Intro to Network Design

Introduction

to

Network

Design

Tina Simpson

1

Table of Contents

1. INTRODUCTION....................................................................................................................10

2. DESIGN AND DOCUMENT THE ADDRESSING SCHEME..............................................11

1. THE PRODUCTION LAN....................................................................................................................12

2. THE R & D LAN................................................................................................................................14

3. THE SALES LAN................................................................................................................................15

4. THE PRODUCTION TO SALES POINT-TO-POINT LINK/LAN....................................................16

5. THE PRODUCTION TO R & D POINT-TO-POINT LINK/LAN...................................................16

6. THE FINAL NETWORK IP ADDRESSING SCHEME......................................................................17

3. PRODUCTION ROUTER CONFIGURATION SETTINGS..................................................19

4. LAYER 3 CONNECTIVITY BETWEEN HOSTS..................................................................20

5. PRODUCTION ROUTER ROUTING TABLE.......................................................................21

5.1 IDENTIFIED NETWORKS....................................................................................................................21

5.2 METRICS..............................................................................................................................................22

6. SWITCHES, ROUTERS AND DATA-ENCAPSULATION..................................................23

6.1 ROUTERS..............................................................................................................................................23

6.2 SWITCHES............................................................................................................................................24

6.3 DATA-ENCAPSULATION...................................................................................................................24

7. RIP, EIGRP AND OSPF...........................................................................................................26

7.1 RIP1/RIP2...........................................................................................................................................26

7.2 EIGRP..................................................................................................................................................26

7.3 OSPF....................................................................................................................................................28

3. CONCLUSIONS/RECOMMENDATIONS.............................................................................29

4. REFERENCES..........................................................................................................................30

5. APPENDICES INDEX.............................................................................................................31

2

3

1. Introduction

As a network manager for a retail company, the delivery of 3 new routers to establish the

topography diagram below requires the configuration of each of the routers with a basic setup

(Reed, 2011). The address scheme provided of 172.16.0.0/12 is a Private IP Address space

for use on an internal network whose addresses are not intended to be routed across the

internet as defined by RFC1918 (Rekhter, et al – 1996). The IETF (Internet Engineering

Task Force) directed the IANA (Internet Assigned Numbers Authority ) to reserve three

blocks of private address space for the use of private networks as follows:

10.0.0.0 - 10.255.255.255 (10/8 prefix)

172.16.0.0 - 172.31.255.255 (172.16/12 prefix)

192.168.0.0 - 192.168.255.255 (192.168/16 prefix)

Required Network Topology Diagram for the Private Network

4

2. Design and Document the Addressing Scheme

In deciding the correct IP Address scheme allocation, consideration for possible future

expansion has been included in this network. In a real scenario, historical data, if available,

can be reference to reflect historical growth, and assist in predicting future growth. If

contingencies are not included for future growth, a network manager would have to redo a

network design again because of poor planning in the initial setup stages, which is not only

time consuming, but also disruptive to the network whilst the re-configuration is in progress

and until the network has once again converged (Newcomer – 2003).

In order to create an efficient addressing scheme that meets the host requirements per router

from the topography requirements provided for this network, and the given Class B IP

address of 172.16.0.0/12, you need to calculate the number of subnets required, followed by

the number of hosts required per subnet, in descending order (Rekhter, et al. - 1996).

