© 2000, Cisco Systems, Inc. 8-1
Chapter 8Chapter 8
Interconnecting Networks with
TCP/IP
Interconnecting Networks with
TCP/IP
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-3
Upon completion of this chapter you will be able to perform the following tasks:• Identify the IP protocol stack, its protocol layer functions, and commonly used IP protocols
• Identify IP address classes, IP addresses, IP subnet masks, IP network numbers, subnet numbers, and possible host numbers.
• Configure IP addresses and subnet masks on a router interface and optionally configure a host table.
• Interconnect the VLANs with a layer three device such
as a router on a stick.
ObjectivesObjectives
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-4
Early protocol suite
Universal
Introduction to TCP/IPIntroduction to TCP/IP
Host
Internet
TCP/IP
Host
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-5
TCP/IP Protocol StackTCP/IP Protocol Stack
7
6
5
4
3
2
5
4
3
2
Application
Presentation
Session
Transport
Network
Data Link
Physical1
Application
Transport
Internet
Data Link
Physical1
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-6
Application Layer OverviewApplication Layer Overview
*Used by the router
Application
Transport
Internet
Data Link
Physical
File Transfer- TFTP *- FTP *- NFS
E-Mail- SMTP
Remote Login- Telnet *- rlogin *
Network Management- SNMP *
Name Management- DNS*
File Transfer- TFTP *- FTP *- NFS
E-Mail- SMTP
Remote Login- Telnet *- rlogin *
Network Management- SNMP *
Name Management- DNS*
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-7
Transport Layer OverviewTransport Layer Overview
Transmission ControlProtocol (TCP)
User Datagram Protocol (UDP)
Transmission ControlProtocol (TCP)
User Datagram Protocol (UDP)
Application
Transport
Internet
Data Link
Physical
Connection-Oriented
Connectionless
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-8
TCP Segment FormatTCP Segment Format
Source port (16) Destination port (16)
Sequence number (32)
Headerlength (4)
Acknowledgement number (32)
Reserved (6) Code bits (6) Window (16)
Checksum (16) Urgent (16)
Options (0 or 32 if any)
Data (varies)
20Bytes
Bit 0 Bit 15 Bit 16 Bit 31
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-9
Port NumbersPort Numbers
TCP
Port Numbers
FTP
TransportLayer
TELNET
DNS
SNMP
TFTP
SMTP
UDP
ApplicationLayer
2121 2323 2525 5353 6969 161161
RIP
520520
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-10
TCP Port NumbersTCP Port Numbers
SourcePort
SourcePort
Dest.Port
Dest.Port ……
Host A
10281028 2323 ……
SP DP
Host ZTelnet Z
Dest. port = 23.Send packet to my
Telnet application.
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-11
Send SYN (seq=100 ctl=SYN)
SYN received
Host A Host B
TCP Three Way Handshake/Open Connection
TCP Three Way Handshake/Open Connection
1
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-12
Send SYN (seq=100 ctl=SYN)
SYN received
Send SYN, ACK (seq=300 ack=101 ctl=syn,ack)
Host A Host B
SYN received
1
2
TCP Three Way Handshake/Open Connection
TCP Three Way Handshake/Open Connection
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-13
Send SYN (seq=100 ctl=SYN)
SYN received
Send SYN, ACK (seq=300 ack=101 ctl=syn,ack)
Established(seq=101 ack=301 ctl=ack)
Host A Host B
1
2
3
SYN received
TCP Three Way Handshake/Open Connection
TCP Three Way Handshake/Open Connection
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-14
TCP Simple AcknowledgmentTCP Simple Acknowledgment
Window size = 1
Sender Receiver
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-15
TCP Simple AcknowledgmentTCP Simple Acknowledgment
Window size = 1
Sender Receiver
Send 1Receive 1
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-16
TCP Simple AcknowledgmentTCP Simple Acknowledgment
Window size = 1
Sender Receiver
Send 1Receive 1
Receive ACK 2 Send ACK 2
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-17
TCP Simple AcknowledgmentTCP Simple Acknowledgment
Window size = 1
Sender Receiver
Send 1Receive 1
Receive ACK 2 Send ACK 2
Send 2Receive 2
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-18
TCP Simple AcknowledgmentTCP Simple Acknowledgment
Window size = 1
Sender Receiver
Send 1Receive 1
Receive ACK 2 Send ACK 2
Send 2Receive 2
Receive ACK 3Send ACK 3
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-19
TCP Simple AcknowledgmentTCP Simple Acknowledgment
Window size = 1
Sender Receiver
Send 1Receive 1
Receive ACK 2 Send ACK 2
Send 2Receive 2
Receive ACK 3Send ACK 3
Send 3Receive 3
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-20
Window size = 1
Sender Receiver
Send 1Receive 1
Receive ACK 2 Send ACK 2
Send 2Receive 2
Receive ACK 3Send ACK 3
Send 3Receive 3
Receive ACK 4 Send ACK 4
TCP Simple AcknowledgmentTCP Simple Acknowledgment
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-21
TCP Sequence and Acknowledgment Numbers
TCP Sequence and Acknowledgment Numbers
SourcePort
SourcePort
Dest.Port
Dest.Port
……Sequence#
Sequence#
Acknowledgement#
Acknowledgement#
Source Dest. Seq. Ack.
