CCNA: Introduction to Networking and Protocols

CCNA
(CISCO CERTIFIED NETWORK ASSOCIATE)
List of Tables
1. Internetworking
2. Internet Protocols
3. IP Subnetting and Variable Length Subnet Mask
4. Introduction to the Cisco IOS
5. IP Routing
6. Switching
7. IPv4 vs IPv6
Name: Abhishek Parihari
Reg. No. : 11311575

Introduction about NETWORK and PROTOCOL
Network is simply defined as something that connects things together for a specific purpose.
The term network is used in a variety of contexts, including telephone, television, computer,
or even people networks.
A computer network connects two or more devices together to share a nearly limitless range of information and
services, including:
 Documents
 Email and messaging
 Websites
 Databases
 Music
 Printers and faxes
 Telephony and video conferencing
Protocols are rules that govern how devices communicate and share information across a
network. Examples of protocols include:
• IP – Internet Protocol
• HTTP - Hyper Text Transfer Protocol
• SMTP – Simple mailTransfer Protocol

Internetworking Model ( Reference Model )
Open System Interconnection (OSI) reference model was created by the International Organization for Standardization (ISO)
A reference model is a conceptual blueprint of how communications should take place. It addresses all the processes
required for effective communication and divides theses process into logical groupings called layers.
Seven Layers that define the different stages that data must go through to travel from one device to another
over a network.
Application Set
• Layer 7 : Application
( interacts with the operating system or application
whenever the user chooses to transfer files,
read messages or perform other network-related activities)
• Layer 6 : Presentation
(takes the data provided by the Application layer and
converts it into a standard format that the other layers can
understand)
• Layer 5 : Session
(establishes, maintains and ends communication with the
receiving device)
Transport Set
• Layer 4 : Transport
(maintains flow control of data and provides for error checking
and recovery of data between the devices)
• Layer 3 : Network
(The way that the data will be sent to the recipient device is
determined in this layer. Logical protocols, routing and
addressing are handled)
• Layer 2 : Data
(the appropriate physical protocol is assigned to the data. Also,
the type of network and the packet sequencing is defined)
• Layer 1 : Physical
(defines the physical characteristics of the network such as
connections, voltage levels and timimg)

TCP(Transmission Control Protocol) UDP(User Datagram Protocol)
Protocol No. - 6 Protocol No. - 17
Connection Oriented Connection Less
Secure Insecure
3 way handshaking Doesn’t support 3 way handshaking
Slower than UDP Faster than TCP
e.g. HTTP, HTTPS, SMTP, FTP, Telnet etc. e.g. DHCP, DNS, TFTP, RIP
Client Server
3 way handshaking
SYNC
SYNC + ACK
ACK

● 32 bits address
● Format- Dotted Decimal
● No. of Addresses = 2^32 = 4.3 Billion (approx.)
To get IP Addresses
1- IANA ( Internet Assigned Number Authority )
2- RIR ( Regional Internet Registry )
3- NIR ( National Internet Registries )
4- LIR ( Local Internet Registries )
5- Local ISP( Internet Service Provider )
6- Customers
Network Addressing
Classes of IP Address and their ranges
CLASS A 1 - 126
CLASS B 128 - 191
CLASS C 192 - 223
CLASS D 224 - 239
CLASS E 240 - 255
Reserved for multicasting
Research & Development
127 – Reserved for loopback address
CLASS A : NETWORK HOST HOST HOST
CLASS B : NETWORK NETWORK HOST HOST
CLASS C : NETWORK NETWORK NETWORK HOST
8 Bits 8 Bits 8 Bits 8 Bits
In a network
First Address – Network Address
Last Address – Broadcast Address
IP ADDRESSING