# Hostname Interface Number of Hosts

0 Production Fa0/0 490

1 R & D Fa0/0 220

2 Sales Fa0/0 120

3 WAN link Production to Sales

S0/0/0& S0/0/0 2

4 WAN link Production to R & D

S0/0/1 & S0/0/0 2

The IP address we have been given is broken down into 12 bits used for the network address

and 15 bits are available for subnet and host bits as shown below:

(n = network bits, h = host bits available)

Title Type IP Address

IP Address

Decimal 172.16.0.0 / 12Binary 10101100.00010000.00000000.00000000

Class Bit Usage

nnnnnnnn.nnnnhhhh.hhhhhhhh.hhhhhhhh

Subnet MaskDecimal 255.240.0.0Binary 11111111.11110000.00000000.00000000

We have already calculated that 5 subnets will be required to complete this network

topography, which equates to the need for 3 bytes to be used as Subnets of the Network (2 ^

2 bits= 4 subnets and 2 ^ 3 = 8 Subnets provision where 6 are Usable Host Addresses, plus

5

the Network and the Broadcast Address). This option also allows for future expansion of the

network, such as WAN point-to-point links between R&D and the Sales departments.

1. The Production Lan

The Production Router has the largest IP Address requirement on the Network with 490

hosts, which calculates that 9 bits will be required to fulfil the minimum amount of host

address, where 2 ^ 9 = 512 host addresses with 510 available host addresses (2 ^ 8 = 256

of which 254 are available host addresses, and 2 ^ 10 = 1024 of which 1022 are available

host addresses). Whilst this would leave 20 host addresses available, considering the

current size of the Production Department IP Address demands, and to ensure allowance for

future expansion, 10 host bits will be used to allow a maximum of 1022 host IP Addresses.

This results in there being a possible 6 bits available for subnets, whereby 2 ^ 6 = 64

possible subnets available, giving a network prefix of /22.

(n = network bits, s = subnet bits, h = host bits available)


IP Address

Decimal 172.16.0.0 / 22Binary 10101100.00010000.00000000.00000000

Class Bit Usage

nnnnnnnn.nnnnnnnn.sssssshh.hhhhhhhh

Subnet Mask

Decimal 255.255.252.0Binary 11111111.11111111.11111100.00000000

Wildcard Mask (EIGRP)

Decimal 0.0.3.255 (Reverse subnet mask)

Binary 00000000.00000000.00000011.11111111

With a subnet Mask of the third octet being 252, if you take that away from the Magic

Number of the total no of IP Addresses possible within an Octet of 256 (0 – 255) you can

calculate the steps for each subnet range. i.e. 256 – 252 = 4. This prefix (/22) will provide

2 ^ 10 bits for host address = 1024 (1022 available hosts – with an existing requirement of

490 hosts).

6

This Step Methodology is then used to calculate each Subnet Network Address required for

the topography: -

0th 172.16.0.0 1st 172.16.0.0 + 4 = 172.16.4.0

2nd 172.16.4.0 + 4 = 172.16.8.0 3rd 172.16.8.0 + 4 = 172.16.12.0

4th 172.16.12.0 + 4 = 172.16.16.0 5th 172.16.16.0 + 4 = 172.16.20.0

… and so on up to the 63rd Subnet which has a final host address (broadcast address) of

172.16.255.255 for the network.

The subnet IP Address Ranges would therefore be:-

Network Address

Network Address

First Host Address

Last Host Address

Subnet Broadcast Address

0th

Subnet172.16.0.0 172.16.0.1 172.16.3.254 172.16.3.255

1st Subnet

172.16.4.0 172.16.4.1 172.16.7.254 172.16.7.255

2nd Subnet

172.16.8.0 172.16.8.1 172.16.11.254 172.16.11.255

3rd Subnet

172.16.12.0 172.16.12.1 172.16.15.254 172.16.15.255

4th Subnet

172.16.16.0 172.16.16.1 172.16.19.254 172.16.19.255

5th Subnet

172.16.20.0 172.16.20.1 172.16.23.254 172.16.23.255

6th Subnet

172.16.24.0 and so on

Whilst this IP Address scheme would provide the required number of subnets and host

addresses per router, whilst also allowing for some future expansion of the network, there

would be a large number of wasted host address for the remaining subnets of the network.

