WAN routing and what is LAN in CCNA

1. Fundamentals of WANs and IP
Routing
Will discuss about links used by WAN –
Ethernet and Serial Links.
TCP/IP Network Layer
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2. Wide Area Networks
• Your branch office to head office connects via WAN Link.
• WAN technology devices uses Layer 1 and Layer 2 protocol used for communication.
• Types
• Leased-line WANs
• Ethernet WANs
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3. 1.Leased-Line WANs
• WAN Links connects routers.
• Leased lines provide Layer 1
service.
1.1 Physical details of leased lines
• A company having leased lines do not own it
they have to pay other company on a
monthly basis.
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4. How Routers Use a WAN Data Link
• Routers delivers Packets.
• Routers connect a LAN and WAN link.
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5. 1. Ethernet as a WAN Technology
• Ethernet are der for more than a decade and still improving but distance of the cable matters. Ex.
• 1000BASE-LX – 5km
• 1000BASE-ZX- 70km
Key Topic : CE or CPE , PE, P ??
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6. 1.IP Routing
• Two main protocol for IP Routing or in Layer 3 are
• IPv4 – 32bit - Binary
• IPv6 – 128bit –Hexa-decimal
• IP takes care of end to end communication using a Packet.
1.1)Network Layer Routing (Forwarding) Logic
• Host operating system has TCP/IP software by default.
Host Forwarding Logic: Send the Packet to the Default Router
PC1 checks the destination address and finds that its
not in same network by doing AND between des.IP and
Source.SM
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7. Key Topic : IPv4 Address : (IANA ??)
• IPv4 address is 32 bit Binary address – Always written in decimal format.
Following image shows how its der in binary format.
128 64 32 16 8 4 2 1 128 64 32 16 8 4 2 1 128 64 32 16 8 4 2 1 128 64 32 16 8 4 2 1
x X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X
X can be either 0 or 1 as binary values has only zero’s and one’s
• Binary to Decimal conversion
128 64 32 16 8 4 2 1
X X X X X X X X
0 0 0 0 0 0 0 0
1 1 1 1 1 1 1 1
= 0
=255
** add the place value if x is 1, if zero then leave
• Total number of possible IP address is 4294967296
128 64 32 16 8 4 2 1 128 64 32 16 8 4 2 1 128 64 32 16 8 4 2 1 128 64 32 16 8 4 2 1
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1
..
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
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8. Key Topic : IP Address and classes
• Initially when internet or networking was introduced
into this world may be they all are kept under one LAN
similar to how earth evolved with humans.
• Later they thought keeping every IP in one LAN is not
good so they decided to go with Classes of IP address
Classes of IP address
Class Range of first Octet Subnet Mask
Class A 0-127 255.0.0.0
Class B 128-191 255.255.0.0
Class C 192-223 255.255.255.0
Class D 224-239 -------------------
Class E 240-255 -------------------
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9. Key Topic : Identifying which Class an IP belong to - Class A
• Class of an IP address depends on the first octet value alone.
• Octet means 8, hence it depends on first 8 bit value.
• In Class A the 32nd bit is always “Zero”
128 64 32 16 8 4 2 1 128 64 32 16 8 4 2 1 128 64 32 16 8 4 2 1 128 64 32 16 8 4 2 1
0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 0 0 0 0 0 1 0 1 0 0 0 0 0 1 1 1 1
128 64 32 16 8 4 2 1 128 64 32 16 8 4 2 1 128 64 32 16 8 4 2 1 128 64 32 16 8 4 2 1
0 1 1 1 1 1 1 1 0 0 0 0 1 0 1 0 0 0 0 0 1 0 1 0 0 0 0 0 1 1 1 1
• Quiz :
10.0.02
15.0.0.9
145.1.7.8
123.1.2.3
1.255.255.255
Remember the SM is 255.0.0.0
Means we cannot vary first 8 bits
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10. Key Topic : Class B IP address
• Class B address are used between medium to large scale
• Last 2 bits are kept “1 0” others we can vary to find out the range.
• To find minimum keep everything as 0’s result is 128
• To find maximum keep every bit as 1’s result is 192
Quiz :
129.0.0.1
178.0.0.2
146.3.4.5
221.9.8.7
128 64 32 16 8 4 2 1 128 64 32 16 8 4 2 1 128 64 32 16 8 4 2 1 128 64 32 16 8 4 2 1
1 0 0 0 0 0 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Remember the SM is 255.255.0.0
Means we cannot vary first 16 bits
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11. Key Topic : Class C IP address :
• Class C address can be used for small scale network
• First 3 bits are standard 1 1 0
• Now to find out minimum and maximum value keep all 0 and 1’s in remaining places
• Minimum Value :
• Maximum Value:
Remember the SM is 255.255.255.0
Means we cannot vary first 24 bits
128 64 32 16 8 4 2 1 128 64 32 16 8 4 2 1 128 64 32 16 8 4 2 1 128 64 32 16 8 4 2 1
1 1 0 0 0 0 1 1 0 0 0 0 0 0 0 0 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0
128 64 32 16 8 4 2 1 128 64 32 16 8 4 2 1 128 64 32 16 8 4 2 1 128 64 32 16 8 4 2 1
1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
128 64 32 16 8 4 2 1 128 64 32 16 8 4 2 1 128 64 32 16 8 4 2 1 128 64 32 16 8 4 2 1
1 1 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
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12. Key Topic : Class D and E
• To find out class D and Class E address range simply make below bits as constant
• Class D : 1 1 1 0
• Class E : 1 1 1 1
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13. Other Network Layer Feature
• Following are the very important Network Layer protocols which are in use.
1. Domain Name System (DNS)
2. Address Resolution Protocol (ARP)
3. Ping
We will see about one by one in following slides
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14. Domain Name System :
• TCP/IP defines a way to use hostnames to identify the IP address
• We can’t imagine remembering our friends phone number but we remember their names, similarly
we can’t imagine of remembering our IP address of a website.
How to find out a websites IP address (Rec 2)
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15. • Lets take an example of Bob trying to send a packet to Server 1
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16. The Address Resolution Protocol
• IP routing logic requires that hosts and routers encapsulate IP packets inside data-link layer frames.
• TCP/IP defines the Address Resolution Protocol (ARP) as the method by which any host or router on a
LAN can dynamically learn the MAC address of another IP in the same LAN
• Once it learns the MAC address it gets stored in arp cache
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17. How to view my ARP Cache
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18. ICMP Echo and the ping Command
• Primary Network tool to check IP connectivity is PING command.
• Ping (Packet Internet Groper) uses the Internet Control Message Protocol (ICMP), sending a message
called an ICMP echo request to another IP address.
• ICMP does not rely on any application.
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