Subnetting
divides a network into small networks
Benefits of subnetting :
• Reduced network traffic
• Optimized network performance
• Simplified management
• Facilitated spanning of large geographical distances
Subnet Mask only informs about the network bits out
of 32 bits address
CLASS DEFAULT SUBNET MASK
A 255.0.0.0
B 255.255.0.0
C 255.255.255.0
Default Subnet Mask Table
VLSM ( Variable Level Subnet Masking)
Public IP address – allowed in internet
Private IP address – not allowed in intrnet
Private IP Addresses
Class A : 10.0.0.0 – 10.255.255.255
Class B : 172.16.0.0 – 172.31.255.255
Class C : 192.168.0.0 – 192.168.255.255
Supernetting or Summarization
The process of taking a range of IP addresses and
advertising them in one address block
e.g. – let’s take 4 IP addresses
1. 192.168.1.1/24
2. 192.168.2.1/24
3. 192.168.3.1/24
4. 192.168.4.1/24
After Summarization we can
create a new Network as
192.168.0.0/21

CISCO ROUTER IOS
●The Cisco IOS was created to deliver network services and enable networked applications.
● Some of the important things that the Cisco router IOS software is responsible for include
– Carrying network protocols and functions
– Connecting high-speed traffic between devices
– Adding Security to control access and stop unauthorised network use
– Providing scalability for ease of network growth and redundancy
– Supplying network reliability for connecting to network resources
● Connecting to a Cisco Router
We can connect to a Cisco Router to
– configure it
– verify its configuration
– check statistics
We can connect to a Cisco Router through
– console port
– auxiliary port
Console Port
Auxiliary Port
Physical View of Router

Basic Routing Configuration
Router>enable // user mode
Router#configure terminal // privilege mode
Router(config)#hostname R1 // to change the name of Router (hostname - keyword)
R1(config)#interface f0/0 // global mode or configuration mode
R1(config-if)#ip address 192.168.1.1 255.255.255.0 // global interface mode
R1(config-if)#no shutdown
R1(config-if)#exit
R1(config)#exit
R1#write
or
R1#copy running-config startup-config
To Set PASSWORD in CONSOLE PORT / AUX PORT
R1(config)#line con 0
R1(config-line)#password abcd
R1(config-line)#login
R1(config-line)#exit
R1(config)#enable password 1234
R1(config)#enable secret 1234
To save the configuration of router
R1(config)#line aux 0
R1(config-line)#password abcd
R1(config-line)#login
R1(config-line)#exit
R1(config)#enable password 1234
R1(config)#enable secret 1234
R1(config)#service password-encryption
[hides all the plain text password and
encrypt the password]

To Create IOS BACKUP
Router#dir flash:
Directory of flash:/
3 -rw- 5571584 <no date> pt1000-i-mz.122-28.bin
2 -rw- 28282 <no date> sigdef-category.xml
1 -rw- 227537 <no date> sigdef-default.xml
64016384 bytes total (58188981 bytes free)
Router#copy flash: tftp:
Source filename []? pt1000-i-mz.122-28.bin
Address or name of remote host []? 192.168.1.2
Destination filename [pt1000-i-mz.122-28.bin]? yes
Writing pt1000-i-mz.122-28.bin....!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
[OK - 5571584 bytes]
5571584 bytes copied in 3.1 secs (411811 bytes/sec)

TO DELETE ROUTER IOS
Router#delete flash
Delete filename []?pt1000-i-mz.122-28.bin
Delete flash:/pt1000-i-mz.122-28.bin? [confirm]y
Router#reload
Proceed with reload? [confirm]y System Bootstrap, Version
12.1(3r)T2, RELEASE SOFTWARE (fc1)
Copyright (c) 2000 by cisco Systems, Inc.
RESTORING ROUTER IOS
rommon 1 > IP_ADDRESS=192.168.1.1
rommon 2 > TFTP_SERVER=192.168.1.2
rommon 3 > TFTP_FILE=pt1000-i-mz.122-28.bin
rommon 4 > IP_SUBNET_MASK=255.255.255.0
rommon 5 > DEFAULT_GATEWAY=192.168.1.2
rommon 6 > tftpdnld
IP_ADDRESS: 192.168.1.1
IP_SUBNET_MASK: 255.255.255.0
DEFAULT_GATEWAY: 192.168.1.2
TFTP_SERVER: 192.168.1.2
TFTP_FILE: pt1000-i-mz.122-28.bin
Invoke this command for disaster recovery only.
WARNING: all existing data in all partitions on flash will
be lost!
Do you wish to continue? y/n: [n]: y
rommon 7 > boot