For instance, the R & D Department currently only have 220 hosts (1020 – 220 = 800

unused IP Host Addresses); the Sales Department currently only have 120 hosts (1020 –

120 = 900 unused IP Host Addresses); and each point-to-point link will only ever require 2

host IP Addresses (1020 – 2 = 1018 unused IP Host Addresses).

The solution to this problem was resolved by the introduction of CIDR (Classless Inter-

Domain Routing), utilising VLSM (Variable-Length Subnet Masking) (Fuller, et al. –

7

2006) to enable a network to be divided into varying sized subnets to facilitate a networks

topography in the most efficient manner (Fuller, et al. – 1993). This grouping, or ‘cluster

addressing’ was first proposed by Carl-Herbert Rokitansky in 1988

Using CIDR as the rule to create the subnets, the following final Network IP Address

Scheme can be calculated.

Production Lan IP Address Scheme:

Networ

k

Address

Subnet Mask CIDR

Subnet

Mask

First Usable

IP Address

Last Usable IP

Address

Broadcast

Address

172.16.0.

0255.255.252.0 /22 172.16.0.1 172.16.3.254 172.16.3.255

2. The R & D Lan

The next available subnetwork address following the allocation of the Production Lan IP

Addressing Scheme is therefore the next available IP Address, namely 172.16.4.0 (1 host

address up from the boradcast address of the Production Lan Scheme above of

172.16.3.255. Following the same calculation principles above, the following is

ascertained:- 256 – 254 = 2, therefore the next available subnet on this /23 range would be

172.16.6.0. This prefix (/23) will provide 2 ^9 bits for host address = 512 (510 available

hosts – with an existing requirement of 220 hosts).


IP Address

Decimal 172.16.4.0 / 23Binary 10101100.00010000.00000100.00000000

Class Bit Usage

nnnnnnnn.nnnnnnnn.sssssssh.hhhhhhhh




Binary 00000000.00000000.00000001.11111111

This calculates to give the R & D Lan Subnetwork the following Classless IP Addressing Scheme:

Networ Subnet Mask CIDR First Usable Last Usable IP Broadcast

8

k

Address

Subnet

Mask

IP Address Address Address

172.16.4.

0255.255.254.0 /23 172.16.4.1 172.16.5.254 172.16.5.255

3. The Sales LAN

The next available subnetwork address following the allocation of the R & D Lan IP


address up from the boradcast address of the R & D Lan Scheme above of 172.16.5.255.

Following the same calculation principles discussed in the Production Lan calculations, the

following is ascertained:- 256 – 255 = 1, therefore the next available subnet on this /24

range would be 172.16.7.0. This prefix will provide 2 ^8 bits for host address = 256 (254

available hosts – with an existing requirement of 120 hosts).


IP Address

Decimal 172.16.6.0 / 24Binary 10101100.00010000.00000110.00000000

Class Bit Usage

nnnnnnnn.nnnnnnnn.ssssssss.hhhhhhhh




Binary 00000000.00000000.00000000.11111111

This calculates to give the Sales Lan Subnetwork the following Classless IP Addressing Scheme:

Networ

k

Address

Subnet Mask CIDR

Subnet

Mask

First Usable

IP Address

Last Usable IP

Address

Broadcast

Address

172.16.6.

0255.255.255.0 /24 172.16.6.1 172.16.6.254 172.16.6.255

9

4. The Production to Sales Point-to-Point Link/LAN

The next available subnetwork address following the allocation of the Sales Lan IP


address up from the boradcast address of the R & D Lan Scheme above of 172.16.6.255.






IP Address

Decimal 172.16.7.0 / 30Binary 10101100.00010000.00000111.00000000

Class Bit Usage

nnnnnnnn.nnnnnnnn.ssssssss.sssssshh




Binary 00000000.00000000.00000000.00000011

This calculates to give the Production to Sales Lan Subnetwork the following Classless IP Addressing Scheme:

Networ

k

Address

Subnet Mask CIDR

Subnet

Mask

First Usable

IP Address

Last Usable IP

Address

Broadcast

Address

172.16.7.

