NETWORK ESSENTIALS
1.
Introduction
2.
Cables, Connectors
3.
Standards – Ethernet – Token Ring –
FDDI
4.
OSI Reference Model
5.
Types of Service
II.
TCP/IP Basics
III.
TCP/IP Addressing and Subnetting
IV.
CISCO Router Hardware Basics
V.
CISCO Router IOS Basics
VI.
CISCO Router IOS Management
VII.
ROUTING
VIII. WAN Technologies
IX.
ACCESS LIST
X.
SWITCH Basics
XI.
VLAN Concepts and Configuration
XII. INTER-VLAN Concepts
XIII.
VTP/STP
Concepts
XIV.
NAT
NETWORK ESSENTIALS
Types of Network
1.
LAN
2.
WAN
3.
INTERNET
Types of LAN
1.
Client/Server
2.
Peer to Peer
Network Components
1.
Network Hardware
2.
Network Software
Network Hardware
1.
Network Interface Card ( NIC )
2.
Transmission Media
3.
Two or more Computers
4.
Network Devices
Network Software
1.
Network Operating System ( NOS)
Transmission Media
1.
Twisted Pair Cable
2.
Coaxial Cable
3.
Fiber Optic Cable
4.
Wireless LAN
TIA Standard (Telecommunication Information Association)
Twisted Pair Cable
1.
Unshielded twisted pair ( UTP)
2.
Shielded twisted pair ( STP)
UTP categories
a. CAT 1 used for telephone (1 pair)
b. CAT 2 4 MbPS for token ring (2 pairs)
c. CAT 3 10 MbPS for Ethernet (4 pairs)
d. CAT 4 16 MbPS for Fast Token Ring (4 pairs)
e. CAT 5 100 MbPS for Fast Ethernet (4 pairs)
e. CAT 5e 1 GbPS for Gigabit Ethernet
f. CAT 6 1 Gbps for Multi Gigabit
CABLE
SPECIFICATIONS
Gigabit 1000
BASE T 1000MbPS
Fast 10
BASE T 10 MbPS Baseband
Twisted Pair (100 mts)
Ethernet 100
BASE T 100 MbPS Baseband Twisted Pair (100 mts)
100
BASE TX 100 MbPS Baseband (220 mts)
Connector RJ 45
STP Connector
RJ 45, RJ 11, RS- 232, RS -449
155 MbPS
Connections
1.
STRAIGHT THROUGH ( T568A – T568 A )
2.
CROSS OVER ( T568A – T568 B)
STRAIGHT THROUGH
T 568 A T 568 A
1. Green White
(TX +) Green
White
2. Green (TX-) Green
3. Orange White
(RX +) Orange White
4. Blue Blue
5. Blue White Blue
White
6. Orange (RX-) Orange
7. Brown White Brown
White
8. Brown Brown
[1-3, 2-6 ]
CROSS OVER
T 568A T 568 B
1. Green White
[TX +] Orange White
2. Green [TX
-] Orange
3. Orange White
[RX +] Green
White
4. Blue Blue
5. Blue White Blue
White
6. Orange [RX -] Green
7. Brown White Brown
White
8. Brown Brown
COAXIAL CABLE [RG
/68]
1.
THIN NET [ 0.25 “]
2.
THICK NET [0.4 “]
CABLE
SPECIFICATION
10 Base 2 Thin
net 200
mts [6 mm]
10 Base 5 Thick
net 500 mts [13 mm]
Connectors
BNC [BAYONET- NEILL-CONCELMAN]
It includes T-connector
Parallel connector
Terminator
VAM PIRE TAP Standard
Ethernet [thick net]
BNC Thin
Ethernet
FIBER OPTIC
SPECIFICATION
1000 Base LX Long wavelength,
Multimode [3 km] or Single Mode [100 km]
1000 Base SX Short
wavelength,
10 Base F 2000
mts
FIBER OPTIC
Multi Mode used
LED used in LAN’s
Single Mode used
LASER used in telephone network
Connectors
* SC
* ST
NETWORK TECHNOLOGIES
1.
ETHERNET
2.
TOKEN RING
3.
FDDI [Fiber Distributed Data Interface ]
ETHERNET
- 10 MbPS
- Revisions
- Fast Ethernet [ IEEE 802.3U ] 100 MbPS
- Gigabit Ethernet [ IEEE 802.5 ] 100 MbPS or 1 GbPS
CSMA/CD [Carrier Sense Multiple
Access / Collision Detection]
- Ethernet` at Data Link layer is responsible for Ethernet addressing, commonly referred to as hardware addressing or MAC addressing
- Ethernet is also responsible for framing packets received from the network layer and preparing them for transmission on the local network through Ethernet CONTENTION Media Access Method
ETHERNET FRAME
FORMAT IEEE 802.3
PRE
|
SFD
|
DA
|
SA
|
LENGTH/TYPE
|
DATA/PAD
|
FCS
|
PRE – Preamble –
7 bytes in alternating 1’s, 0’s – indicating the receiver stations that frame
is coming
SFD – Start Frame
Delimiter / synch – 1 byte
1,0,1,0,1,0,10,1 1,1,1,1,1,1,1,1
Alternations all
1’s
1, 0
- PRE uses either SFD or synch
DA – Destination
Address – 6 bytes
LSB is 0 – Individual
Address
1 – Group Address
TOKEN RING [IEEE
802.5]
- No collisions
- Ideal for applications [factory automation]
- 4 or 16 MbPS
Logically a ring but physically a star configuration to MAU
relays
- Token ring LANs continuously pass a token or a Token Ring frame
- MAU [ Outstation Access Unit]
FDDI [Fiber Distributed Data Interface]
- 100 MbPS Token passing network
- Fiber optic cable with mass length of 2 km
- Dual-ring architecture for redundancy
- Used for corporate and carrier backbones
CDDI [Copper
Distributed Data Interface]
- implements FDDI over STP and UTP cable
Dual Ring Architecture
- Primary ring for data transmissions
- Secondary ring for reliability and robustness
Components
- Single attachment station ( SAS ) for PC’s
- Dual attachment stations ( DAS ) for servers
- Concentrator
FDDI concentrator
- also called as Dual- attached concentrator (DAC)
- Building block of an FDDI network
- Attaches directly to both rings and ensures that any SAS failure or power-down does not bring down the ring
NETWORK TOPOLOGIES
Defines Network Device Organization
Four common types
- BUS Topology
- TREE Topology
- STAR Topology
- RING Topology
Topologies are logical Architecture
Actual devices need not be physically organized in these
configurations
BUS and TREE Topology
TREE Topology branch with multiple nodes.