1028 23 10 1
I justsent #10.
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-22
TCP Sequence and Acknowledgment Numbers
I just got #10,now I need #11.
SourcePort
SourcePort
Dest.Port
Dest.Port ……
Sequence#
Sequence#
Acknowledgement#
Acknowledgement#
10281028 2323
Source Dest.
10101010
Seq.
11
Ack.
102810282323
Source Dest.
11111111
Seq.
11
Ack.
I justsent #10.
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-23
TCP Sequence and Acknowledgment Numbers
TCP Sequence and Acknowledgment Numbers
SourcePort
SourcePort
Dest.Port
Dest.Port ……
Sequence#
Sequence#
Acknowledgement#
Acknowledgement#
10281028 2323
Source Dest.
11111111
Seq.
22
Ack.
10281028 2323
Source Dest.
10101010
Seq.
11
Ack.
102810282323
Source Dest.
11111111
Seq.
11
Ack.
I just got #10,now I need #11.
I justsent #11.
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-24
TCP Sequence and Acknowledgment Numbers
TCP Sequence and Acknowledgment Numbers
SourcePort
SourcePort
Dest.Port
Dest.Port ……
Sequence#
Sequence#
Acknowledgement#
Acknowledgement#
10281028 2323
Source Dest.
11111111
Seq.
101101
Ack.
10281028 2323
Source Dest.
10101010
Seq.
100100
Ack.
102810282323
Source Dest.
11111111
Seq.
100100
Ack.
102810282323
Source Dest.
12121212
Seq.
101101
Ack.
I just got #11,now I need #12.
I justsent #11.
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-25
TCP WindowingTCP Windowing
Sender Receiver
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-26
TCP WindowingTCP Windowing
Window size = 3Send 2
Sender ReceiverWindow size = 3Send 1
Window size = 3Send 3
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-27
Window size = 3Send 2
TCP WindowingTCP Windowing
Sender Window size = 3Send 1
Window size = 3Send 3
ACK 3Window size = 2
Packet 3 isDropped
Receiver
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-28
Window size = 3Send 2
TCP WindowingTCP Windowing
Sender Window size = 3Send 1
Window size = 3Send 3
ACK 3Window size = 2
Packet 3 isDropped
Window size = 3Send 4
Window size = 3Send 3
Receiver
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-29
Window size = 3Send 2
TCP WindowingTCP Windowing
Sender Window size = 3Send 1
Window size = 3Send 3
ACK 3Window size = 2
Packet 3 isDropped
Window size = 3Send 4
Window size = 3Send 3
ACK 5Window size = 2
ReceiverWindow size = 3
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-30
No sequence or acknowledgment fields
UDP Segment FormatUDP Segment Format
Source port (16) Destination port (16)
Length (16)
Data (if any)
1Bit 0 Bit 15 Bit 16 Bit 31
Checksum (16)
8Bytes
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-31
Internet Layer OverviewInternet Layer Overview
OSI network layer corresponds to the TCP/IP internet layer
Internet Protocol (IP)
Internet Control MessageProtocol (ICMP)
Address ResolutionProtocol (ARP)
Reverse AddressResolution Protocol (RARP)
Internet Protocol (IP)
Internet Control MessageProtocol (ICMP)
Address ResolutionProtocol (ARP)
Reverse AddressResolution Protocol (RARP)
Application
Transport
Internet
Data Link
Physical
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-32