0255.255.255.252 /30 172.16.7.1 172.16.7.2 172.16.7.3

5. The Production to R & D Point-to-Point Link/LAN

The next available subnetwork address following the allocation of the Production to Sales

Lan IP Addressing Scheme is therefore the next available IP Address, namely 172.16.7.4 (1

host address up from the boradcast address of the R & D Lan Scheme above of 172.16.7.3.



10




IP Address

Decimal 172.16.7.4 / 30Binary 10101100.00010000.00000111.00000100

Class Bit Usage

nnnnnnnn.nnnnnnnn.ssssssss.sssssshh




Binary 00000000.00000000.00000000.00000011

This calculates to give the Production to R & D Lan Subnetwork the following Classless IP Addressing Scheme:

Networ

k

Address

Subnet Mask CIDR

Subnet

Mask

First Usable

IP Address

Last Usable IP

Address

Broadcast

Address

172.16.7.

4255.255.255.252 /30 172.16.7.5 172.16.7.6 172.16.7.7

6. The Final Network IP Addressing Scheme

The final network topology therefore is as follows:

Device Interface IP Address Subnet Mask Default Gateway

Production Fa0/0 172.16.0.1 255.255.252.0 N/A

S0/0/0 172.16.7.5 255.255.255.252 N/A

S0/0/1 172.16.7.1 255.255.255.252 N/A

R & D Fa0/0 172.16.4.1 255.255.254.0 N/A

S0/0/0 172.16.7.6 255.255.255.252 N/A

Sales Fa0/0 172.16.6.1 255.255.255.0 N/A

S0/0/0 172.16.7.2 255.255.255.252 N/A

PC1 Fa0/0 172.16.0.10 255.255.252.0 172.16.0.1

PC2 Fa0/0 172.16.4.10 255.255.254.0 172.16.4.1

PC3 Fa0/0 172.16.6.10 255.255.255.0 172.16.6.1

11

12

3. Production Router Configuration Settings

The documentation for the running configuration for the Production Router is visible at

Appendix 1. This document shows that the Router has been given the hostname of

Production.

Security issues have been addressed with a message of the day banner advising all

administrators that unauthorised access will be prosecuted, which along with a secret

encrypted password set for access to the Exec Privilege area (class) and passwords also set

for the telnet and console connections (cisco).

The Router configuration files show that the the system has been set to not auto-summarise

the ip addresses entered, both the command of ‘no ip domain-lookup’ added to disable DNS

lookup.

Each active interface has been set up with a description and ip address with subnet mask and

no shutdown command. A clockrate of 64000 has also been entered on S0/0/1 which has the

DCE connection of the serial cable linking to the R&D Lan Router.

The router has been configured with the cisco eigrp1 protocol, with a passive interface set on

Fa0/0 to prevent that interface sending out routing table updates across the Network. All

directly connected networks have been declared in the routing table with wildcard masks and

the no auto-summary command to be broadcast across the network . Bandwidth for broadcast

have also been reduced to 68 kbips/sec to reduce the bandwidth used to exchange routing

information and in so doing, reduce the load on the network.

13

4. Layer 3 Connectivity Between Hosts

A simple PDU Packet was sent across the network to confirm all the network was working

correctly. The Events list for this simulation are shown below.

Further details of the Layer 3 connectivity between hosts on each LAN, and evidence

showing the route the data travelled across the network can be seen in the xx found at

Appendix 11.

14

5. Production Router Routing Table

5.1 Identified Networks

The above Production Routing Table shows that the Routing Table has identified 5

Subnets of the network 172.16.0/0/16 with 4 masks.

The first entry shows the directly connected route (identified by the C for connected) of

network 172.16.0.0/22 via the FastEthernet 0/0 port – which is the Production LAN

itself.

