Transcript File

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What is a Router ?
• Router is a device which makes communication between two
or more networks present in different geographical locations.
• Routers are data forwarding devices which work at layer 3
• Routers forward data based on logical addresses
(IP,IPX,Appletalk)
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Many companies are manufacturing Router :
•
Cisco
•
Nortel
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Multicom
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Cyclades
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Juniper
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Dlink
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Linksys
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3Com
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Cisco’s Hierarchical Design Model
Cisco defined the Router into 3 Layers
• Access Layer Router
• Distribution Layer Router
• Core Layer Router
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Access Layer Router
• Routers which are used by Small Organizations
• Used for end user connectivity
•
Router Series : 800, 1600, 1700, 2500,2600
Cisco 800
Cisco 1700
Cisco 1760
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Distribution Layer Router
• Routers which are used by the ISPs
• Used for policy based routing and access control
Router Series : 2600, 3200, 3600, 3700
Cisco 3600
Cisco 3700
Cisco 2600XM/2691
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Core Layer Router
• Routers which are used by the Global ISPs
• Used for fastest switching across internet
Router Series : 6400, 7200, 7300, 7400, 7500, 7600,
10000, 12000
Cisco 7000
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Modular Router
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Difference between Modular
Router & Fixed Router
 Fixed Router are just
• Modular routers are
like a brand PC where
just like assembled pc
modification of
where modification of
interface is not possible.
interface are possible.
 Access layer router are
• Distrubution and core
the example of fixed
layer routers are
router except 1600 and
example of modular
1700 series
routers.
Cisco 2501
AUI
Attachment
Unit Interface
E0
Serial Ports
S0 and S1
Console
(Con) 0
Power on/off
Switch
Auxiliary
(Aux) 0
Power
Supply
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Attachment Unit Interface
•
It is used for connecting LAN to the Router.
•
It is known as Ethernet Port or LAN port .
• AUI has 15 pin female connector (DB-15).
• Transceiver is used to connect RJ 45 to DB-15.
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Transceiver
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Attachment Unit Interface
An IP address is to be assigned to this interface and it
should be in the same network as of the LAN.
E0
192.168.1.150/24
Straight Cable
Straight Cable
1.1
1.2
1.3
LAN - 192.168.1.0/24
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Attachment Unit Interface
E0
192.168.1.150/24
Cross Cable
Cross Cable is used to connect AUI of
the router to PC-NIC
1.1
LAN - 192.168.1.0/24
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Crimping of Twisted pair Cable
• Straight cable
Used between unlike devices e.g. Hub to PC,
Switch to
PC, Hub to Router (AUI)
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Crimping of Twisted pair Cable
• Cross cable
Used between like devices E.g. : Hub to HUB,
PC, Switch to Switch, HUB to Switch,
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PC to
PC to Router.
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Crimping of Twisted pair Cable
• Rollover Cable
Used for connecting Router Console Port to PC Com Port or
Serial port.
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Serial Port
• Serial interface has DB60 connector (60 pins)
in fixed routers
• Smart Serial interface has DB26 connector in modular
routers.
• It is known as WAN Port.
• It is used for connecting Remote Locations using V.35 cable,
which has 60 pins (male connector) at one end and 18 pins
(male connector) on the other end.
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V.35 Cable
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V.35 Modem
S1
S0
E0
192.168.1.150
V.35
Cable
E0
192.168.2.150
V.35
Cable
2 pair of
Copper Wire
LAN - 192.168.1.0/24
LAN - 192.168.2.0/24
HYDERABAD
OFFICE
G.703
Modem
CHENNAI
OFFICE
EXCHANGE
G.703
Modem
HYDERABAD
MUX
CHENNAI
MUX
Fiber Optic Cable
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Console Port
• It is known as Local Administrative Port
• It is used for Initial Configuration
• Password Recovery
• It is RJ 45 port
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Console Connectivity
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Console Connectivity
•
Connect one end of the rollover cable to the router’s
console port (RJ-45 connector) and the other end of the
cable to DB-9 converter
•
Attach the female DB-9 converter to a PC Serial Port.
•
Open Hyper Terminal (when using a windows operating
system)
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Open minicom -s (when using a Linux operating system)
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DB9 Converter
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Auxiliary Port
• It is known as Remote Administrative Port
• Used for remote administration
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Auxiliary Connectivity
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Other Ports
• BRI Port
Basic Rate Interface used to connect ISDN.
It is available on 2503 and 2520 model routers
• 10 Base T Port
Used for connecting LAN to the Router. It is available on
2520 model router.
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2601 Model Router
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Brief Overview
• WAN interfaces
– Serial interfaces (S0, S1)
– ISDN interface (BRI0)
• LAN interfaces - Ethernet
– AUI (Attachment Unit Interface) (E0)
– 10base T
• Administration interfaces
– Console port
– Auxiliary port
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Internal Components
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Router Internal Components
•
The main internal components of the router are random-access memory
(RAM), nonvolatile random-access memory (NVRAM), flash memory, readonly memory (ROM), and interfaces.
Router Internal Components
RAM is used for
routing table
information and it
holds the running
configuration.
NVRAM is used to
store the
backup/startup
configuration file. Flash memory is
used for storage of
full Cisco IOS
software images.
The interfaces
provide LAN and
WAN connectivity.
ROM is used for
permanently
storing startup
diagnostic code.
The console port
provides physical
access for initial
configuration.
Boot sequence
POST
ROM
Power on Self Test
(verifies the hardware)
FLASH
Loads the Bootstrap Program
& Search where IOS is located
NVRAM IOS is found in Flash
RAM Ios searches the NVRAM
For startup Configuration File
NVRAM configuration is copied into
the RAM
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Routers
• Routers are mainly used as WAN devices.
• Routers use WAN connections to communicate with
each other.
• Routers are the backbone devices of large intranets and
of the Internet.
• They operate at Layer 3 of the OSI model, making
decisions based on network addresses.
Functions of a Router
• The two main functions of a router are to select the best
path for packets and to route packets to the proper
interface.
• Routers build routing tables and exchange network
information with other routers.
• Routers segment local area networks
Functions of a Router Initiated by
Router Configuration Files
•Selection of BEST PATH for data
•Controlling the flow of traffic in and out of the router (switching packets to
appropriate interface)
•Specifying the correct set up and use of routed and routing protocols
Routers do this by building a routing table and sharing that information with
other routers.
Difference between Routed
Protocols and Routing
Protocols
• Routed protocols are protocols that can be
• Routing protocol would be
OSPF, RIP, EIGRP, or BGP.
These are protocols that
distribute routing
information, throughout all
routers, on a network. By
each router knowing about
the networks that all others
routers have connected,
each router can determine
the best path to take to
delivery your traffic. Those
are Routing protocols.
sent over a routed network. Today, with IP
(think of TCP/IP) being the predominate
protocol in use on the Internet and in
most networks, we don't often think about
routed vs unrouted protocols. That is
because IP is a routed protocol. Meaning,
IP is designed such that it can be routed
over and through different networks. This
is because the IP address is broken up into
network and node (host) by the subnet
mask. An example of a protocol that is not
routed (unroutable) would be NETBIOS. It
works great on a small local network (in
your house) but wouldn't work well over a
large network connected by dedicated
network circuits or the Internet