STAR Topology
- used in Ethernet and Token Ring
- 5 to 100+ devices
OSI Reference
Model
Application layer, Presentation layer, Session layer,
Transport layer [segment]
Network layer [packets], Data link layer [frame], Physical
layer [bits]
APPLICATION LAYER
- Provides network services to application processes like e-mail, File Transfer, and Terminal Emulation.
PRESENTATION LAYER
- Data representation
- Ensures data is readable by receiving system
- Format of data
- Data structure
- Negotiates data transfer syntax for application layer
- Compression, decompression, encryption and decryption
SESSION LAYER
- Inter-host communication
- Establishes, manages, and terminates sessions between applications
TRANSPORT LAYER
- End-to-end connection reliability
- Concerned with data transport issues between hosts
- Data transport reliability
- Establishes, maintains, and terminates virtual circuits
- Fault detection and recovery
- Information flow control
NETWORK LAYER
- Addresses the best path
- Provides connectivity and path selection between two end systems
- Domain of routing
DATA LINK LAYER
- Access to media
- Provides reliable transfer of data across media
- Physical addressing, network topology, error notification and flow control
PHYSICAL LAYER
- Binary transmission
- Through wires, connectors, voltages, data rates
TCP/ IP
A suite of protocols
TCP
- Rules that dictate how packets of information are sent across multiple networks
- Addressing
- Error checking
IP
- Determines where packets are routed based on their destination addresses
- Breaks packets into smaller packets and reassembles them.
DOD model OSI model
Application / process Application
Presentation
Session
Host-to-host Transport
Internet Network
Network Access Data
link
Physical
TCP/IP PROTOCOL
SUIT
PROTOCOLS
The Process / Application layer protocols
- Telnet – Terminal Emulation
- allows a user on a remote client machine called the Telnet client, to access the resources of another machine, the Telnet Server [ virtual terminal ]
[Port no. 23]
- File Transfer Protocol
- FTP is a program operating as protocol
- Used for file transfer between two systems
- Can access both directories and files and can accomplish certain types of directory operations.
- FTP uses Telnet to transparently log on to FTP server.
- Uses authentication secured with user names and passwords.
** Directory Manipulation
- Typing file contents
- Copying file between hosts
- It can’t execute remote files as programs. [ port no. 21]
- TFTP – Trivial File Transfer Protocol
- Stock version of FTP
- Fast
- No directory-browsing abilities
- Sends or receive much smaller blocks of data than FTP
- No authentication, so its insecure [port no. 69]
- NFS – Network File System
- protocol specializing in file sharing
- allows two different types of file system to interoperate port no
- SMTP – Simple Mail Transfer Protocol
- Used to send mail or e-mail
- POP 3 used to receive mail [ port no. 110]
- Port no. 25
- LPD – Line Printer Daemon
- designed for printer sharing
- LPD along with LPR [ Link Printer Program]
- Allows print jobs to be spooled and sent to network printers using TCP/IP
- Port no.
X WINDOWS
* Designed for client-server operations on a GUI
* Port no.
SNMP – Simple Network
Management Protocol
- collects and manipulate valuable network information
- it receives BASELINE – a report delimiting the operation traits of a healthy network
- this protocol stands as watch dog [ AGENTS ]
- Agents send an alert called a TRAP to the management
- Port no. 161 / 162
DNS – Domain Name
Service
- it resolves host name alternative to IP address
- port no. 53
DHCP – Dynamic Host
Configuration Protocol
- it assigns IP address to hosts
- can provide following information
* IP, subnet mask, domain name,
default gateway, DNS, WINS
BOOTP – Boot strap
protocol
- port no. 67,68
NETWORK PROTOCOLS
1.
IPX / SPX–
Inter Network Packet Exchange / Sequenced
Packet Exchange
Netware Core
Protocol developed by Novell.
2.
NETBIOS /
NETBEUI
Network Basic Input Output System / NETBIOS
Enhanced User Interface
Developed by IBM
refined by Microsoft
Used by Windows
NT for LAN management
For file and
printer sharing
3.
TCP /
IP
Set of protocols
used in Internet
4.
APPLETALK
Used by MACINTOSH
computers
5.
DLC /
Data Link Control – developed by IBM
To connect Token-
ring based workstations to IBM mainframe.
Also used by
printer manufacturers to connect remote printers to network print servers.
Host-To-Host Layer
Protocols
- TCP – Transmission Control Protocol
- Connection-oriented
- Sequenced
- Full- duplex
- Reliable and accurate
- Error checking
- Segment ( 20 to 24 bytes )
- Windowing Flow control
- UDP – User Datagram Protocol
- Connection-less
- Fast
- No acknowledgement
- Un sequenced
- No windowing or flow control
Internet Layer
Protocols
1.
IP –
Internet Protocol
2.
ICMP –
Internet Control Message Protocol
- It is a management protocol and messaging service provider for IP
3.
ARP- Address Resolution Protocol
- finds the MAC address of the host from a known IP address
4.