The second entry shows the EIGRP protocol learned route (identified by the D for

EIGRP) route of network 172.16.4.0/23 via its Serial Port S0/0/1 to the R & D Network.

The third entry shows the EIGRP protocol learned route (identified by the D for EIGRP)

route of network 172.16.6.0/24 via its Serial Port S0/0/0 to the Sales Network.

15

The fourth entry shows the the directly connected route (identified by the C for

connected) of network 172.16.7.0/30 via the Serial port S0/0/0, which is the point to

point link from the Production Router to the Sales Router.

The fifth entry shows the the directly connected route (identified by the C for connected)

of network 172.16.7.4/30 via the Serial port S0/0/1, which is the point to point link from

the Production Router to the R & D Router.

5.2 Metrics

Directly connected routes are considered the best path and do not generate metrics to

enable the eigrp routing protocol to calculate the best path and so update the table with

any changes to the metrics (best path) for the networks shown.

EIGRP learned routes from routing tanble updates sent by the other routers however, as

they are not directly connected and can therefore change, do show the Administrative

distance and therefore the protocol and metric of the stored best route for that network.

This routing table shows that the EIGRP Administrative Distance vector default of 90

(confirmed by the 90/xxxxxx) for the network of 172.16.6.0/23 is 20514560 and is due to

be updated in 7 secs as shown by the countdown counter of 00:00:07, and can be reached

by sending out packets via the host IP Address of 172.16.7.6 through it’s Serial port

S0/0/1.

The routing table also shows that EIGRP Administrative Distance vector default of 90

(confirmed by the 90/xxxxxx) for the network of 172.16.4.0/24 is 40514560 and is due to

be updated in 3 secs as shown by the countdown counter of 00:00:03, and can be reached

by sending out packets via the host IP Address of 172.16.7.2 through it’s Serial port

S0/0/1.

16

6. Switches, Routers and Data-Encapsulation

6.1 Routers

A router is a specialised computer that send packets of information works at the ‘network

layer’ (Lyaer 3 of the OSI Model) from one router (computer) to another in fractions of time.

It is the routers function to identify and connect other routers, be that between two LAN’s in

a company’s Intranetwork, or via ISP routers across the Internet.

The router is responsible for the forwarding and delivery of packets in the most efficient and

timely manner across these different networks, be that between tow LAN’s in a company’s

intranetwork, or thousands of miles to a network in another country, from sending host to

destination host. A router uses static and dynamic routing protocols to identify networks and

to send packets via the best path to its destination (Graziani, et al.- 2007). The router stores

the best path routes in their routing table, which it then shares with it’s neighbouring routers

on the network to ensure that the packet information is not sent to another router that doesn’t

need it, takes the shortest/best path, and arrives at the correct destination.

A router can be configured to use various Routing Protocols such as Routing Information

Protocol (RIP1/RIP2), Quality of Service (QoS), IGRP/EIGRP (Enhanced Interior Gateway

Routing Protocol, Open Shortest Path First (OSPF), Network Address Translation (NAT)

Multiprotocol Label Switching (MPLS), Hot Standby Router Protocol (HSRP), Border

Gateway Protocol (BGP), Intermediate System-to-Intermediate System (IS-IS), Internet

Protocol (TCP/IP), Connectionless Network Service (CNS) and the Cisco Discovery Protocol

(CDP). Which protocol is implemented depends on the type of router equipment and the

network requirement.

17

6.2 Switches

A switch is a network device that receives messages from any device directly connected to it,

and then transmits it to another device directly connected to it, be that a router or to another

computer on that network.

A switch is basically a connection device for all network segments and network equipment.

It is sometimes referred to as a ‘network bridge’ that connects, processes and routes data at

the OSI Model Layer 2 Data Link Layer to other devices on that network by analysing MAC

Addresses (Graziani – 2007).

