37) The following are main features of route summarization
in EIGRP:
1. By default, EIGRP summarizes routes at the major
network boundaries (classful boundaries).
2. To enable summarization
at any level other than major network boundary, you need to disable
auto summarization using the command:
No auto-summary
3. The following command enables summarization at an arbitrary network
boundary:
Ip summary-address <as-number> <address-mask>
4. Note that you need to specify the IP address and routing
mask of the summary route. No need to specify the metrics.
38)The following are the advantages of LAN segmentation
using VLANs:
1. Segmentation of broadcast domains using VLANs
result in creation of more bandwidth per user.
2. Security is
provided by isolating users corresponding to different VLANs. Users
belonging to one VLAN will not receive frames mean for some other
VLAN.
3. LAN segmentation using VLANs can be done based on job
function rather than physical location, if required.
The following are true about CDP:
1. CDP - Cisco Discovery
Protocol is a Cisco proprietary Layer 2 protocol.
2. CDP uses
a multicast packet to the common destination address 01-00-0c-cc-cc.
3. CDP packets are sent out with a non zero TTL after an interface
is enabled and with a zero TTL value immediately before and interface
is made idle. This enables the neighboring devices to quickly discover
the state of neighbors.
4. CDP packets will never be forwarded beyond the directly connected devices. To find CDP information on indirectly connected routers, administrators can 'telnet' to the intended destination device and run CDP command.
39)The following are true about Frame Relay:
1. Frame
Relay is purely, a Layer 2 standard.
2. Frame Relay DLCIs have
local significance.
3. Cisco supports three types of LMIs (Link
Management Interface): cisco, ansi, and q933a
4. Cisco supports
two types of Frame Relay encapsulation: cisco, and ietf. When you
are connecting a Cisco router with a non-Cisco router, use ietf
as the encapsulation method.
40)The following are true about Multipoint, and point-to-point
Frame-Relay configuration at sub-interfaces:
1. In multipoint,
all interfaces use same subnet, whereas, in point-to-point each
pair requires its own subnet.
2. No IP address is defined at
the physical interface, if sub-interfaces are used for frame-relay
configuration.
3. Point-to-point sub-interfaces act as point-to-point
leased lines.
4. You must specify either multipoint or point-to-point
when configuring the frame-relay interface. There is no default
configuration assumed.
5. Point-to-point configuration is good
for star and partial mesh topologies, where as multipoint is suitable
for full mesh topologies.
The following command configures a static NAT translation by
mapping inside local address to the inside global address.
ip
nat inside source static 192.168.0.100 88.248.153.137
Here, 192.168.0.100
is the inside local address, and 88.248.153.137 is the inside global
address. A packet's source address 192.168.0.100 is changed to 88.248.153.137
by the NAT device.
41)The following commands can be used to view access lists:
sh ip access-list
sh access-list 146
The command sh ip access-list
displays all ip access lists including access-list 146.
The following information can be interpreted from the given command:
1. RouterB ip address is 192.168.68.1
2. RouterB platform is
cisco 4500
3. The CDP information is received on Ethernet0/1
of RouterA, and sent through Ethernet0 of RouterB
42)The following protocols support automatic route summarization
at major network boundaries.
1. RIP v1
2. RIP v2
3. IGRP/EIGRP
Note that OSPF does not support auto-summarization of routes.
The following statements permits access to VTYs (Router command
prompt) from the 192.168.1.0/24 netblock while denying access from
everywhere else:
RTA(config)# access-list 1 permit 192.168.1.0
0.0.0.255
RTA(config)# line vty 0 4
RTA(config-line)# access-class
1 in
The following three LMI type are supported by Cisco:
1. Cisco
(default)
2. ANSI
3. Q933a
43)The following two statements are true about dynamic
NAT translations:
1. The inside IP addresses eligible for address
translation are defined in a standard IP access-list.