RARP
– Reverse Address Resolution Protocol
- Requests for IP address with help of MAC address in diskless machines
IP HEADER
Source IP address 131.107.7.29
Destination IP address 131.107.3.44
Protocol TCP
or UDP
Checksum 4
DF 5
Time to Live [TTL] 60
TTL – value which
determines how long the packet lives on the wire before it’s discarded
IP on the router
- Decrements the TTL
- Calculates new checksum
- Obtains hardware address
- Forwards the packet
In IP layer, the packet is defragmenter into three parts.
Each part has the following information (header)
Eg. FLAG
Indicates other fragment follows
Flag is not added to the last packet because no other
fragments follow it
FRAGMENT ID
Identify all fragments that belong together
FRAGMENT OFFSET
IP ADDRESS [32 bit – 4 octets] IPV 4
IPV 4 – 32 bits
IPV 6 – 128 bits
Subnet mask
Class A – 255.0.0.0
Class B - 255.255.0.0
Class C - 255.255.255.0
Subnetting
- Reduce network traffic
- Optimized network performance
- Simplified management
- Facilitates spanning of large geographical distances
0741CISCO LAYERS
1. Core Layer:
Responsible for transporting large
amounts of traffic both reliably and quickly to switch traffic as fast as
possible
2. Distribution layer (workgroup
layer):
Routing
Implementation of tools such as
access lists, packet filtering, address translation, firewall
Redistribution
between routing protocols, including static routing
Routing between VLANs,
and other workgroup support functions
Definitions of
broadcast and multicast functions
3. Access layer (desktop layer)
Static routing,
demand dynamic routing and Ethernet switching
CISCO HARDWARE
BASICS
ROUTER
1.
Microprocessor ( MOTOROLA 68030 series OR
Orion/R4600 series
2.
Motherboard / Chipsets
3.
Memory
Dynamic RAM (volatile)
– current configuration file [Running – config]
NVRAM
[Non Volatile] – shared configuration file [Starter – config]
SRAM(STATIC DYNAMIC RANDOM ACCESS MEMORY)
FLASH
- IOS resides
ROM
[BIOS]
§ POST
§ BSL
– Boots from : FLASH / TFTP / MINI IOS
§ MINI
IOS
4.
Interfaces
Console [con 0]
Asynchronous serial port [RS 232]
Connects to Com
port of the system
Auxiliary port [Aux 0]
For remote configuration
Supports modem
5.
LAN Interface
AUI [Attachment User Interface]
Ethernet E 0
Others - Fast Ethernet, Gigabit
Ethernet, Token Ring, FDDI
6.
WAN Interface
i.
Serial 0
ii.
Serial 1
iii.
Others:
ISDN, Frame Relay, ATM, DSL, VOIP
7.
I / O Slots
EDITING TOOLS
Ctrl A – move cursor to beginning of the line
Ctrl E - move cursor to end of the line
Esc B - move cursor back one word
Esc F - move cursor forward by one word
Ctrl B - move cursor back by one character
Ctrl F – move cursor forward by one character
Ctrl D or Backspace – deletes a single character
Ctrl U – Erase a line
Ctrl R – redisplays a line
Ctrl W – erase a word
Ctrl Z – ends the configuration mode and returns to Exec
mode
Tab – finishing typing a command
Ctrl P – shows last command typed
Ctrl N – shows previous command entered
IOS BASIC COMMANDS
Router >? Help
Router > show? Lists
all the commands in Show
Router > s? Lists
all the commands starting with ‘S’
Router > show terminal shows
terminal configuration and history buffer size
Router > show version shows
the version
Router > show flash shows
details of ‘flash’
Router > enable
to enter privilege exec mode
Router # show history show
last ten commands
Router # terminal history size 20 to set history size to 20
Router # show running-configuration to display contents of Dynamic RAM
SETTING PASSWORDS
1.
To
set console password
Router>enable
Router# config t
Router (config) # line console 0
Router (config-line) # login
Router (config-line) # password
Router (config-line) # Ctrl Z
Router# wr – to save the settings
2. To set privilege password
Router>enable
Router# config t
Router (config) # enable secret
Router (config) # Ctrl Z
Router# wr
3. To set telnet password
Router>enable
Router# config t
Router (config) # line vty 0 4
Router (config-line) # login
Router (config-line) # password
Router (config-line) # Ctrl Z
Router# wr
4. To set auxiliary password
Router>enable
Router# config t
Router (config) # line aux 0
Router (config-line) # login
Router (config-line) # password
Router (config-line) # Ctrl Z
Router# wr
- Encrypting password
Router>enable
Router# config t
Router (config) # service
password-encryption
Router (config) # Ctrl Z
Router# wr
- To recover passwords
o The
default configuration register value is 0 * 2102
o To
ignore NVRAM content register value is 0 * 2142
Step 1. Press Ctrl + Break when router boots
Step 2 types 0 after creating break
>0
>o/r
0 * 2142
>
I
..
..