Some switches are able to process data at the OSI Layer 3 Network Layer, and are often

referred to as multi-layer switches or Layer-3 switches. A switch has the ability to

‘remember’ which device is connected to which switch port, and to then identify and direct

data received from one switch port to another switch port attached to that switch; or identify

that the data is not meant for that network and send the data out to the router to be processed.

6.3 Data-Encapsulation

Data encapsulation is the process used to contain the information in a protocol within the data

section of another protocol as that data progresses down and up the protocol stack. In the

OSI Layer Model, each layer encapsulates the data immediately above it as data flows down

the stack, whereby the user information is converted to DATA, the data is then converted to

SEGMENTS, the segments are converted to PACKETS (or datagrams); the packets are then

converted to FRAMES, and the frames are then converted to BITS to be sent out across the

media (Troy – 2008):

The 5 steps of Data Encapsulation (Troy – 2008)

18

The High Level Data Link Control Protocol (HDLC) is a link layer, standard default serial

interface encapsulation protocol used to transmit data in Frames across point-to point links,

and multipoint links, between two Cisco Routers. HDLC comprises of a bit-oriented,

synchronous data link layer protocol which specifies a data encapsulation method on

synchronous serial links using frame characters and checksums. HDLC manage the flow at

which the data is sent and operates at the OSI Model Layer 2 Data Link Layer that is

involved in the generating and receiving of the electronic signals, adding data link control

information to the encapsulated Layer 3 Packet containing the source and destination network

addresses, into a frame ready for conversion into bits by the OSI Model Layer 1 Physical

Layer.

The Internet Engineering Task Force (IETF) requires that a Frame Relay Protocol must be for

encapsulation when connecting between or to non-cisco equipment.

19

7. RIP, EIGRP and OSPF

Compare and contrast RIP, EIGRP and OSPF You need to identify any advantages and disadvantages for each protocol. 40 marks

7.1 RIP1/RIP2

RIP is a distance vector routing protocol that uses hop count as its metric, whereby when the

hop count reaches its maximum of 15 hops, the 16 th hop is denoted as unreachable. RIP

broadcast complete routing table information from router to it’s directly connected neighbour

(s) on the network every 30 minutes . Each time a router receives a routing table from its

neighbour, it increments all the learned route hops by 1. Reach router does not know the

exact topology of the intranetwork, so when any topology changes, the routing table updates

and the entire routing table is then sent out across the network. The receiving router then

compares that new routing table information with its existing routing table, updates its own

table, and then sends that updated table back across the network (Graziani – 2007).

Distance Vector protocols are therefore very slow to converge, take up large bandwidth and

load on a network, and are susceptible to routing loops and counting to infinity. Split-

Horizons (not sending information about a route back out of that interface), route poising

(information marked as hop count 15 – unreachable), and hold down timers (routers ignore

network update information for a set period of time while a network converges) can all be

implemented to reduce these issues (Troy – 2008).

7.2 EIGRP

The Enhanced Interior Gateway Routing Protocol (EIGRP) is a Cisco proprietary distance

vector routing protocol released in 1994,predessing the earlier version of Interior Gateway

Routing Protocol (IGRP). EIGRP integrated the capabilities of link-state protocols into

distance vector protocols to increase operational efficiency by containing several protocols

such as Diffusing Update Algorithm (DUAL) to allow routers to determine whether a path

advertised by a neighbor is looped, and to find alternative paths without waiting on updates

from other routers. EIGRP can only operate on CISCO Routers, but can be integrated in a

20

network routing the older version of IGRP because of the ease of comparison of protocol.

EIGRP uses Real Time Transfer Protocol (RTP) to transmit and receive packets to discover

and establish adjacencies, enabling fast convergence and scalability for medium sized

networks. The EIGRP protocol supports both VLSM and CIDR, and uses has 5 packet types,

those being:-

Hello Packets

Update packets

Acknowledgement packets

Query packets

Reply packets

The advantages of the EIGRP algorithm is that it does not carry out periodic updates of

routing tables between its neighbors, but uses a series of packets (listed above) to ensure that

its neighbors are aware of all topography changes in a network. EIGRP therefore requires

less overhead and is faster to converge a network than RIP, is scalable, yet a cheaper

alternative to OSPF protocol established networks.

