Ccna R&S (Cisco Certified Network Administration) Routing And Switching
ABOUT CISCO :-
Cisco is founded in 1984 by Sandy Lerner
and Len Bosack.
Cisco goes public in 1990 and is listed on
the NASDAQ stock exchange.
More than 71500 employees.
Nearly 70000 channel partners.
More than 30000 CCIE professional.
CISCO CERTIFICATIONS PATH
CCENT CCNA R&S CCNP R&S CCIE R&S
Secuirty CCENT CCNA Security CCNP Security CCIE Security
Voice CCENT CCNA Voice CCNP Voice CCIE Voice
Wireless CCENT CCNA Wireless CCNP Wireless CCIE Wireless
Data Center CCENT CCNA Data
CCNP Data Center CCIE Data center
• Router is a layer 3 device.
• Router is used to connect two
• Router used as switch, firewall.
• Router also do packet filtering.
• Router always choose the best
path to route any packet.
• Router suppot unicast, multicast
but broadcast is not supported by routers.
CDP(CISCO DISCOVERY PROTOCOL)
• CDP protocol is cisco proprietry
protocol used by cisco device only.
• Cisco router and switch exchange the
cdp to each other in every 60 secound.
• CDP packet is used to show all the
information about cisco devices.
• By default every cisco device exchange
the cdp packets if we want to stop then
router(config)# Interface serial 0/0
router(config-router)# No cdp e
• The process of moving a packet of data from source to
destination and from destination to source is called
• A router may create or maintain a table of the available
routes and their conditions and use this information
along with distance and cost algorithms to determine
the best route for a given packet.
• Packet may travel through a number of network points
with routers before arriving at its destination.
• There are two types of routing:-
(1) Static Routing.
(2) Dynamic Routing.
Dynamic Routing Protocol
DISTANCE VECTOR ROUTING
LINK STATE ROUTING
1. Entire routing table is sent as an update.
2. Send periodic update (Every fixed interval of time
at every 30 secound).
3. Update are broadcast.
4. Update are sent to directly connected neighbour
5. Router donot have end to end visibility of entire
6. Routing loops may be exist.
1. Update are incremental.
2. Updates are triggered not periodic.
3. Update are multicast.
4. Update are sent to entire network.
5. Router have visibility of entire network.
6. No routing loop exist.
RIP (Routing Information Protocol)
• Rip is a Dynamic Routing Protocol.
• Rip is a Distance Vector Routing Protocol.
• It developed for smaller network.
• Rip calculate the best route based on hop count.
• Maximum numbers of hop is 15 after that it considered as
• Rip require less cpu power & ram.
• Rip uses 30 secound to update interval by default.
• Two version available in rip first is RIP V 1 and secound is
RIP V 2.
RIP VERSION 1 RIP VERSION 2
1. It support classfull routing.
2. Vlsm not supported.
3. Update message is sent to broadcast
4. No authentication support.
5. Rip version 1 donot support manual
summerization because it broadcast all the
routes on 255.255.255.255 without any subnet
1. It support classless routing.
2. Vlsm Supported.
3. Update message is sent to multicast address
4. Support plaintext and MD5 authentication.
5. Rip version 2 support manual
Routing Information Protocol Timers:-
1. Update Timer:-
In rip update timers is 30 secound by
default. It means that after every 30 sec rip send
thier whole update to thier neighbour router.
2. Hold down timer:-
In rip hold down timer is 180 secound
by default. It means that router hold the rip routes
only for 180 after 180 secound route will be invalid
but it will remain in routing table.
3. Flush Timer:-
In rip flush timer is 240 secound by
default. It means that router hold any route for 240
secound after 240 secound the route will be flushed
out from routing table.
COMMAND COMMAND'S PURPOSE
Rtr(config)#router rip Enables RIP routing process
Rtr(config-router)#network ip address Associates a network with a RIP routing process
Rtr(conifg-router)# timer basic 30 180 180 240
used to change timers in rip protocol.
Rtr#show ip route rip Used to display Rip routes.
Rtr#show ip protocol Used to display protocol information.