Want
to go to setup mode [Y/N]: N
NAT – NETWORK ADDRESS
TRANSLATION
NAT allows a host that does not have a valid registered IP
address communicate with other hosts through the internet
NAT uses a valid registered IP address to represent the
non-registered IP address
PRIVATE ADDRESS
o Non-registered
IP address used inside a network
RANGE IP ADDRESS
CLASS A – 10.X.X.X (10.0.0.0 to 10.255.255.255)
CLASS B - 172.16.X.X (172.16.0.0 to 172.31.255.255)
CLASS C - 192.168.X.X (192.168.0.0 to 192.168.255.255)
NAT -
Static
Dynamic
Overloading
Static NAT
1 private
address: 1 public address
Eg: private public
10.1.1.1
200.1.1.1
10.1.1.2
200.1.1.2
10.1.1.3
Router (config) # IP nat inside source static
192.168.10.1. 200.1.1.1
Router (config) # int e 0
Router (config # ip nat
inside
Router (config) # int s 0
Router (config) # ip nat outside
Router# show ip nat translation
Static NAT
Dynamic NAT
·
Sets up a pool of possible inside Global address
and defines criteria for the set of inside local IP addresses whose traffic
should be translated with NAT
·
Address is dynamically assigned
Dynamic NAT
|
Dynamic NAT
Router (config) # access-list 1 permit 192.168.10.0 0.0.0.255
Router (config) # ip nat inside source
list 1 pool hcl
Router (config) # ip nat pool hcl 200.0.0.1 200.0.0.5
netmask 255.255.255.0
Router (config)#int
e 0
Router (config)#
ip nat inside
Router (config) #int s 0
Router (config) #ip nat outside
Router (config) #debug ip nat [*ping from source]
Router (config) #show ip nat translation
PAT
Router (config) #ip nat inside source list 1 pool hcl
overload
Router (config) #ip nat pool hcl 200.1.0.1 200.0.0.2 netmask
255.255.255.0
Router (config)#int
e 0
Router (config)#ip
nat inside
Router (config) #int s 0
Router (config)#ip nat outside
Router (config) #debug ip nat [*telnet from source]
Router (config) #show ip nat translation
Overloading NAT
with PAT
PAT – Port
Address Translation
to support lots of inside local IP
addresses with only a few inside Global, publicly registered IP address, NAT
overload uses PAT. Instead of just
translating the IP address, it also translates the port number.
IP ROUTING
1.
Static
2.
Default
3.
Dynamic
Static Routing
Administrator manually adds routes in each router’s routing
table.
Command
Ip route < destination network > < mask > <
next hop add or exit interface > < administrative distance > <
permanent
Eg. Ip route 192.168.10.0
255.255.255.0 192.168.20.1
To show routing table
# Show ip route
Default Routing
Used in stub network where there is only one way
Ip route 0.0.0.0
0.0.0.0 192.168.20.1
Administrative
distances
Rate the trust worthiness of routing information received on
a router from a neighbour router.
Default
administrative distance
Connected interface 0
Static route 1
EIGRP 90
IGRP 100
OSPF 110
RIP 120
External EIGRP 170
Unknown 255
(this route will never be used)
DYNAMIC ROUTING
Protocols are used to find networks and update routing
tables on routers
Routing protocols
Used to determine the path. Eg. RIP, IGRP, EIGRP,OSPF etc
Routed protocols
That carries the packets, e.g. IP, IPX, and AppleTalk.
Routing protocols
* Interior Gateway
Protocols- used to exchange information inside the same autonomous system.
* Exterior Gateway
Protocols - to communicate between autonomous systems. Eg. BGP
IGP à
Distance vector à
RIP, IGRP
à Link State à
OSPF, NLSP
à Hybrid à
IS-IS, EIGRP
RIP à
Routing information protocol
IGRP à
Interior Gateway Protocol (Cisco proprietary)
OSPF à
Open Shortest Path First
NLSP à
Network Link Service Protocol
IS-IS à
Intermediate System- Intermediate System
EIGRP à Enhanced IGRP (Cisco proprietary)
RIP IGRP
1. Max. Hop is 15 Max.
Is 255, default is 100
2. Metric is
hop Composite
metric (Bandwidth and
Delay)
default
Also
Reliability, load and MTU
(Maximum
Transmission unit)
3. No asynchronous uses autonomous system no.
4. Full route
table update every 30 sec 90 sec
5.
Administrative Distance 120 100
6. Route by ‘R’ Route
specified by ‘I’
RIP V1 OSPF
1. Maintains one table. Maintains 3 tables
A.
routing table
B.
topology table
C.
neighboring table
2. Maintains
one path to destination maintains
multiple path
3. Advertise /
update every 30 sec every
30 mins
4. Advertise
are broadcast packets. Multicast
packets
5. Entire
routing table advertised. Only
changed entries
6. High
traffic, bandwidth consumption less
traffic, no bandwidth consumption
And full in performance.
7. The metric
is hop. Bandwidth,
time delay, cost, traffic.
8. Max. Hop is 15, 16th unreachable. Unlimited.
9. Doesn’t support classless routing. Support classless routing.
10. The route specified by ‘R’. Route specified by ‘O’.
11. Administrative distance is 120. AD is 110.
12. Delay in
convergence. No
delay in convergence.
13. Bellman
ford Algorithm. Dijkshetra
Algorithm.
EIGRP
- Multiple paths to destination.
- Classless routing.
- Cisco proprietary protocol.
- Supports IP, IPX, Appletalk.
- DUAL Algorithm ( Diffusion Update Algorithm)
- Reliable Transport protocol (RTP) for advertise.
- Multiple autonomous systems in same router.
- AD is 90.
- Route is ‘D’.
- Metric – Bandwidth, time delay, cost, traffic.
Extra commands to verify the
configuration
# Show
protocols àdisplays
all the routed protocols and the interfaces upon which is enabled
# Show ip
protocols à
shows only ip protocols
# debug ip rip
# Debug ip igrp
events à
source destination updates and no. of routers
# Debug ip igrp
transactions à
show transactions
# undebug
all à to turn off debugging
Or
# UN all
Configuration of RIP
Router (config)
# router rips
Router (config-router)
# network 192.168.10.0 (e 0)
Router (config-router)
# network 192.168.20.0 (s 0)
Router (config-router)
# exit
Router # show
ip route
OSPF used LSO (Link
State Update) – to indicate the other router to update with the new link
status, when the old fails.
