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74007400Samsung Confidential & Proprietary InformationCopyright 2006, All Rights Reserved.

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OfficeServOfficeServ 7x00 7x00Enterprise IP Solutions

Quick Install Guide- Data Server –

L3 Routing

Mar, 2006

OfficeServ Lab.

Samsung Electronics Co., Ltd.


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ContentsContents

Static Route ConfigurationRIP Configuration

OSPF Configuration

L3 Routing Overview


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Overview

Static routing is fine if the network is small, there is a single

connection point to other networks, and there are no redundant

routes. If any of these conditions is false, dynamic routing is

normally used.

Look at the dynamic routing protocols used by routers to

communicate with each other.

1. Introduction


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Overview

2. IGP 와 EGP -. IGP (Interior Gateway Protocol)

. Routing protocol to communicate between the routers in each AS. . RIP (Routing Information Protocol) . OSPF (Open Shortest Path First)

-. EGP (Exterior Gateway Protocol) . Routing protocols that are used between the routers in different ASs. . BGP (Border Gateway Protocol)

ASASASAS

IGPIGP IGPIGP

EGPEGP


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Overview

-. Popular routing protocols


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Overview

-. Autonomous systems

Interior routingInterior routing Exterior routingExterior routing


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Overview

R 172.16.8.0 [120/2] via 172.16.7.9, 00:00:23, eth0

R -- How the route was learned (RIP)

172.16.8.0 -- Destination logical network or subnet

120 -- Administrative distance

/2 -- Metric Value

00:00:23 -- Age of entry

eth0 -- outgoing interface

3. Routing information

-. Example

-. Metric If there are multiple paths within the AS from a router to a network, the router selects the path with the smallest hop count.

-. RIP : Hop Counts -. OSPF : Bandwidth, Cost, ….


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Overview

-. Administrative distance


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Overview

4. Static Route (example)

130.100.1.1/24

130.120.1.1/24

130.120.1.2/24 130.130.1.1/24130.130.1.2/24

130.140.1.1/24

130.140.1.2/24

130.150.1.1/24

130.150.1.2/24

B

A

C

D

E

e1

e0

e0s0 s0

e0 e0

e1

e1

Router B

ip route 130.100.1.0 255.255.255.0 130.120.1.1 ip route 130.140.1.0 255.255.255.0 130.130.1.2 ip route 130.150.1.0 255.255.255.0 130.130.1.2


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Overview

5. RIP

• Use UDP datagram• UDP datagram Format

20 bytes 8bytes

IP header UDP headerRIP

message

• Metric: Hop Counts

• Hop Count’s limit : 15


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Overview

5. RIP

• is based on distance vector routing, which uses the Bellman-Ford algorithm for calculating the routing tables.

• Distance Vector Routing– each router periodically shares its knowledge about the entire

internet with neighbors– the operational principles of this algorithm

1. Sharing knowledge about the entire autonomous system

2. Sharing only with neighbors

3. Sharing at regular intervals (ex, every 30 seconds)

Distance Vector Routing Table


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Overview

5. RIP

Command(1-6) Version(1) (must be zero)

Address family(2) (must be zero)

32-bit IP address

(must be zero)

(must be zero)

Metric(1-16)(up to 24 more routes, with same format as previous 20 bytes)

-. RIPv1 message format

Command : request (1) or response (2)Version of RIPv1 : 1Address : destination network address Distance : defining the hop count from the advertising router to the destination network


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Overview

5. RIP

-. RIPv2 message format

command(1-6) Version(2) routing domain

address family(2) Routing tag

32-bit IP address

32-bit subnet mask

32-bit next-hop IP address

metric(1-16)

(up to 24 more roues, with same format as previous 20 bytes)

20bytes

Route Tag : carrying information such as the autonomous system number Subnet mask : carrying the subnet mask Next-hop address : showing the next hop


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Overview

5. RIP

• Timers in RIP

– Periodic timer : controlling the advertisements of regular update messages

– expiration timer : governing the validity of a route

– the garbage collection timer : advertising the failure of a route

• Periodic timer

– controlling the advertising of regular update messages

– using random number between 25 to 35 seconds


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Overview

5. RIP

• Expiration timer– In normal situation, the new update for a route occurs every 30 seconds– But, if there is a problem on an Internet and no update is received within the

allotted 180 seconds, the route is considered expired and the hop count of the route is set to 16.