21

7.3 OSPF

The Open Shortest Path First (OSPF) is a link state routing protocol algorithm that maintains

a complete routing table of the topography of an entire network, using Link State Packets

(LSP’s ) to inform other routers of distant link changes. When the topology changes the first

router to identify the change sends out an LSP just for that change to all the other routers on

that network. All the routers then re-calculate the best path to that affected route and update

their routing table accordingly. The Best path is ascertained using complex bandwidth

analysis which requires more power, memory and bandwidth to process, placing more

demand on the network, rather than the more simplified next hop metric such as the Distance

Vector Protocols use (Graziani – 2007).

The advantage of this algorithm is that convergence on the network is much faster than

distance vector protocols, with changes in the topology triggering the LSP updates to be sent

out, rather than the distance vector protocol topology updates only being sent out every 30

secs. Routing loops are really seen in link-state algorithm networks, but the extra power and

memory required by each router involves more expense and support for a network manager.

Despite this, the ability to scale a link-state network much larger than distance vector

protocols often becomes the main network option for large corporation intranetworks n

(Graziani – 2007).

22

3. Conclusions/Recommendations

When considering and planning the topology for this network, I had the choice to either

produce an IP Addressing Scheme which showed the most efficient scheme and least wastage

of host addresses per submitted Network, or to look at the future network considerations as a

Network Manager would be required to do. As Newcomer (2003) suggested, to have to

redesign an entire network ip addressing scheme because you have not planned enough

makes one look foolish, let alone be a costly and time consuming exercise for both the

business and the network manager.

The scheme I have suggested allows for future growth of the network for each department to

be able to double in size, whilst still leaving many subnetwork IP Addresses available for any

future growth of the Network; for instance the amalgamation of other offices and

departments, or even companies into the infrastructure.

Whilst I could have devised a plan allowing for minimal wastage and used only half of the

allocated host IP Addresses currently assigned to each LAN, in the case of the Production

LAN, there would only be an allowance of growth for 20 additional host IP Addresses,

which when you consider a potential need, for example, additional scanners, pc’s, printers or

faxes, this minimal availability would soon be encompassed into the existing subnetwork and

restrict all future growth for that LAN. The Production LAN also being the largest host IP

Address requirement at 490 hosts, should they require more than the 20 spare IP Addresses

available, the entire network address scheme would need to be re-configured for all the

LAN’s and each individual host over the entire Network and sub networks.

I therefore feel that the Network IP Addressing Scheme was the most sensible and only

realistic option to implement.

23

4. References

Graziani. R & Johnson. A (2007). “Routing Protocols and Concepts”. Cisco Press. Indianapolis.

Fuller, V., Li, T., Yu, J., and Varadhan, K., (1993). “Classless Inter-Domain Routing (CIDR): an Address Assignment and Aggregation Strategy (RFC 1519)”. Available online at: http://www.ietf.org/rfc/rfc1519.txt. (Accessed on 20 April 2012).

Fuller, V., and Li, T., (2006). “Classless Inter-domain Routing (CIDR): The Internet Address Assignment and Aggregation Plan (RFC4632)”. Available online at: http://www.ietf.org/rfc/rfc4632.txt. (Accessed on 20 April 2012).

Newcomer, L., (2003). “Subnetting Made Simple - IP Subnetting without Tables, Tools, or Tribulations”. Available online at: http://www2.yk.psu.edu/~lxn/ist_227/Subnetting%20Made%20Simple.doc (Accessed on 15 March 2012).

Reed, A., (2012). “Assignment Brief: CITN173 Introduction to Network Design”. (shown at the start of this document – click here for link).