IP ROUTING
● IP routing is the process of moving packets from one network to another network using routers.
● A routing protocol is used by routers to dynamically find all the networks in the internetwork and to ensure all
routers have same routing table. Basically, a routing protocol determines the path of a packet through an
internetwork.
e.g. RIP, IGRP, EIGRP, OSPF ROUTING
PROTOCOL
STATIC
(AD=1)
DEFAULT
(AD=254)
DYNAMIC
IGP EGP
DISTANCE VECTOR
i) RIP
ii) IGRP
LINK STATE
i) OSPF
ii) IS-IS
HYBRID
i) EIGRP
-IGP – Interior Gateway Protocol
-EGP – Exterior Gateway Protocol
● Administrative Value (AD) [range 0-255]
- shows the trustworthiness of any routing protocol
- least AD value is always preferred
● Router’s priority
1st Highest Prefix Match
2nd AD Value
3rd Metric Value
Border
Gateway
Protocol

STATIC ROUTING
Static routing is a form of routing that occurs when a router uses a manually-configured routing entry, rather than information
from a dynamic routing traffic. Static routers are manually configured by a network administrator by adding entries into routing
table.
R1(config)#int f0/0
R1(config-if)#ip address 192.168.1.1 255.255.255.0
R1(config-if)#exit
R1(config)#int s2/0
R1(config-if)#exit
R1(config)#ip route 172.16.0.0 255.255.0.0 s2/0
R1(config)#exit
R1# show ip route
R2(config)#int f0/0
R2(config-if)#exit
R2(config)#int s2/0
R2(config-if)#exit
R2(config)#ip route 192.168.1.0 255.255.255.0 s2/0
R2(config)#exit

DEFAULT ROUTING
• to make all unknown networks reachable we use default routing
• default routing suppresses the routing table
STUB ROUTER – The router who has only single exit interface point to share the traffic.
Default routing is implemented on stub router
R1 and R2 are stub routers. Default routing
will be implemented.
On R2 we will implement static routing.
For default routing
Router(config)# ip route
<unknown n/w><unknown s/m><exit int>
R1(config)# ip route 0.0.0.0 0.0.0.0 s2/0

ROUTING INFORMATION PROTOCOL ( RIP )
AD=120
Metric = hop count ( 0-15 )
Multicast address = 224.0.0.9
Algorithm = Bellman Ford
UDP Port No. 520
Hop count : when packet travels from one network to another network. ( least no of hop count is preferred )
RIP Version 1 RIP Version 2
Classful Classless
Broadcast Multicast
Broadcast address-
255.255.255.255
Multicast address-
224.0.0.9
Doesn’t support VLSM Supports VLSM
Doesn’t support summarization Supports summarization
Doesn’t support authentication Supports authentication
RIP TIMER
Update – 30 seconds
Invalid – 180 seconds
Total Down – 180 seconds
Flush out – 240 seconds
SLOW CONVERGENCE is the reason that RIP abolished from market
RIP Ver1 and Ver2 are not compatible with each other.