EIGRP(Enhanced Interior Gateway Routing
• It is an advanced distance vector routing
• EIGRP is used on a router to share routes
with other routers within the same
• Basic values in eigrp:-
AD- 90, 170
Max hop count- 255, By default- 100
• Eigrp choose thier best route by using the
metric values such as bandwidth, delay,
Gateway Routing Protocol)
1. Distance vector routing proctocol.
2. Metric - hop count limited to 15.
3. Update - periodic (send every 30
4. Max hop count- 15
5.Update- Broadcast (version 1)
1. Advanced distance vector routing
2. Metric - Bandwidth, Delay, Load,
3. Update- Triggered.
4. Max hop count - 255, 100
5. Update - Multicast
Hello packet is use send to discover
In hello packet router send thier parameters to
other router after every 5 secound.
Eigrp send two types of update
1. FULL UPDATE PACKET:- First
time eigrp send thier full topology information
in update packet.
2. PARTIAL UPDATE PACKET:-
After exchanging full update eigrp send partial
Eigrp send acknowledgement when it
recieve any packet from other router.
EIGRP NEIGHBORSHIP CONDITION:-
• Both router use same AS no.
• Metric weight should be same
on both side.
• Id authentication is enable
then configuration of
authentication is same on both
• Router must have to able to
send/ recieve ip packet to one
• Interface ip address must be
in same subnets.
Configuration of Eigrp:-
COMMAND COMMAND'S PURPOSE
Rtr(config)#router eigrp as no. Enables EIGRP routing process
Rtr(config-router)#network ip address Associates a network with a EIGRP routing process
Rtr#debug ip eigrp packets used to view real time EIGRP routing updates
Rtr(config-router)#show ip eigrp topology Used to display fs and successor in eigrp.
Rtr#show ip eigrp topology all-links Used to display all routing links in eigrp process.
OSPF(OPEN SHORTEST PATH FIRST)
• Ospf is a linked state routing protocol.
• In ospf every switch knows the whole topology
and information about connected router.
• Ospf create Graph and run the shortest path
first algorithm to choose the best path.
• To make ospf scalable we devide ospf process
into many areas.
• In ospf area 0 is called backbone area and
other areas are called non-backbone area.
• In ospf all areas will communicate via area 0.
A HELLO packet is a special packet (message) that is sent
out periodically from a router to establish and confirm network
This packet is used to check if the LSDB between 2 routers
is the same.
This packet is used to send request for database from its
This packet is used to carry the information of database from
one router to another.
This packet is used to give acknowledgement to thier
OSPF NEIGHBORSHIP STATES:-
When routers are down or ospf not run.
when we run ospf on routers and they will send hello
packet to each other and exchange thier parameters and
this proces is called initilization process.
• TWO WAYS:-
when routers exchange thier hello packet and
parameters are matched on both routers and they becomes
neighbors then we can say that they are in two ways state.
In exstart process both router decide who will start
data exchange process and who will end data exchange
process. They will go in master and slave election . one
router will become master and other will become slave.
OSPF NEIGHBORSHIP STATES (Cont....)
In exchange state router send
DBD packet which contain LSID i.e. They
only exchange header of database. Router-
id is become LSID.
In loading state they exchange
thier data base with each other. With the
help of LSR, LSU and LSACK packet.
When all router exchange thier data
base then they are in full state.
COMMAND COMMAND'S PURPOSE
Rtr(config)#router ospf process no. Enables OSPF routing process
Rtr(config-router)#network ip address Associates a network with a OSPF routing process
Rtr#debug ip OSPF packets used to view real time OSPF routing updates
Rtr(config-router)#show ip ospf database Used to display ospf information.
Rtr#show ip ospf Used to display all routing links in eigrp process.
ACL(Access Control Lists)
• ACLs are lists of conditions that are applied to
traffic traveling across a router's interface.
• ACLs can be configured at the router to control
access to a network or subnet.
• There are two types of ACLs
• ACL Limit network traffic and increase network
• If ACLs are not configured on the router, all
packets passing through the router will be allowed
onto all parts of the network.