RIP propagations
Router (config-router)
# passive-interfaces s 0
Allows
receiving rip updates but does not send out any updates
Configuring IGRP
# Router igrp
10
# Network
192.168.10.0
# Network
192.168.20.0
EIGRP
- classless , distance vector protocol
- communicates with other routers via, RTP ( Reliable Transport Protocol )
- selects the best path via Diffusing update algorithm ( DUAL )
- Supports IP, IPX, Appletalk
- Supports multiple autonomous system on a single router
- Supports VLSM and summarization
- Metric – bandwidth, delay ,load and reliability
Configuration
EIGRP
Router # config t
Router (config) # router eigrp 20
Router (config-router) # network 192.168.10.0
Router (config-router) # network 10.0.0.0
To prohibit the
interface from sending or receiving hello packets
Router (config) # router eigrp 20
Router (config-router) # passive-interface s 0
Verifying EIGRP
# show ip route eigrp
# show ip eigrp neighbors
# show ip eigrp topology
Trace route command
Router # trace route 192.168.10.2
Open Shortest Path
First [OSPF]
OSPF calculates the best/shortest path to every network in
the same area based upon the information collected in Topology database and
algorithm called SPF (shortest path first)
Configuration
Router (config) # router Ospf 20
#
Network 10.0.0.0 0.255.255.255 area 0
Very configuration
#
Show ospf interface
#
show ip ospf neighbour
#
Show ip protocols
#
show ip ospf database
ACCESS CONTROL LISTS
- Standard [ 1-99 ] [ 1300- 1999]
- Extended [100-199] [2000-2699]
- Named access list
Standard – all
decisions are made based on source IP address
Router (config) #
access-list < number > [deny/ permit] [host any]
Router (config) # access-list 10 deny host 172.16.30.2 (to deny a single host)
Router (config) # access-list 10 deny 172.16.30.0 0.0.0.255
Router (config) # access-list 10 permits any
Router (config) # int e 0
Router (config-if) # ip access-group 10 in
Router (config-if) # int s 0
Router (config-if) # ip access-group 10 out
# Show ip
interface
# Show
access-list [access-list no/ access-list name]
# Show ip
access-lists [access-list no/ access-list name]
# show
running-config
Extended Access list
Checks source address and as well as destination address. It
can block depending upon port no.
# ip access-list 101 permit tcp 12.0.0.0 0.0.0.0
10.0.0.1 0.0.0.0 eq 21
# ip access-list 101 permit tcp 12.0.0.3 0.0.0.0
eq 23
# ip access-list 101 deny tcp host 12.0.0.5
# ip access-list 101 permit ip any any
Standard access list
# Ip access-list standard Siva
Std- nacl # deny 12.0.0.0
# permits any
# Exit
# Int e 0
# Ip access-group Siva out
WAN TECHNOLOGIES
Types of WAN connections
1.
Leased line connections
2.
Circuit switched connections
3.
Packet switched connections
Leased-line
connections
- can be called a point-to-point ( dedicated connection )
- Provides a single, pre-established WAN communication path.
- Synchronous
- Speed T3 ( 45 Mbps )
- Synchronous communications involve digital signals that are transmitted with precise clocking
- Very expensive.
Circuit-switching
- Provides a dedicated physical circuit, which stays in place between the sender and the receiver for the duration of the communication session.
- Telephone company network uses the system to provide basic telephone services or ( ISDN – Integrated Services Digital Network )
- Basic telephone services are asynchronous serial communication.
Packet-switching
- Packet-switching method involves network devices sharing a single point-to-point link.
- Point-to-point link is used to transport packets from source to destination over a telecommunication carrier network.
- Statistically programmed switching devices provide physical connections
- Packet headers are used to identify the destination
- Less expensive
- Synchronous serial lines
- Speed 56 Kbps ( T3 )
Physical items needed
for WAN link
1.
Customer Premises Equipment ( CPE )
2.
A Demarcation ( DEMARC )
3.
A Local loop ( last mile ) – copper wire
4.
a central office ( CO ) switch
5.
a full network
Types of serial cable
supported by CISCO devices
Serial cables can support leased-lines and packet-switched
connections.
1.
EIA / TIA – 232
2.
EIA / TIA – 449
3.
EIA / TIA – 530
4.
X.25
5.
V.35
DTE – Data Terminal Equipment is your CPE.
DCE – Data
Communication Equipment – to convert the user data from DTE into a form that’s
acceptable to the WAN service provider
The synchronous serial ports can be configured a either DTE
or DCE, depending on the attached cable.
EIA / TIA – 530 serial ports can be configured as DTE only.
- External clocking from the channel service unit/ data service unit ( CSU/DSU ) or other DIC device is needed when the port is configured as DTE.
- When traffic is crossing the WAN link, each WAN connection uses a protocol to encapsulate it.
- WAN encapsulation protocols operate at layer 2 of the OSI model.
- The choice of encapsulation protocol depends on the WAN technology and the communication equipment.
WAN protocols
1.
HDLC –High-level Data Link Control
2.
PPP – Point-to-point protocol
3.
SLIP – Serial Line Interface protocol
4.
X.25
5.
Frame Relay
6.
ATM – Asynchronous Transfer Mode
HDLC – frame format
HDLC
- The default encapsulation type on point-to-point, dedicated link is HDLC.
- It’s typically used for communication between two Cisco devices and is a bit-oriented synchronous protocol.
SLIP
- SLIP predates PPP.
- It uses a variation of TCP/IP and is a standard protocol for point-to-point serial connections
PPP
- PPP provides router-to-router and host-to-network connections over synchronous and asynchronous circuits.
- Can work with IP and IPX.
- Security mechanisms such as PAP (Password Authentication Protocol) and CHAP (Challenge Handshake Authentication protocol) are built into PPP.
Configuring PPP
Router (config) # int s 0
Router (config-if) # encapsulation PPP
Router (config-if) # exit
Configuration PPP
authentication
Step 1. Setting
username, password for remote router connecting to your router
Router (config) # hostname Router A
Router A (config) # username Router B password Cisco
Router A (config) # # exit
Step 2. Configuring PAP or CHAP
Router A (config) # int s 0
Router A (config-if) # PPP authentication chap pap
Router A (config-if) # exit
Verifying PPP
encapsulation
Router A # show int s 0
PAP
contains four main components
1.