– Each router has its own expiration timer.

• Garbage Collection Timer– When the information about a route becomes invalid, the router continues to

advertise the route with a metric value of 16 and the garbage collection timer is set to 120 sec for that route

– When the count reaches zero, the route is purged from the table.


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Overview

5. RIP

Timer Example

A routing table has 20 entries. It does not receive information about five routes for 200 seconds. How many timers are running at this time?

The timers are listed below:

Periodic timer: 1

Expiration timer: 20 - 5 = 15

Garbage collection timer: 5


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Overview

5. RIP

255.255.255.255255.255.255.255

255.255.255.255

RIPv1(Broadcast)

224.0.0.9224.0.0.9

RIPv2(Multicast)

-. Routing update


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Overview

5. RIP

-. Routing update


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Overview

5. RIP (Example)

130.100.1.1/24

130.120.1.1/24

130.120.1.2/24 130.130.1.1/24130.130.1.2/24

130.140.1.1/24

130.140.1.2/24

130.150.1.1/24

130.150.1.2/24

B

A

C

D

E

e1

e0

e0s0 s0

e0 e0

e1

e1

Router A

router rip

network 130.100.1.0/24

network 130.120.1.0/24

Router B

router rip

network 130.120.1.0/24

network 130.130.1.0/24

Router D

router rip

network 130.140.1.0/24

network 130.150.1.0/24

Router E

router rip

network 130.150.1.0/24

Router C

router rip

network 130.130.1.0/24

network 130.140.1.0/24


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Overview

6. OSPF

Area 0

Area 1 Area n

Backbone routerArea border router

Internal router

In a distance-vector protocol, each router sends and receives the messages which contain a vector of distances.(hop

counts)

In a link-state protocol, each router actively tests the status of

its link to each of its neighbors, sends this info. to its otherneighbors, which then propagate it throughout the AS.

From a practical perspective, the important difference is that a

link-state protocol will always converge faster thana distance vector protocol.


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Overview

6. OSPF

Features that make OSPF superior to RIP

– OSPF can calculate a separate set of routes for each IP type-of-service.

– Each interface is assigned a dimensionless cost.(throughput, RTT, etc.)

– Load balancing: When several equal-cost routes to a destination, OSPF distributes traffic equally among the routes.

– OSPF supports subnets.

– Point-to-point links bet’n routers do not need an IP addr. at each end.

– A simple authentication scheme can be used.

– OSPF uses multicasting instead of broadcasting.


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Overview

6. OSPF

Function/Feature RIPv1 RIPv2 OSPFStandard number RFC 1058 RFC 1723 RFC 2178

Link-state protocol No No Yes

Large range of metricsHop count(16 = infinity)Hop count(16 = infinity)Yes, based on 1-65,535

Update policyRouting table every 30

secondsRouting table every 30

secondsWhen link state change

Or every 30 minutes

Update address Broadcast Broadcast, multicast multicast

Dead interval 300 seconds total 300 seconds total Variable settings

Supports authentication No Yes Yes

Convergence timeMedia delay +Dead interval

Variable(based on Number of routers * DI)

Variable(based on Number of router * DI)

Variable-length subnets NO Yes Yes

Type of service(TOS) NO NO Yes

Network diameter 15 hops 15 hops 65,355 possible

RIP via OSPF


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Overview

6. OSPF

OSPF Message Format


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Overview

6. OSPF

Hierarchical Routing• Consists of areas and autonomous systems• Minimize routing update traffic