NAT(Network Address Translation
• Network address translation is as the name suggests. It
translates one type of address into another. Lets take an
example. I have a network running with 172.16.1.0/24 as my
IP subnet. I want it to be converted/translated to
220.127.116.11/24 network when leaving a router interface.
• NAT will maintain a table of entries specifies which
172.16.0.0/24 addresses have been converted to
18.104.22.168/24 addresses so that when the return packet
comes it will be send to the right user. NAT translation will
be based on host basis .
• NAT is used to overcome the shortage of public IP space.
We can use private IP in our internal network and can use a
pool of public addresses when going to the internet.
DHCP(dynamic host configuration protocol)
• A DHCP server listens for DHCP requests and responds
by issuing an IP address. A DHCP server is built into most
home routers, and will assign a private network address
usually in 192.168.0.0/16 to any device that requests one.
• DHCP client starts by broadcasting the DHCP DISCOVER
packet. The broadcast is received by the DHCP Server(s),
which in turn replies with the DHCP OFFER message.
• The DHCP client may receive multiple DHCP OFFER
messages, however it chooses only one DHCP OFFER
message based on the policy configured in the DHCP
Client. Usually its on the first come first serve basis.
• The request is then sent to dhcp server and dhcp server
send ip address from its pool in ack packet.
• Frame Relay is packet-switched
• Frame relay works on layer 2 technology.
• Frame relay use serial links.
• Frame relay save the cost.
• We can also save address space by
using frame relay.
Frame relay use DLCI no. It is always
unique for new connection.
Frame relay send lmi packet to every
one as keep alive message.
• switch is a layer 2 device.
• switch works on mac address.
• It has single broadcast domain but
we can change the broadcast domain
by creating vlan.
• Single broadcast domain means all
the interfaces of switch are the
member of same vlan .
• By default all interface are in vlan 1.
• Switch is used to connect many users
VLAN provides Virtual
Segmentation of Broadcast
Domain in the network. The
devices, which are member of
same Vlan, are able to
communicate with each other.
The devices of different Vlan
may communicate with each
other with routing called Inter
VTP(Vlan Trunking Protocol)
• Vtp stands for vlan trunking protocol which
is used to share vlan information with each
• lets take an example if we have 100
switches and we need to configure three
vlans called as vlan 10 20 and 30 the initial
way to do it is to go to each and every
switch and configure vlans which becomes
a very hectic task and there are also a
chances for misconfigurations.
• In these cases vtp is used vtp is configured
on all the switches. One switch is kept in
vtp server mode and other in vtp client
mode. The vlans are then configured on
the server switch it immediatly deflects to
all the other 99switches which reduces the
STP(SPANNING TREE PROTOCOL)
• In switching spanning tree protocol
is used to control the loop.
• By default all switch forward the
BPDU message to each other. On
the basis of bpdu message switch
will decide thier Root Bridge who
control the stp process in vlan.
• Cisco switch run per vlan spanning
• In spanning tree protocol every
switch have one root port except
• Root port is always the best path to
reach the root bridge for non-root
• A Cisco technique that provides the ability
to negotiate to bundle multiple physical
links into a single, logical, higher speed
• Two types of protocol is used to form
Link Aggregation Control
Protocol, is used to dynamically build an
EtherChannel. There are different modes of
LACP. It can bundle 16 link at a time.
Port Aggregation Protocol is used
to achieve the same goal as LACP. But it can
bundle 8 links at a time.
• LACP MODE:-
The active end of the group sends out a LACP frame and initiates the negotiation to form the
EtherChannel. Both ends could be active and the result would be the same.
Passive Mode does not initiate the negotiation. It just responds to LACP packets initiated by
other end. So if both ends were passive, the EtherChannel would not be formed.
• PAGP MODE:-
In this mode, the negotiation will be initiated by sending the special frames to form
EtherChannel with the other end.
In this mode, negotiation is not initiated. It only responds to the special frames received for
negotiation form the other end. So, if both ends are in Auto mode, EtherChannel would not be formed.