IP DatagramIP Datagram
Version(4)
Destination IP Address (32)
Options (0 or 32 if any)
Data (varies if any)
1Bit 0 Bit 15 Bit 16 Bit 31
HeaderLength (4)
Priority & Type of Service (8) Total Length (16)
Identification (16)Flags
(3) Fragment offset (13)
Time to live (8) Protocol (8) Header checksum (16)
Source IP Address (32)
20Bytes
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-33
Determines destination upper-layer protocol
Protocol FieldProtocol Field
TransportLayer
InternetLayer
TCP UDP
ProtocolNumbers
IP
176
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-34
Internet Control Message Protocol
Internet Control Message Protocol
Application
Transport
Internet
Data Link
Physical
Destination Unreachable
Echo (Ping)
Other
ICMP1
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-35
Address Resolution ProtocolAddress Resolution Protocol
172.16.3.1 172.16.3.2
IP: 172.16.3.2 = ???IP: 172.16.3.2 = ???
I need the Ethernet address of 176.16.3.2.
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-36
Address Resolution ProtocolAddress Resolution Protocol
172.16.3.1 172.16.3.2
IP: 172.16.3.2 = ???IP: 172.16.3.2 = ???
I heard that broadcast. The message is for me. Here is my Ethernet address.
I need the Ethernet address of 176.16.3.2.
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-37
Address Resolution ProtocolAddress Resolution Protocol
172.16.3.1
IP: 172.16.3.2 Ethernet: 0800.0020.1111 IP: 172.16.3.2 Ethernet: 0800.0020.1111
172.16.3.2
IP: 172.16.3.2 = ???IP: 172.16.3.2 = ???
I heard that broadcast. The message is for me. Here is my Ethernet address.
I need the Ethernet address of 176.16.3.2.
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-38
Address Resolution ProtocolAddress Resolution Protocol
Map IP MAC
Local ARP
172.16.3.1
IP: 172.16.3.2 Ethernet: 0800.0020.1111 IP: 172.16.3.2 Ethernet: 0800.0020.1111
172.16.3.2
IP: 172.16.3.2 = ???IP: 172.16.3.2 = ???
I heard that broadcast. The message is for me. Here is my Ethernet address.
I need the Ethernet address of 176.16.3.2.
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-39
Reverse ARPReverse ARP
Ethernet: 0800.0020.1111 IP = ???Ethernet: 0800.0020.1111 IP = ???
What is my IP address?
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-40
Reverse ARPReverse ARP
Ethernet: 0800.0020.1111 IP = ???Ethernet: 0800.0020.1111 IP = ???
What is my IP address?
I heard that broadcast. Your IP address is 172.16.3.25.
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-41
Reverse ARPReverse ARP
Ethernet: 0800.0020.1111IP: 172.16.3.25
Ethernet: 0800.0020.1111IP: 172.16.3.25
Ethernet: 0800.0020.1111 IP = ???Ethernet: 0800.0020.1111 IP = ???
What is my IP address?
I heard that broadcast. Your IP address is 172.16.3.25.
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-42
Reverse ARPReverse ARP
Map MAC IP
Ethernet: 0800.0020.1111IP: 172.16.3.25
Ethernet: 0800.0020.1111IP: 172.16.3.25
Ethernet: 0800.0020.1111 IP = ???Ethernet: 0800.0020.1111 IP = ???
What is my IP address?
I heard that broadcast. Your IP address is 172.16.3.25.