R1(config)#router rip
R1(config-router)#network 192.168.1.0
R1(config-router)#version 2
R1(config-router)#no auto-summary
R1(config-router)#exit
R2(config)#router rip
R3(config)#router eigrp 10
Router(config-router)# no auto-summary is used to make the protocol classless

Interior Gateway Routing Protocol (IGRP)
- Cisco proprietary routing protocol
- Works on distance vector
- Hop count =100
- AD Value = 100
Enhanced Interior Gateway Routing Protocol ( EIGRP )
- hybrid routing protocol
- Works on advance distance vector
- Hop counts = 100 (by default), can be extended upto 255
- Maintains three types of table
• Neighbor Table
• Topology Table
• Routing Table
- Sends partial update
- Fast convergence routing protocol
- Multicast address : 224.0.0.10
- Algorithm : Diffusing Update Algorithm (DUAL)
- AD Value = 90 {for internal routes}
= 170 {for external routes}
- Independent protocol, Protocol No. – 88
- Classful routing protocol (by default), can be used as classless also
- Works on AUTONOMOUS SYSTEM
Autonomous System
- A group of routers belong to a single domain
- Range : 1 to 65535
- To reduce the complexity of hop counts we
divide the networks into different autonomous
system
EIGRP can do unequal host load sharing
Matric Values
Default Values
K1 Bandwidth 1
K2 Load 0
K3 Delay 1
K4 Reliability 0
K5 MTU
(Maximum Transfer Unit)
0
Matric Calculation Formula
[10^7 / least bandwidth + sum of delay / 10] * 256

eigrp 10 ; here 10 is referred to as Autonomous System (AS) Value

Open Shortest Path First (OSPF)
• Works on link state routing protocol
• Unlimited hop counts
• Hop counts divided into areas
• Area 0 is created first and is known as backbone area or management area
• All the areas must be connected with area 0
• AD Value = 110
• Multicast Address : 224.0.0.5 (for updates / to send a hello message)
: 224.0.0.6 (for DR/BDR)
• Metric = cost (Bandwidth)
• Algorithm = SPF ( Shortest Path First)
Area Boarder Router (ABR) – to make a router ABR one of the interface must be present in AREA 0. From above diagram
R2 and R3 are Area Boarder Router (ABR).
Autonomous System Boarder Router (ASBR) – to make a router ASBR one of the interface must be present in OSPF and
another interface in different routing protocol. From above diagram
R4 is ASBR.
AREA 1
OSPF
AREA 0
OSPF
AREA 2
OSPF
AREA 3
EIGRP

AREA 0 AREA 1
R1(config)#router ospf 10
R1(config-router)#network 192.168.1.0 0.0.0.255 area 0

To make a router DR (Designated Router) and
BDR (Backup Designated Router)
1. Highest priority value is preferred. (Priority Value 0-255)
if priority value is 0, it’s neither DR nor BDR
2. Highest loopback address is preferred.
3. Highest interface IP address is preferred.
[Second Highest is preferred to make a router BDR]
- Remaining routers DRO(designated Router Others)
- DRO will form neighborship with DR and BDR
To save BANDWIDTH we use DR / BDR
Link State Advertisement ( LSA)
LSA’s 1 – Router LSA
LSA’s 2 – Network LSA
LSA’s 3 – Summary LSA
LSA’s 4 – ASBR Summary LSA
LSA’s 5 – External LSA
Wild Card Mask or Inverse Mask Table
Class A – 0.255.255.255
Class B – 0.0.255.255
Class C – 0.0.0.255

SWITCHING
Switching is the process of using the hardware address of devices on a LAN to segment a network.
- works on single broadcast domain
- With the help of VLAN (Virtual Local Area Network) broadcast domain will be divided.
- Total no. of VLAN = 4096 {range ( 0-4095 )}
- Same VLAN and same subnet mask communicate with each other
- VLAN 1’s IP address is known as management IP address
VLAN NO. DESCRIPTION
0 , 4095 Reserved for the systems
1 Cisco reserved
[default VLAN / management VLAN / Native
VLAN / Untagged VLAN ]
2 – 1001 Normal VLAN
1002 – 1005 Reserved for different technologies
1006 – 4094 Extended VLAN

SALE SALEIT IT
Case: Traffic of SALE Department shouldn’t be shared with IT Department
Put SALE Department in VLAN 10 and IT Department in VLAN 20
TRUNK : Carry the traffic of multiple VLAN
To check the status of VLAN : Switch# show vlan brief