Area 0

Area 1 Area 2

Autonomous System


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Overview

6. OSPF

The Backbone and Virtual Links

• Backbone center of communication

• Virtual link provide path to backbone

• Avoid configuring virtual link if possible

Area 0Area 1

Area 2

Area 3


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Overview

6. OSPF

Link-State DB & Advertisement• Link-State DB

– represents the network topology– shared with OSPF routers in same area

• LSA (Link-State Advertisement)– sourced by router connected to link– flooded by all other routers in area– transmitted at each link-state change

LSA


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Overview

6. OSPF

Link-State Advertisement Operation

LSALSA

LSA

LSA receivedIs entry intopologicaldatabase

reset timer for entry

add to database

flood LSA

run SPF to caculatenew table

Y

N


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Overview

6. OSPF

Type of Link-State Packets

router

network

summary

external

ABR ASBR

externalASO - OSPF derived intra-area (router)

IA - inter-area (summary)E1 - type 1 externalE2 - type 2 external

OSPF routing table


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Overview

6. OSPF

130.100.1.1/24

130.120.1.1/24

130.120.1.2/24 130.130.1.1/24130.130.1.2/24

130.140.1.1/24

130.140.1.2/24

130.150.1.1/24

130.150.1.2/24

B

A

C

D

E

e1

e0

e0s0 s0

e0 e0

e1

e1

Router B

router ospf

network 130.130.1.0/24 area0

network 130.120.1.0/24 area1

Router C

router ospf

network 130.130.1.0/24 area0

network 130.140.1.0/24 area2

Router D

router ospf

network 130.140.1.0/24 area2

network 130.150.1.0/24 area2

Area 1

Area 0Area 2

Configuration Example


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Overview

6. OSPF

Virtual Link Example

130.100.1.1/24

130.120.1.1/24

130.120.1.2/24 130.130.1.1/24130.130.1.2/24

130.140.1.1/24

130.140.1.2/24

130.150.1.1/24

130.150.1.2/24

B

A

C

D

E

e1

e0

e0s0 s0

e0 e0

e1

e1

Area 1

Area 0Area 2

Area 3

Router C

router ospf 100

network 130.130.1.0 area 0


area 2 virtual-link 130.150.1.1

Router D

router ospf 100



area 2 virtual-link 130.140.1.1


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1. Configuration

-. Configure routing entry using static route.

-. We can use Default GW option of Interface

Static Route

Network

165.213.100.0

165.213.89.238

165.213.89.237

ip route 165.213.100.0 255.255.255.0 165.213.89.238

or

ip route 165.213.100.0/24 165.213.89.238


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Static Route

2. Static Route command & status -. For static route using Input Configuration Command -. Current Configuration Status

add static route


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1. Configuration

RIP Configuration

PC #110.0.0.100

10.0.0.0/24

OS7400 #1 192.168.30.0/24 OS7400 #2 172.16.0.0/24

30.0.0.0/24PC #230.0.0.100

OS7400 #3

OS7400 #1 configuration router rip version 2 (or version 1) network 192.168.30.0/24 redistribute connected

OS7400 #2 configuration router rip version 2 (or version 1) network 172.16.0.0/24 network 192.168.30.0/24 redistribute connected



OS7400 #2 configuration router rip version 2 (or version 1) network 172.16.0.0/24 network 192.168.30.0/24 redistribute connected


OS7400 #2 Routing TableR>* 10.0.0.0/8 [120/2] via 192.168.30.1, eth0, 00:01:23R>* 30.0.0.0/8 [120/2] via 172.16.0.2, eth1, 00:02:02C>* 127.0.0.0/8 is directly connected, loC>* 172.16.0.0/24 is directly connected, eth1C>* 192.168.30.0/24 is directly connected, eth0

OS7400 #3 Routing TableR>* 10.0.0.0/8 [120/3] via 172.16.0.1, eth0, 00:03:09C>* 30.0.0.0/24 is directly connected, eth1C>* 127.0.0.0/8 is directly connected, loC>* 172.16.0.0/24 is directly connected, eth0R>* 192.168.30.0/24 [120/2] via 172.16.0.1, eth0, 00:01:08