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-43
• Unique addressing allows communication between end stations
• Path choice is based on destination addressLocation is represented by an address
Introduction to TCP/IP Addresses
Introduction to TCP/IP Addresses
172.18.0.2
172.18.0.1
172.17.0.2172.17.0.1
172.16.0.2
172.16.0.1
SADAHDR DATA10.13.0.0 192.168.1.0
10.13.0.1 192.168.1.1
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-44
IP Addressing
255 255 255 255
DottedDecimal
Maximum
Network Host
32 bits
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-45
IP AddressingIP Addressing
255 255 255 255
DottedDecimal
Maximum
Network Host
128 64 32 16 8 4 2 1
11111111 11111111 11111111 11111111Binary
32 bits
1 8 9 16 17 24 25 32
128 64 32 16 8 4 2 1
128 64 32 16 8 4 2 1
128 64 32 16 8 4 2 1
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-46
IP AddressingIP Addressing
255 255 255 255
DottedDecimal
Maximum
Network Host
128 64 32 16 8 4 2 1
11111111 11111111 11111111 11111111
10101100 00010000 01111010 11001100
Binary
32 bits
172 16 122 204ExampleDecimal
ExampleBinary
1 8 9 16 17 24 25 32
128 64 32 16 8 4 2 1
128 64 32 16 8 4 2 1
128 64 32 16 8 4 2 1
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-47
Class A:
Class B:
Class C:
Class D: Multicast
Class E: Research
IP Address ClassesIP Address Classes
NetworkNetwork HostHost HostHost HostHost
NetworkNetwork NetworkNetwork HostHost HostHost
NetworkNetwork NetworkNetwork NetworkNetwork HostHost
8 bits 8 bits 8 bits 8 bits
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-48
IP Address ClassesIP Address Classes
1
Class A:
Bits:
0NNNNNNN0NNNNNNN HostHost HostHost HostHost
8 9 16 17 24 25 32
Range (1-126)
1
Class B:
Bits:
10NNNNNN10NNNNNN NetworkNetwork HostHost HostHost
8 9 16 17 24 25 32
Range (128-191)1
Class C:
Bits:
110NNNNN110NNNNN NetworkNetwork NetworkNetwork HostHost
8 9 16 17 24 25 32
Range (192-223)1
Class D:
Bits:
1110MMMM1110MMMM Multicast GroupMulticast Group Multicast GroupMulticast Group Multicast GroupMulticast Group
8 9 16 17 2425 32
Range (224-239)
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-49
Host AddressesHost Addresses
172.16.2.2
172.16.3.10
172.16.12.12
10.1.1.1
10.250.8.11
10.180.30.118
E1
172.16 12 12
Network Host
. . Network Interface
172.16.0.0
10.0.0.0
E0
E1
Routing Table
172.16.2.1
10.6.24.2
E0
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-50
11111111
Determining Available Host Addresses
Determining Available Host Addresses
172 16 0 0
10101100 00010000 00000000 00000000
16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1
Network Host
00000000 00000001
11111111 11111111 11111111 11111110
...
... 00000000 00000011
11111101
123
655346553565536-
...
2
65534
N
2N-2 = 216-2 = 65534
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-51
IP Address Classes ExerciseIP Address Classes Exercise
Address Class Network Host
10.2.1.1
128.63.2.100
201.222.5.64
192.6.141.2
130.113.64.16
256.241.201.10
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-52
IP Address Classes Exercise Answers
IP Address Classes Exercise Answers
Address Class Network Host
10.2.1.1
128.63.2.100
201.222.5.64
192.6.141.2
130.113.64.16
256.241.201.10
A
B
C
C
B
Nonexistent
10.0.0.0
128.63.0.0
201.222.5.0
192.6.141.0
130.113.0.0
0.2.1.1
0.0.2.100
0.0.0.64
0.0.0.2
0.0.64.16
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-53
Network 172.16.0.0
172.16.0.0
Addressing without SubnetsAddressing without Subnets
172.16.0.1 172.16.0.2 172.16.0.3
…...
