16.3, which gateway do we use?
A: 192.168.16.3 = (11000000 10101000 00001000 00000011)
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destination gateway
192.168.16.3/32
11000000 10101000 00001000 00000011
192.168.0.2
192.168.0.0/26
11000000 10101000 00000000 00
direct
192.168.1.0/24
11000000 10101000 00000001
direct
192.168.2.0/24
11000000 10101000 00000010
192.168.0.2
192.168.3.0/24
11000000 10101000 00000011
192.168.0.3
0.0.0.0/0 192.168.0.3

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A packet arrived at R1… (example 2)
Destination IP address of the packet is 192.168.2.6, which gateway do we use?
A: 192.168.2.6 = (11000000 10101000 00000010 00000110)
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destination gateway
192.168.16.3/32
11000000 10101000 00001000 00000011
192.168.0.2
192.168.0.0/26
11000000 10101000 00000000 00
direct
192.168.1.0/24
11000000 10101000 00000001
direct
192.168.2.0/24
11000000 10101000 00000010
192.168.0.2
192.168.3.0/24
11000000 10101000 00000011
192.168.0.3
0.0.0.0/0 192.168.0.3

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A packet arrived at R1… (example 3)
Destination IP address of the packet is 192.168.8.6, which gateway do we use?
A: 192.168.8.6 = (11000000 10101000 00001000 00000110)
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destination gateway
192.168.16.3/32
11000000 10101000 00001000 00000011
192.168.0.2
192.168.0.0/26
11000000 10101000 00000000 00
direct
192.168.1.0/24
11000000 10101000 00000001
direct
192.168.2.0/24
11000000 10101000 00000010
192.168.0.2
192.168.3.0/24
11000000 10101000 00000011
192.168.0.3
0.0.0.0/0 192.168.0.3

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Administrative distance (analogy)
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JAKARTA 100 km
BANDUNG 120 km
BANDUNG 90 km
SURABAYA 500 km
SEMARANG 250 km
10.10.10.0/24 192.168.0.1 10
10.10.20.0/24 192.168.0.2 12
10.10.20.0/24 192.168.0.3 9
10.10.30.0/24 192.168.0.3 50
10.10.40.0/24 192.168.0.4 25

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Administrative distance
● Distance is considered when prefix
length is same
● Lowest distance wins
● Administrative distance policy is
depends on vendor
● Table on the right shows an example of
administrative distance on cisco router
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Static routing
● Entries on routing table is created
manually
● Admin must manage routing table
in all routers
● Admin have full control
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192.168.0.0/26
R1
192.168.0.1/26
192.168.0.3/26
192.168.0.2/26
R3
R2
192.168.1.0/24
192.168.2.0/24
192.168.3.0/24
192.168.3.3/24
192.168.3.9/24
192.168.2.9/24
192.168.2.2/24
192.168.1.1/24
192.168.1.9/24
destination gateway
192.168.0.0/26 direct
192.168.1.0/24 direct
192.168.2.0/24 192.168.0.2
192.168.3.0/24 192.168.0.3
192.168.16.3/32 192.168.0.2
0.0.0.0/0 192.168.0.3

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Dynamic routing
● Entries on routing table is created
automatically using routing protocol
(RIP, OSPF, BGP)
● Admin must have a good
knowledge about routing protocol
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192.168.0.0/26
R1
192.168.0.1/26
192.168.0.3/26
192.168.0.2/26
R3
R2
192.168.1.0/24
192.168.2.0/24
192.168.3.0/24
192.168.3.3/24
192.168.3.9/24
192.168.2.9/24
192.168.2.2/24
192.168.1.1/24
192.168.1.9/24
destination gateway
192.168.0.0/26 direct
192.168.1.0/24 direct
192.168.2.0/24 192.168.0.2
192.168.3.0/24 192.168.0.3
192.168.16.3/32 192.168.0.2
0.0.0.0/0 192.168.0.3

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Important to note
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● Currently, routing is done one-way only
● Forwarding process on router is based on destination IP address
● There is no guarantee incoming path is similar to outgoing path
● We can only control outgoing forwarding
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192.168.0.0/26
R1
192.168.0.1/26
192.168.0.3/26
192.168.0.2/26
R3
R2
192.168.1.0/24
192.168.2.0/24
192.168.3.0/24
192.168.3.3/24
192.168.3.9/24
192.168.2.9/24
192.168.2.2/24
192.168.1.1/24
192.168.1.9/24

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Routing on Mikrotik
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Where routing table lookup happens?
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Static route on mikrotik
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Static route means: routing entry is provisioned manually
● Add default route:
/ip route add dst-address=0.0.0.0/0 gateway=192.168.0.3 distance=250
check-gateway=ping
● Add specific route:
/ip route add dst-address=192.168.2.0/24 gateway=192.168.0.2 distance=250
check-gateway=ping

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Dynamic routing on mikrotik (RIP)
● add RIP interface:
/routing rip interface add interface=ether2
/routing rip interface add interface=ether1
● add networks to advertise to other routers
/routing rip network add network=192.168.0.0/26
/routing rip network add network=192.168.1.0/24
Once RIP is running on every router:
● Each router will send its routing table to neighbor router
● This routing table update happens periodically
● When all router get full routing table of the network -> convergence state
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Interested? Just come to our training...
● Topics are arranged in systematic and logical way
● You will learn from experienced teacher
● Not only learn the materials, but also sharing experiences, best-practices, and
networking
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End of slides
● Thank you for your attention
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