OS7400 #2 Routing TableR>* 10.0.0.0/8 [120/2] via 192.168.30.1, eth0, 00:01:23R>* 30.0.0.0/8 [120/2] via 172.16.0.2, eth1, 00:02:02C>* 127.0.0.0/8 is directly connected, loC>* 172.16.0.0/24 is directly connected, eth1C>* 192.168.30.0/24 is directly connected, eth0

OS7400 #3 Routing TableR>* 10.0.0.0/8 [120/3] via 172.16.0.1, eth0, 00:03:09C>* 30.0.0.0/24 is directly connected, eth1C>* 127.0.0.0/8 is directly connected, loC>* 172.16.0.0/24 is directly connected, eth0R>* 192.168.30.0/24 [120/2] via 172.16.0.1, eth0, 00:01:08


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2. RIP command and status

RIP Configuration

Example) Configuration of OS7400 #3 -. RIP version 2 -. Redistribute Connected route (address of Network Interface)


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1. Configuration

OSPF Configuration

PC #110.0.0.100

10.0.0.0/24

OS7400 #1192.168.30.0/24 OS7400 #2 172.16.0.0/24

30.0.0.0/24PC #230.0.0.100

OS7400 #3

OS7400 #1 configuration router ospf network 192.168.30.0/24 area 0 redistribute connected

OS7400 #2 configuration router ospf network 172.16.0.0/24 area 0 network 192.168.30.0/24 area 0 redistribute connected



OS7400 #2 configuration router ospf network 172.16.0.0/24 area 0 network 192.168.30.0/24 area 0 redistribute connected


OS7400 #2 Routing TableO>* 10.0.0.0/24 [110/20] via 192.168.30.1, eth0, 00:04:21O>* 30.0.0.0/24 [110/20] via 172.16.0.2, eth1, 00:02:22C>* 127.0.0.0/8 is directly connected, loO 172.16.0.0/24 [110/10] is directly connected, eth1, 00:04:22C>* 172.16.0.0/24 is directly connected, eth1O 192.168.30.0/24 [110/10] is directly connected, eth0, 00:04:22C>* 192.168.30.0/24 is directly connected, eth0

OS7400 #3Routing TableO>* 10.0.0.0/24 [110/20] via 172.16.0.1, eth0, 00:02:31C>* 30.0.0.0/24 is directly connected, eth1C>* 127.0.0.0/8 is directly connected, loO 172.16.0.0/24 [110/10] is directly connected, eth0, 00:03:10C>* 172.16.0.0/24 is directly connected, eth0O>* 192.168.30.0/24 [110/74] via 172.16.0.1, eth0, 00:02:32

OS7400 #2 Routing TableO>* 10.0.0.0/24 [110/20] via 192.168.30.1, eth0, 00:04:21O>* 30.0.0.0/24 [110/20] via 172.16.0.2, eth1, 00:02:22C>* 127.0.0.0/8 is directly connected, loO 172.16.0.0/24 [110/10] is directly connected, eth1, 00:04:22C>* 172.16.0.0/24 is directly connected, eth1O 192.168.30.0/24 [110/10] is directly connected, eth0, 00:04:22C>* 192.168.30.0/24 is directly connected, eth0

OS7400 #3Routing TableO>* 10.0.0.0/24 [110/20] via 172.16.0.1, eth0, 00:02:31C>* 30.0.0.0/24 is directly connected, eth1C>* 127.0.0.0/8 is directly connected, loO 172.16.0.0/24 [110/10] is directly connected, eth0, 00:03:10C>* 172.16.0.0/24 is directly connected, eth0O>* 192.168.30.0/24 [110/74] via 172.16.0.1, eth0, 00:02:32


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2. OSPF command and status

OSPF Configuration

Example) Configuration of OS7400 #3 -. OSPF area 0 -. Redistribute connected route (address of Network Interface)

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