172.16.255.253 172.16.255.254
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-54
Network 172.16.0.0
Addressing with SubnetsAddressing with Subnets
172.16.1.0 172.16.2.0
172.16.3.0
172.16.4.0
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-55
Subnet AddressingSubnet Addressing
172.16.2.200
172.16.2.2
172.16.2.160
172.16.2.1
172.16.3.5
172.16.3.100
172.16.3.150
E0
172.16
Network
Network Interface
172.16.0.0
172.16.0.0
E0
E1
New Routing Table
2 160
Host
. .
172.16.3.1E1
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-56
Subnet AddressingSubnet Addressing
172.16.2.200
172.16.2.2
172.16.2.160
172.16.2.1
172.16.3.5
172.16.3.100
172.16.3.150
172.16.3.1
E0E1
172.16 2 160
Network Host
. . Network Interface
172.16.2.0
172.16.3.0
E0
E1
New Routing Table
Subnet
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-57
Subnet MaskSubnet Mask
172172 1616 00 00
255255 255255 00 00
255255 255255 255255 00
IPAddress
DefaultSubnet
Mask
8-bitSubnet
Mask
Network Host
Network Host
Network Subnet Host
Also written as “/16” where 16 represents the number of 1s in the mask.
Also written as “/24” where 24 represents the number of 1s in the mask.
11111111 11111111 00000000 00000000
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-58
Decimal Equivalents of Bit Patterns
Decimal Equivalents of Bit Patterns
0 0 0 0 0 0 0 0 = 0
1 0 0 0 0 0 0 0 = 128
1 1 0 0 0 0 0 0 = 192
1 1 1 0 0 0 0 0 = 224
1 1 1 1 0 0 0 0 = 240
1 1 1 1 1 0 0 0 = 248
1 1 1 1 1 1 0 0 = 252
1 1 1 1 1 1 1 0 = 254
1 1 1 1 1 1 1 1 = 255
128 64 32 16 8 4 2 1
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-59
16
Network Host
172 0 0
10101100
11111111
10101100
00010000
11111111
00010000
00000000
00000000
10100000
00000000
00000000
Subnets not in use—the default
00000010
Subnet Mask without SubnetsSubnet Mask without Subnets
172.16.2.160172.16.2.160
255.255.0.0 255.255.0.0
NetworkNumber
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-60
Network number extended by eight bits
Subnet Mask with SubnetsSubnet Mask with Subnets
16
Network Host
172.16.2.160172.16.2.160
255.255.255.0 255.255.255.0
172 2 0
10101100
11111111
10101100
00010000
11111111
00010000
11111111
00000010
10100000
00000000
00000000
00000010
Subnet
NetworkNumber
128
192
224
240
248
252
254
255
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-61
Subnet Mask with Subnets (cont.)
Subnet Mask with Subnets (cont.)
Network Host
172.16.2.160172.16.2.160
255.255.255.192 255.255.255.192
10101100
11111111
10101100
00010000
11111111
00010000
11111111
00000010
10100000
11000000
10000000
00000010
Subnet
Network number extended by ten bits
16172 2 128
NetworkNumber
128
192
224
240
248
252
254
255
128
192
224
240
248
252
254
255
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-62
Subnet Mask ExerciseSubnet Mask Exercise
Address Subnet Mask Class Subnet
172.16.2.10
10.6.24.20
10.30.36.12
255.255.255.0
255.255.240.0
255.255.255.0
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-63
Subnet Mask Exercise Answers
Subnet Mask Exercise Answers
Address Subnet Mask Class Subnet
172.16.2.10
10.6.24.20
10.30.36.12
255.255.255.0
255.255.240.0
255.255.255.0
B
A
A
172.16.2.0
10.6.16.0
10.30.36.0
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-64
Broadcast AddressesBroadcast Addresses
172.16.1.0
172.16.2.0
172.16.3.0
172.16.4.0
172.16.3.255(Directed broadcast)
255.255.255.255(Local network broadcast)
XX
172.16.255.255(All subnets broadcast)
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-65
Addressing Summary Example
Addressing Summary Example
16172 2 160
10101100 00010000 1010000000000010 Host
Mask
Subnet
Broadcast
Last
First
172.16.2.160
255.255.255.192
4
1
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-66
Addressing Summary Example
Addressing Summary Example
10101100
11111111
00010000
11111111 11111111
10100000
11000000
00000010 Host
Mask
Subnet
Broadcast
Last
First
172.16.2.160
255.255.255.192
1
2
16172 2 160
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-67
Addressing Summary Example
Addressing Summary Example
10101100
11111111
00010000
11111111 11111111
10100000
11000000
00000010 Host
Mask
Subnet
Broadcast
Last
First
172.16.2.160
255.255.255.192
1
2
3
7
16172 2 160
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-68