Switch>enable
Switch#configure terminal
Switch(config)#hostname Switch1
Switch1(config)#VLAN 10
Switch1(config-vlan)#name sale
Switch1(config-vlan)#VLAN 20
Switch1(config-vlan)#name IT
Switch1(config-vlan)#exit
Switch1(config)#interface range f0/1-02
Switch1(config-if-range)#switchport mode access
Switch1(config-if-range)#switchport access VLAN 10
Switch1(config-if-range)#exit
Switch>enable
To make interface TRUNK
Switch1(config)#interface f0/5
Switch1(config-if)#switchport mode trunk

Switch>enable
Router(config)#interface f0/0
Router(config-if)#no shutdown
Router(config-if)#exit
Router(config)#int f0/0.10
Router(config-subif)#encapsulation dot1Q 10
Router(config-subif)#ip address 192.168.1.1 255.255.255.0
Router(config)#int f0/0.20
Router(config-subif)#encapsulation dot1Q 20
Router(config-subif)#ip address 10.0.0.1 255.0.0.0
Router(config-subif)#exit
192.168.1.0/24 10.0.0.0/8
INTER VLAN ROUTING
( Router on a stick )

Switch(config)#vlan 10
Switch(config-vlan)#vlan 20
Switch(config-vlan)#exit
Switch(config)#interface range f0/1-02
Switch(config-if-range)#switchport mode access
Switch(config-if-range)#switchport access vlan 10
Switch(config-if-range)#exit
Switch(config)#interface range f0/3-04
Switch(config-if-range)#switchport mode access
Switch(config-if-range)#switchport access vlan 20
Switch(config-if-range)#exit
Switch(config)#interface vlan 10
Switch(config-if)#ip address 192.168.1.1 255.255.255.0
Switch(config-if)#exit
Switch(config)#interface vlan 20
Switch(config-if)#ip address 10.0.0.1 255.0.0.0
Switch(config-if)#exit
Switch(config)#ip routing // to maintain the routing table
for switch
By default switch maintains CAM table
SWITCH VIRTUAL INTERFACE ( SVI )

Switch>enable
Switch(config)#interface f0/1 //port where security to be enabled
Switch(config-if)#switchport mode access
Switch(config-if)#switchport access vlan 1
Switch(config-if)#switchport port-security
Switch(config-if)#switchport port-security maximum 1
Switch(config-if)#switchport port-security violation shutdown
Switch(config-if)#switchport port-security mac-address FFFF.FFFF.FFFF
Switch# show port-security : to check the status of port security
Switch# show mac-address-table : to check the mac address connected to
the ports
PORT SECURITY

DYNAMIC HOST CONFIGURATION PROTOCOL ( DHCP )
Works on the concept of D O R A
• DISCOVER
- discover message generated by client
- Broadcast message sent to all, accepted by
only server, rejected by other clients due to
port no. 67
• OFFER
- Server offers IP address, gateway, DNS
server to all clients (broadcast)
- Packets are accepted and discarded with
the help of mac address
• REQUEST
- To cross check whether the same IP address
has been assigned to any other clients or
not.
- Requests for time of expiry
• ACKNOWLEDGEMENT
- From server to client if everything is okay
and allright
Automatic Private IP Address ( APIPA )
It is an error which provides IP address in
the range of
169.254.0.0 - 169.254.254.254
- DHCP is a standardized network protocol used on Internet Protocol (IP) networks for dynamically distributing network
configuration parameters.
- Computers request IP addresses and networking parameters automatically from a DHCP server
- Port No. 67 for request
- Port No. 68 for reply

Router(config)#ip dhcp pool abcd
Router(dhcp-config)#network 192.168.1.0 255.255.255.0
Router(dhcp-config)#default-router 192.168.1.1
Router(config)#ip dhcp excluded-address 192.168.1.4 192.168.1.11
(to exclude the IP addresses from pool and to provide it manually)