A physical layer International Standard for
serial communication. I.e. EIA/TIA 232 C, V.24, V.35, and ISDN.
2.
A method for encapsulating datagram over serial
links. i.e. HDLC.
3.
A method of establishing, configuring,
maintaining and terminating the point-to-point connection. LCP – Line Control
Protocol
4.
NCP – Network Control Protocol – to allow
communications of multiple network layer protocols.
PPP Session
Establishment
1.
Link-Establishment Phase – uses LCP.
2.
Authentication Phase
a. CHAP
( Challenge Handshake Authentication protocol )
b. PAP
( Password Authentication Protocol )
3.
Network Layer protocol phase – NCP
X.25
* It is a ITU-T standard (International Telecommunication
Union – Telecommunication Standardization sector.
* It is an International body that develops world wide
standards for telecommunication technologies.
* It defines how connections between DTE and the DCE are
maintained.
* These connections are used for remote terminal access and
computer communication in public network.
* X.25 is a precursor of frame relay, and it specifies Link
Access Procedure Balanced ( LAPB ),
which is a data-link layer protocol.
Frame Relay
- It is an Industry Standard Protocol.
- It can handle multiple virtual circuits, and is streamlined to cut out some of the lengthy processes that X.25 employs.
ATM
- It is an International Standard for cell relay.
- Cell relay is a network technology based on the use of small, fixed-size packets or cells.
- It allows data, voice, and video to be conveyed in fixed-length cells of 53 bytes.
- Fixed-length cells reduce transportation delays by allowing processing to occur in hardware.
- ATM used high speed transmission media such as
- E3 ( 45 Mbps)
- T3 ( 56 Kbps)
- SONET ( Synchronous Optical Network )
Configuring 1900
Series Switch
- User(s) how active on management console
- User interface menu
[m] Menus
[k] Command line
[i] ip configuration
Enter selection: k
Switch > enable
Switch # config t
Switch (config) # enables password
level 1 Cisco
(Setting password for user mode)
Switch (config) # enables password
level 15 Cisco
(Setting password for enable mode)
Switch (config) # enables secret
Cisco
(Setting secret password for enable mode)
Switch (config) # hostname
1900switch
(Setting hostname)
#
Ip address 192.168.10.1 255.255.255.0
#
Ip default-gateway 192.168.10.2
To show VLAN information
Switch # show vlan brief
To show information about VLAN 2
Switch # show vlan id 2
To view the Spanning Tree information for a VLAN
Switch # show spanning-tree vlan 2
Assigning IP address to a switch
Reason - * for using Telnet
To connect to router for inter-vlan
* IP address should be given to
default vlan i.e. vlan 1
Switch > enable
Switch # config t
Switch (config) # int vlan 1
Switch (config –if) # ip address
172.16.10.3 255.255.255.0
Switch (config –if) # no shutdown
Switch (config –if) # exit
Switch (config) # ip
default-gateway 172.16.10.1
Switch (config) # exit
ISDN –
Integrated Services Digital Network
ISDN Switch types
Type Keyword
1. AT/T
basic rate switch basic-5
ess
2. Nortel
DMS – 100 basic rate switch basic-dms
100
3. National
ISDN-1 switch basic-ni
4. AT & T 4 ess (ISDN Pri only) Primary- 4 ess
5. AT
& T 5 ess (ISDN Pri only) Primary-5
ess
6. Nortel
DMS -100 (ISDN pri) Primary-
dms 100
Dial-on Demand Routing ( DDR)
Router A (config) # ip route
172.16.60.2 255.255.255.255 bri 0
DDR with Access-lists
Router (config) # dialer-list 1 protocol ip list 110
# access-list 110 permits tcp any any
eq SMTP
# access-list 110 permits tcp any any eq
telnet
# Int bri 0
# dialer-group 1
Configuring the Dialer information
Router (config) # int bri 0
# Ip address 172.16.60.1 255.255.255.0
# no shut
# Encapsulation PPP
# dialer-group 1
# Dialer string 8350661
Or
# Dialer map ip 172.16.60.2 name
Router B 8350661
Basic Rate ISDN (BRI)
- 2 B + D = 16 Kbps
- 2 B = 64 Kbps
- Q 921 & Q 931 for D channel signaling
- SS 7 to set up the path
Configuring ISDN
Router A > enable
Router A (config) # isdn switch-type basic-dms 100
Router A (config) # int bri 0
Router A (config-if) # encapsulation ppp
# Isdn sped 1
# Isdn sped 2
SPID –Service
provider identification
Verifying ISDN
connections
# Show dialer
# Show isdn status
# Show ip route
Frame-Relay
configuration
Router (config) # int s 0
Router (config-if) # encapsulation frame-relay ( cisco or
ietf)
# Ip address 192.168.10.1 255.255.255.0
# frame-relay lmi-type ansi
# frame-relay interface-dlci 101
# Exit
Monitoring frame
relay
# Show frame lmi
# Show frame PVC
# show int s 0
LMI – Local
Management Interface
- signaling standard used between the router and first frame relay switch
- Standards are * CISCO
- ANSI
- Q.933A
DLCI – Data Link
Connection Identifier ( !6-1007 )
- Given by the service provider to identify the PVC ( Permanent Virtual Circuit )
- IETF – Internet Engineering Task Force
Resolving
hostnames
1.
Building host table
2.
using DNS
- Building host table
- IP host < hostname > < tcp port no > < ip address >
Eg. Router (config) # ip host iiht
192.168.10.1
To see the host table
Router # show hosts
- Using DNS
Router (config) # ip domain-lookup
#
Ip name-server 192.168.10.1
#
Ip domain-name iiht.com
#
Exit
SWITCHING
·
Ethernet switches operate at layer 2 of the OSI
model and function in a similar way to bridges.