Addressing Summary Example
Addressing Summary Example
10101100
11111111
00010000
11111111 11111111
10100000
11000000
10000000
00000010 Host
Mask
Subnet
Broadcast
Last
First
172.16.2.160
255.255.255.192
1
2
3
4
16172 2 160
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-69
Addressing Summary Example
Addressing Summary Example
10101100
11111111
00010000
11111111 11111111
10100000
11000000
10000000
00000010
10111111
Host
Mask
Subnet
Broadcast
Last
First
172.16.2.160
255.255.255.192
1
2
3
4
56
16172 2 160
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-70
Addressing Summary Example
Addressing Summary Example
10101100
11111111
00010000
11111111 11111111
10100000
11000000
10000000
00000010
10111111
10000001
Host
Mask
Subnet
Broadcast
Last
First
172.16.2.160
255.255.255.192
1
2
3
4
56
16172 2 160
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-71
Addressing Summary Example
Addressing Summary Example
10101100
11111111
00010000
11111111 11111111
10100000
11000000
10000000
00000010
10111111
10000001
10111110
Host
Mask
Subnet
Broadcast
Last
First
172.16.2.160
255.255.255.192
1
2
3
4
56
7
16172 2 160
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-72
Addressing Summary Example
Addressing Summary Example
10101100
11111111
10101100
00010000
11111111
00010000
11111111
00000010
10100000
11000000
10000000
00000010
10101100 00010000 00000010 10111111
10101100 00010000 00000010 10000001
10101100 00010000 00000010 10111110
Host
Mask
Subnet
Broadcast
Last
First
172.16.2.160
255.255.255.192
1
2
3
4
56
7
8
16172 2 160
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-73
Addressing Summary Example
Addressing Summary Example
10101100
11111111
10101100
00010000
11111111
00010000
11111111
00000010
10100000
11000000
10000000
00000010
10101100 00010000 00000010 10111111
10101100 00010000 00000010 10000001
10101100 00010000 00000010 10111110
Host
Mask
Subnet
Broadcast
Last
First
172.16.2.160
255.255.255.192
172.16.2.128
172.16.2.191
172.16.2.129
172.16.2.190
1
2
3
4
56
7
89
16172 2 160
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-74
IP Host Address: 172.16.2.121Subnet Mask: 255.255.255.0
Subnet Address = 172.16.2.0Host Addresses = 172.16.2.1–172.16.2.254Broadcast Address = 172.16.2.255Eight bits of subnetting
Network Subnet Host
10101100 00010000 00000010 11111111
172.16.2.121:
255.255.255.0:
10101100
11111111
Subnet: 10101100 00010000
00010000
11111111
00000010
00000010
11111111
01111001
00000000
00000000
Class B Subnet ExampleClass B Subnet Example
Broadcast:
Network
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-75
Subnet PlanningSubnet Planning
Other subnets
192.168.5.16
192.168.5.32 192.168.5.48
20 subnets
5 hosts per subnet
Class C address:
192.168.5.0
20 subnets
5 hosts per subnet
Class C address:
192.168.5.0
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-76
11111000
IP Host Address: 192.168.5.121Subnet Mask: 255.255.255.248
Network Subnet Host
192.168.5.121: 11000000
11111111
Subnet: 11000000 10101000
10101000
11111111
00000101
00000101
11111111
01111001
01111000
255.255.255.248:
Class C Subnet Planning Example
Class C Subnet Planning Example
Subnet Address = 192.168.5.120Host Addresses = 192.168.5.121–192.168.5.126Broadcast Address = 192.168.5.127Five Bits of Subnetting
Broadcast:
NetworkNetwork
11000000 10101000 00000101 01111111
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-77
Broadcast Addresses ExerciseBroadcast Addresses Exercise
Address Class Subnet Broadcast
201.222.10.60 255.255.255.248
Subnet Mask
15.16.193.6 255.255.248.0
128.16.32.13 255.255.255.252
153.50.6.27 255.255.255.128
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-78
Broadcast Addresses Exercise Answers
Broadcast Addresses Exercise Answers
153.50.6.127
Address Class Subnet Broadcast
201.222.10.60 255.255.255.248 C 201.222.10.63201.222.10.56
Subnet Mask
15.16.193.6 255.255.248.0 A 15.16.199.25515.16.192.0
128.16.32.13 255.255.255.252 B 128.16.32.15128.16.32.12
153.50.6.27 255.255.255.128 B 153.50.6.0
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-79
Switch IP Address Configuration
Switch IP Address Configuration
• Assigns an address and subnet mask• Starts IP processing on a switch