Rekhter, Y., Moskowitz, R., Karrenberg, D., Jan de Groot, G., and Lear, E. (1996). “Address Allocation for Private Internets (RFC1918)”. Available online at: http://www.ietf.org/rfc/rfc1918.txt (Accessed on 15 March 2012).

Rokitansky, C., (1988). “Internet Cluster Addressing Scheme and its Application to Public Data Networks, Proc”. 9th International Conference on Computer Communication (ICCC' 88), pp. 482-491, Tel Aviv, Israel.

Troy Technologies (2008). “CCNA 2.0 Study Guide.” Available online at: http://www.docstore.mik.ua/cisco/pdf/TroyTech%20640-07%20CCNA%202.0%20Edt.3.pdf (Accessed on 15 May 2012).

24

http://www.docstore.mik.ua/cisco/pdf/TroyTech%20640-07%20CCNA%202.0%20Edt.3.pdf

http://www.ietf.org/rfc/rfc1918.txt



5. Appendices Index

I. CONFIGURATION FILE FOR PRODUCTION ROUTER...................................................................31

II. EVIDENCE OF LAYER 3 CONNECTIVITY BETWEEN THE NETWORK......................................33

1. The Production Router sends out a hello packet to the Sales Router...............................33

2. The Sales Router Receives the Hello Packet from Production.......................................35

3. The Production Router sends out a Hello Packet to the R & D Router............................36

4. The R & D Router Receives the Hello Packet from the Production Router......................37

5. The R & D Router sends a Hello Packet to the Production Router..................................38

6. The Production Router receives a Hello Packet from the R & D Router..........................39

7. The Sales Router Sends out a Hello Packet to the Production Router..............................40

8. The Production Router receives the Hello Packet from the Sales Router.........................41

25

I. Configuration file for Production Router

Production#show runBuilding configuration...

Current configuration : 1232 bytes!version 12.4no service timestamps log datetime msecno service timestamps debug datetime msecno service password-encryption!hostname Production!enable secret 5 $1$mERr$9cTjUIEqNGurQiFU.ZeCi1!no ip domain-lookup!!interface FastEthernet0/0 description straight through cable link to Production LAN ip address 172.16.0.1 255.255.252.0 duplex auto speed auto!interface FastEthernet0/1 no ip address duplex auto speed auto shutdown!interface Serial0/0/0 description DHE ink between Sales and Production bandwidth 64 ip address 172.16.7.1 255.255.255.252!interface Serial0/0/1 description DCE link between Production and R&D bandwidth 128 ip address 172.16.7.5 255.255.255.252 clock rate 64000!interface Vlan1 no ip address shutdown!router eigrp 1 passive-interface FastEthernet0/0 network 172.16.7.0 0.0.0.3 network 172.16.7.4 0.0.0.3 network 172.16.0.0 0.0.3.255 no auto-summary!ip classless!

26

no cdp run!banner motd ^C********************************************************************WARNING - UNAUTHORISED ACCESS WILL BE PROSECUTED!********************************************************************^C!line con 0 password ciscoline vty 0 4 password cisco login!end

27

II. Evidence of Layer 3 Connectivity between the Network

1. The Production Router Encapsulates and then sends out a hello packet via the Serial port S0/0/0 port to the Sales Router

28

29

2. The Sales Router Receives the Hello Packet from Production

30

3. The Production Router encapsulates and send out a Hello Packet via Serial S0/0/1 to the R & D Router

31

4. The R & D Router Receives the Hello Packet from the Production Router

32

5. The R & D Router Encapsulates and then Sends out a Hello Packet via S0/0/0 to the Production Router

33

6. The Production Router receives a Hello Packet from the R & D Router

34

7. The Sales Router Sends out a Hello Packet via Serial S0/0/0 across the network to the Production Router

35

8. The Production Router receives the Hello Packet from the Sales Router

36

Documents

Intro to Network Design