HOT STANDBY ROUTING PROTOCOL ( HSRP )
We use HSRP to overcome the problem of link damage of default gateway
Conditions for a router to become active
- Highest priority value [by default priority value = 100] [range 0 - 255]
- Highest interface IP address
Hello message – 3 seconds
Hold on time – 10 seconds
Router1(config)#interface f0/0
Router1(config-if)#standby 1 ip 192.168.1.254
Router1(config-if)#standby 1 priority 150
Router1(config-if)#standby 1 preempt
Router1(config-if)#exit
Router2(config)#interface f0/0
Router2(config-if)#standby 1 ip 192.168.1.254
Router2(config-if)#standby 1 priority 50
Router2(config-if)#exit
INTERNET
Is used for the automatic elections to find out the active router

ACCESS CONTROL LIST (ACL)
used for FILTERING purpose
STANDARD EXTENDED NAMING
1 – 99 100 – 199 Any name
Blocks all services or
complete protocol.
e.g. – UDP, ICMP, IGRP and
other routing protocols
Filtering can be done i.e.
few services should be
allowed and others should
be blocked
Takes decision based on
source address
Takes decision based on
both source and destination
address
Implemented near to
destination
Implemented near to source

To block a network
R2 (config)#access-list 1 deny 192.168.1.0 0.0.0.255
R2 (config)#interface f0/0
R2 (config-if)#ip access-group 1 out
To block particular IP addresses
R2(config)#access-list 5 deny host 192.168.1.2
R2(config)#access-list 5 deny host 192.168.1.3
R2(config)#access-list 5 permit any
R2(config)#int f0/0
R2(config-if)#ip access-group 5 out
Block IP address using extended
R1(config)#access-list 100 deny tcp host 192.168.1.2 host 192.168.3.5 eq 80
R1(config)#access-list 100 deny tcp host 192.168.1.2 host 192.168.3.5 eq 443
R1(config)#access-list 100 permit ip any any
R1(config)#int s2/0
R1(config-if)#ip access-group 100 out

NETWORK ADDRESS TRANSLATION ( NAT )
Types:
• Static – one private address to one public address. It’s a hard-core binding.
• Dynamic – many private addresses to many public addresses. It’s no hard-core binding
• Port Address Translation (PAT) – many private addresses to one public address
STATIC TYPE
R1(config)#ip nat inside source static 192.168.1.2 121.1.1.3
R1(config)#interface f0/0
R1(config-if)#ip nat inside
R1(config-if)#interface s2/0
R1(config-if)#ip nat outside
R1(config-if)#exit
DYNAMIC TYPE
R1(config)#access-list 1 permit host 192.168.1.2
R1(config)#access-list 1 permit host 192.168.1.3
R1(config)#ip nat inside source list 1 pool abcd
R1(config)#ip nat pool abcd 121.1.1.3 121.1.1.10 netmask 255.0.0.0
PAT
R1(config)#access-list 1 permit 192.168.1.0 0.0.0.255
R1(config)#ip nat inside source list pool abcd overload
R1(config)#ip nat pool abcd 121.1.1.3 121.1.1.3 netmask 255.0.0.0 192.168.1.0 / 24

IPv4 IPv6
32 bits 128 bits
Dotted decimal Hexadecimal
4 octant (1 octant = 8 bits) 8 field (1 field = 16 bits)
Separated by “ . ” (dot) Separated by “ : ” (colon)
Broadcast Any cast
IP Security – Not Available IP Security – Available
No. of IP Addresses = 2^32 No. of IP Addresses = 2^128
DIFFERENCE BETWEEN IPv4 and IPv6

CCNA: Introduction to Networking and Protocols

Recomendados

Recomendados

Mais conteúdo relacionado

Mais procurados

Mais procurados (20)

Semelhante a CCNA: Introduction to Networking and Protocols

Semelhante a CCNA: Introduction to Networking and Protocols (20)

Último

Último (20)

CCNA: Introduction to Networking and Protocols