·
Ethernet switches and bridge forward and filter
traffic based on MAC address.
·
Switches and bridges identify host locations
through a process known as Address learning.
·
Switches and bridges provide Loop
avoidance function in a network.
·
When a switch is first initialized, its MAC data
base is empty. So it forwards the received message to all its port. This is
known as Flooding.
·
IEEE 802.1 Specifications defines a time limit
of 300 seconds for MAC database entries to remain in the database.
·
When the frame reaches the switch, the
destination MAC address is compared to the entries in the MAC database. The
switch then transmits the frame only to the port which matches the MAC address.
This is known as FRAME FILTERING.
·
Bridged and Switched networks are often designed
with redundant devices and links in order to prevent a single point of failure
in a network.
·
Redundant systems can cause bridge loops. Ie
problems caused due to bridge loops.
a. Broadcast
storms
b. Multiple
frame copies
c. Instability
in the MAC database.
·
Some layer-3 protocols use Time to line (TTL)
mechanism which eliminates looping packets.
·
TTL – Field in IP header to indicate how long a
packet can travel before it is returned or discarded.
·
Layer-2 protocols like Ethernet are unable to
prevent packets from endlessly looping.
·
To prevent broadcast storms, multiple frame
copies and MAC database instability, a loop avoidance mechanism is used. i.e.
SPANNING – TREE PROTOCOL ( STP )
·
STP is a link – management protocol that allows
redundant systems to exist in the network but prevents undesired bridge loops.
·
STP is a part of IEEE 802.LD standard, so it can
function with Complaint
Bridge and switches from
other vendors.
·
STP works by forcing certain redundant data
paths into a standby or blocked state.
·
When the topology of the network changes, STP
reconfigures bridge ports to prevent the creation of new loops or loss of
connectivity.
·
Each port on a bridge or switch is included in
STP support.
·
All switches in a LAN participating in STP
gather information on other switches in the network through an exchange of data
messages. This is known as BRIDGE PROTOCOL DATA UNITS ( BPDU )
ROOT BRIDGE
ELECTION
Default priority of the bridges is 32,678
Root
Bridge will be a bridge
with less Bridge ID. If the bridge ID is same for all the bridge, then the MAC
address is considered. A bridge with less MAC address will be the rest bridge.
Root path cost
Path cost = 1000 / speed in Mbps
Port Speed STP Cost
1 Gbps 1000/1000
= 1
100 Mbps 1000/10
= 10
10 Mbps 1000/10
= 100
56 Kbps 1000/56
= 17857
Root path will be path with less cost.
BPDU- BRIDGE PROTOCOL DATA UNITS
Information Length
Protocol 10 2
bytes
Version 1
Type 1
Flags 1
Root B ID 8
Root path cost 4
Sending B ID 8
Port ID 2
Message age 2
Max. Age 2
Hello time 2
Forward delay 2
Bridge ID
Bridge priority + MAC address
16 bytes +
48 bytes
Root Path Cost
Cost of the path from the Root Bridge,
identified by the bandwidth.
Root Port
Port connected to the root bridge.
Designated port
Port coming out of a root bridge towards the destination
Difference between
Bridge and Switch
Bridge Switch
1. Software
based Hardware
based, it operate with ASIC.
2. Uses software
based STP process Application-specific
Integrated Circuits and
a
high-capacity switching bus.
3. Slower faster
4. One spanning
tree instance per port many spanning tree
instance per port
5. Less number
of ports (max. 16) more number of
ports (>100)
6. Used to
separate LAN traffic into segments used
to connect directly to end-users and
other switches.
7. Cannot offer
dedicated bandwidth to each segment can
offer dedicated
Bandwidth
to end users
Two ways of
transmitting frame through a switch
1.
Store-
and – Forward
a. Forwarding
does not take place until the entire frame has been received by switch.
b. Switch
reads the destination and source address and performs CRC to ensure the frame
is not damaged.
c. If
damaged, the frame is discarded.
d. Latency
time is high since it has to check the frame and also varies with regard to
size of the frame.
Latency time is
the delay between receiving a frame and forwarding
2.
Cut-through
a. Forwards
the frame just by seeing the destination address only.
b. Latency
time is constant and less.
VLAN
- Static - Administrator creates VLAN.
- Dynamic – uses VMP3 (VLAN management policy server) to create VLANs.
Creating VLANs
1900 (config) # vlan 2 name sales
# Vlan 3 name mark
# Exit
# Show vlan
Assigning switch
ports
1900 (config) # int e 0/2
# vlan-membership static 2
# int e 0/3
# vlan-membership static 3
Configuring trunk
port
1900 (config) # int f 0/2l
#
Trunk on
·
1900 switch only runs on DISK (Dynamic ISC)
encapsulation.
VTP – VLAN Trunk
Protocol
1.
Messaging protocol that is used to distribute
VLAN Configuration information.
2.
Supports mixed-media backbones.
3.
Takes control of addition, detection, and name
changes on the network.
A VTP management domain can be either one switch or multiple
interconnected switching sharing the same VTP server.
VLANs are not propagated over the network until 2 VTP domain
name is specified or discovered.
VTP operates in
three modes.
- Server ( default )
- Client
- Transparent
Server mode
·
Switch acting at this mode can create, delete
and modify VLAN’s for the entire VTP domain.
·
Advertise its VLAN configuration
·
Synchronize its VLAN configuration with
information received from other devices in the domain.
·
Forward VTP advertisements received from other
switches in the domain.
·
It saves VLAN configuration into NVRAM and
recreates VLAN whenever the switch is booting.
Client mode
·
create VTP advertisements
·
synchronize its VLAN configuration
·
Forward VTP messages.
·
VTP transparent switch can create and modify
VLANs. But it is confined to the local switch only. It is not transmitted to
other switches in the domain.
·
Does not participate in domain.