Switch(config)#ip address ip-address subnet-maskSwitch(config)#ip address ip-address subnet-mask
Switch(config)#ip default-gateway ip-addressSwitch(config)#ip default-gateway ip-address
• Specifies a default gateway
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-80
Router IP Address Configuration
Router IP Address Configuration
• Assigns an address and subnet mask• Starts IP processing on a router interface
Router(config-if)#ip address ip-address subnet-maskRouter(config-if)#ip address ip-address subnet-mask
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-81
Router IP Address Configuration
Router IP Address Configuration
Router(config-line)#ip netmask-format {bitcount | decimal | hexadecimal} Router(config-line)#ip netmask-format {bitcount | decimal | hexadecimal}
• Sets format of network mask for a specific line
Router#term ip netmask-format {bitcount| decimal | hexadecimal} Router#term ip netmask-format {bitcount| decimal | hexadecimal}
• Sets display format of network mask forcurrent session
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-82
• Defines static host name to IP address mapping
• Hosts/interfaces selectable by name or IP address
Router IP Host NamesRouter IP Host Names
Router(config)#ip host name [tcp-port-number]address [address]Router(config)#ip host name [tcp-port-number]address [address]
ip host Norine 172.16.3.1 192.168.3.1ip host Roger 172.16.4.3ip host Norine 172.16.3.1 192.168.3.1ip host Roger 172.16.4.3
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-83
• Specifies one or more hosts that supplyhost name to logical address resolution
Router Name Server Configuration
Router Name Server Configuration
Router(config)#ip name-server server-address1 [[server-address2]...[server-address6]]Router(config)#ip name-server server-address1 [[server-address2]...[server-address6]]
DNS Server
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-84
• DNS enabled by default
Router Name SystemRouter Name System
Router(config)#ip domain-lookupRouter(config)#endRouter#patTranslating ”pat"...domain server (255.255.255.255)% Unknown command or computer name, or unable to find computer addressRouter#config tRouter(config)#no ip domain-lookupRouter(config)#endRouter#patTranslating ”pat"% Unknown command or computer name, or unable to find computer addressRouter#
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-85
Router Display Host NamesRouter Display Host Names
Router#show hostsDefault domain is not setName/address lookup uses domain serviceName servers are 255.255.255.255
Host Flags Age Type Address(es)Norine (perm, OK) 0 IP 172.16.100.100Roger (perm, OK) 0 IP 172.16.100.101Frank (perm, OK) 0 IP 172.16.200.200Bob (perm, OK) 0 IP 172.16.200.201
• Shows the host table
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-86
VLAN to VLAN OverviewVLAN to VLAN Overview
VLAN 1 VLAN 2
ISL
10.1.1.2 10.2.2.2
Network layer devices combine multiple broadcast domains
Router on a stick
Application
TCPIP
ISLEthernet
Fa0/0
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-87
Dividing a Physical Interface into Subinterfaces
Dividing a Physical Interface into Subinterfaces
FastEthernet 0/0
FastEthernet 0/0.2FastEthernet 0/0.3
FastEthernet 0/0.1
Physical interfaces can be divided into multiple subinterfaces
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-88
ISL EncapsulationISL Encapsulation
• Enables ISL on a subinterface
Router(config-subif)#encapsulation isl vlan identifierRouter(config-subif)#encapsulation isl vlan identifier
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-89
Routing Between VLANsRouting Between VLANs
VLAN 1 VLAN 2
ISL
interface fastethernet 0/0 no ip address!interface fastethernet 0/0.1 ip address 10.1.1.1 255.255.255.0 encapsulation isl 1interface fastethernet 0/0.2 ip address 10.2.2.1 255.255.255.0 encapsulation isl 2
FastE0/0
10.1.1.2 10.2.2.2
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-90
Routing Between WANsRouting Between WANs
ISL
interface Serial0 ip address 172.16.1.1 255.255.255.0
Application
TCPIP
HDLCSerial
S0
172.16.1.1172.16.1.2
VLAN 1 VLAN 2
10.1.1.2 10.2.2.2
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-91
Visual ObjectiveVisual Objective
core_ server
wg_sw_a10.1.1.10
wg_sw_l10.1.1.120
...
e0/1fa0/26(port A)
e0/1fa0/26(port A)
fa0/1 fa0/12
fa0/24
core_sw_a10.1.1.2
core_sw_b10.1.1.4
fa0/12 fa0/1
fa0/13 fa0/13
fa0/27(port B)
fa0/27(port B)
wg_pc_a10.2.2.12
wg_pc_l10.13.13.12
Core_ro
fa0/23
fa0/0
fa0/14fa0/14
VLAN2
VLAN13
SUBNET VLAN POD10.1.1.0 1 wg_ro_x, wg_sw_x, core_sw_a, core_sw_b10.2.2.0 2 wg_pc_a, core_server, core_ro10.3.3.0 3 wg_pc_b, core_server, core_ro10.4.4.0 4 wg_pc_c, core_server, core_ro10.5.5.0 5 wg_pc_d, core_server, core_ro10.6.6.0 6 wg_pc_e, core_server, core_ro10.7.7.0 7 wg_pc_f, core_server, core_ro10.8.8.0 8 wg_pc_g, core_server, core_ro10.9.9.0 9 wg_pc_h, core_server, core_ro10.10.10.0 10 wg_pc_i, core_server, core_ro10.11.11.0 11 wg_pc_j, core_server, core_ro10.12.12.0 12 wg_pc_k, core_server, core_ro10.13.13.0 13 wg_pc_l, core_server, core_ro
SUBNET VLAN POD10.1.1.0 1 wg_ro_x, wg_sw_x, core_sw_a, core_sw_b10.2.2.0 2 wg_pc_a, core_server, core_ro10.3.3.0 3 wg_pc_b, core_server, core_ro10.4.4.0 4 wg_pc_c, core_server, core_ro10.5.5.0 5 wg_pc_d, core_server, core_ro10.6.6.0 6 wg_pc_e, core_server, core_ro10.7.7.0 7 wg_pc_f, core_server, core_ro10.8.8.0 8 wg_pc_g, core_server, core_ro10.9.9.0 9 wg_pc_h, core_server, core_ro10.10.10.0 10 wg_pc_i, core_server, core_ro10.11.11.0 11 wg_pc_j, core_server, core_ro10.12.12.0 12 wg_pc_k, core_server, core_ro10.13.13.0 13 wg_pc_l, core_server, core_ro
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-92
SummarySummary
After completing this chapter, you should be able to perform the following tasks:• Identify the TCP/IP protocol stack and the functions
of each layer
• Separate an IP address into its subcomponents: the network, subnet, and host portions
• Configure IP addresses on Cisco router and switch interfaces
• Interconnect VLANs using a layer three device such as a “router on a stick”
© 2000, Cisco Systems, Inc. www.cisco.com ICND v1.0a—8-93
Review QuestionsReview Questions
1. What is the difference between the TCP and UDP transport layer protocols?
2. Given a host with IP address, 192.168.20.1 255.255.255.240, how many other hosts can you have in that network?
3. What is required to interconnect separate VLANs?