** VTP advertisements are
automatically sent every five minutes or whenever a change occurs in a VLAN
configuration. Advertisement includes 1. Configuration-Version number
*** VTP PRUNING- technique that uses VLAN advertisements to
determine when a trunk connection is flooding messages unnecessarily.
Configuring VTP
1900 (config) # vtp server
# Vtp domain iiht
# Vtp password cisco
To see domain status, use
# show vtp (statistics)
To configure VLAN
Step 1. Configure VTP
(optional)
Step 2. Enable
trunking
Step 3. Create VLAN’s
Step 4. Assign switch ports to one or more VLAN’s
Step 5. Configure a
router for inter-VLAN communications (optional)
Step 1. Configure VTP
Switch > enable
Switch # vlan database
Switch (vlan) # vtp domain iiht
Switch (vlan) # vtp server
Switch (vlan) # exit
Switch (vlan)
To show the VTP details
Switch # show vtp status
Step 2. To enable Trunking
Switch # config t
Switch (config) # int fa 0/24
Switch (config) # switch port mode trunk
Step 3. Configuring VLAN
Switch > enable
Switch # vlan database
Switch (vlan) # vlan 2 names Siva
Switch (vlan) # vlan 3 name kumar
……….
………..
Switch (vlan) # exit
Step 4. Configuring ports
Switch > enable
Switch # config t
Switch (config) # int fast Ethernet 0/2
Switch (config-if) # switch port mode access
Switch (config-if) # switch port access vlan 2
Switch (config-if) # int fast Ethernet 0/3
Switch (config-if) # switch port mode access
Switch (config-if) # switch port access vlan 3
……………..
…………………
# Exit
Step 5. Configuring router for Inter-VLAN
Router > enable
Router # config t
Router (config) # int fa 0/0
Router (config-if) # no ip address
Router (config-if) # no shutdown
Router (config-if) # int fa 0/0.1
Router (config-subif) # ip address 172.16.0.1 255.255.0.0
Router (config-subif)
# encapsulation dot1q 1
Router (config-subif)
# int fa 0/0.2
Router (config-subif)
# encapsulation dot1q 2
Router (config-subif) # ip address ……………
………………
Router (config-subif) # exit
CDP – Cisco
Discovery Protocol
- to collect information about both locally attached and remote devices
- can gather hardware and protocol information about neighbour devices
CDP timers and hold
time information
Router # sh cdp
Sending packets every 60 sec
Sending hold time value of 180 sec
To configure cdp
timer and hold time
Router (config) # cdp timer 90
Router (config) # cdp hold time 24
Router (config) exit
To turn off cdp completely
Router (config) # no cdp run
To turn off cdp for an interface
# No cdp
enable
To turn on cdp for an interface
#
Cdp enables
Gathering cdp
information
- # sh cdp neighbour
- # sh cdp neighbor detail
- # sh cdp traffic
STP
- Definition – allows link redundancy and prevents layer two loops
- Port states
- BPDO
- Root election
- Root path cost
- Root and designated ports
- Convergence
Port States
Turn on the switch à Blocking à Enabled
à STP Disabled
- Listening – the port listens for any message regarding the blocking state. This listening time is known as Forward Delay Timer ( default is 15 sec)
- Learning (default 15 sec) – if no message is received regarding the blocking state till 15 secs the ports moves to the learning state. In learning state, the switch identifies where it is located in the topology and maintains a database for forwarding. ie. Is known as Forwarding database
- Forwarding state – forwards the data
NAT – Network
Address Translation
- allows a host that does not have a valid registered IP address communicate with other hosts through the internet
- NAT used a valid registered IP address to represent the non-registered IP address.
Private Address
- non-registered IP address used inside a network
Range
Class C – 10.X.X.X (10.0.0.0
to 10.255.255.255)
Class B - 172.16.X.X (172.16.0.0 to 172.31.255.255)
Class C - 192.168.X.X (192.168.0.0 to 192.168.255.255)
NAT
- Static
- Dynamic
- Overloading
Static NAT
1 private address: 1 public address
E.g. Private public
10.1.1.1
200.1.1.1
10.1.1.2
200.1.1.2
Static NAT
Router (config) # ip nat inside source static
192.168.10.1 200.1.1.1
Router (config) # int e 0
Router (config) # ip
nat inside
Router (config) # int s 0
Router (config) # ip nat outside
Router # show ip nat translation
Overloading NAT with
PAT
PAT – Port Address Translation
- To support lots of inside local IP addresses with only a few inside global, publically registered IP address. NAT overload uses PAT. Instead of just translating the IP address, it also translates the port number.
PAT
Router (config) # ip nat inside
source list 1 pool hcl overload
# Ip nat pool hcl 200.0.0.1
200.0.0.2 netmask 255.255.255.0
#
Int e 0
#
Ip nat inside
#
Int s 0
#
Ip nat outside
#
Debug ip nat (* telnet from source)
#
show ip nat translations
Dynamic NAT
- Sets up a pool of possible inside global address and defines criteria for the set of inside local IP addresses whose traffic should be translated with NAT.
- Address is dynamically assigned.
Router (config) # access-list 1 permit192.168.10.0 0.0.0.255
Router (config) # ip nat inside source list 1 pool hcl
Router (config) # ip nat pool hcl 200.0.0.1 200.0.0.5 netmask 255.255.255.0
Router (config) #
int e 0
Router (config) #
ip nat inside
Router (config) # int s 0
Router (config) # ip nat outside
# Debug ip nat (* ping from source)
Password recovery
Enable - go to privilege
mode
Router # copy startup-config running –config
Router # config t
Router (config) # enable secret < pw > à
change pw
Router (config) # exit
Router (config) # config-register 0*2102 à to reset original configuration
Router # copy running-config startup-config
Published By
S.G.Godwin Dinesh
Published By
S.G.Godwin Dinesh
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