2. Only
packets moving between inside and outside networks will get translated.
This is true even for static NAT. If a packet is destined for another
host, but does not require to cross the NAT boundary, the packet
source /destination addresses are not translated. This is understandable,
since the packet is not crossing the inside network boundary.
The options available with switchport port security are:
1. Switchport port-security maximum {max # of MAC addresses
allowed}: You can use this option to allow more than the default
number of MAC addresses, which is one. For example, if you had a
12-port hub connected to this switch port, you would want to allow
12 MAC addresses�one for each device.
2. Switchport port-security
violation {shutdown | restrict | protect}: This command tells the
switch what to do when the number of MAC addresses on the port has
exceeded the maximum. The default is to shut down the port. However,
you can also choose to alert the network administrator (i.e., restrict)
or only allow traffic from the secure port and drop packets from
other MAC addresses (i.e., protect).
3. Switchport port-security
mac-address {MAC address}: You can use this option to manually define
the MAC address allowed for this port rather than letting the port
dynamically determine the MAC address.
44)The path cost in OSPF network is calculated using bandwidth. The formula used is [10^8 / Bandwidth]. For example, the cost of a 56kbps serial link is 1785. The default cost of a 10mbps Ethernet is 10. Higher the bandwidth lower will be the path cost.
The show frame-relay map privileged EXEC mode command shows the contents of the next hop protocol address to DLCI mapping table on the router.
To enable both data and VOIP traffice, a switch can be configured to provide two separate VLANs, one each for VOIP traffic and data traffic.
The switches 1900/2800, 2900XL series have IOS based command
line interface. The correct format for setting host name on IOS
based switches is:
Switch (config)#hostname <name>
ex:
Switch (config)#hostname las26
Note that the name can be from
1 to 255 alphanumeric characters.
45)The syntax for ping command is : "ping <destination_address>"
The following are possible responses to "ping" command:
Ping Explanation
Response
U destination Unreachable
C Congestion
experienced
! Successful receipt of echo reply
. Time out
? Packet type unknown
& Packet time to live exceeded
Ping
sends ECMP echo. Ping can be used with almost any type of Network
layer protocols including IPX, IP, VINES, AppleTalk etc.
46)There are three ways a router learns how to forward
a packet:
1. Static Routes - Configured by the administrator
manually. The administrator must also update the table manually
every time a change to the network takes place. Static routes are
commonly used when routing from a network to a stub (a network with
a single route) network.
The command is
ip route network mask
address/interface [distance]
ex: ip route 165.44.34.0 255.255.255.0
165.44.56.5
Here, 165.44.34.0 is the destination network or subnet
255.255.255.0 is the subnet mask
165.44.56.5 is the default gateway.
2. Default Routes - The default route (gateway of last resort)
is used when a route is not known or is infeasible. The command
is
ip route 0.0.0.0 0.0.0.0 165.44.56.5
The default gateway
is set to 165.44.56.5
3. Dynamic Routes - As soon as dynamic
routing is enabled, the routing tables are automatically updated.
Dynamic routing uses broadcasts and multicasts to communicate with
other routers. Each route entry includes a subnet number, the interface
out to that subnet, and the IP address of the next router that should
receive the packet. The commands to enable rip are:
router rip
network <major network number>.
47)There are three ways a router learns how to forward
a packet:
1. Static Routes - Configured by the administrator
manually. The administrator must also update the table manually
every time a change to the network takes place. Static routes are
commonly used when routing from a network to a stub (a network with
a single route) network.
The command is
ip route network mask
address/interface [distance]
ex: ip route 165.44.34.0 255.255.255.0
165.44.56.5
Here, 165.44.34.0 is the destination network or subnet
255.255.255.0 is the subnet mask
165.44.56.5 is the default gateway.
2. Default Routes - The default route (gateway of last resort)
is used when a route is not known or is infeasible. The command
is
ip route 0.0.0.0 0.0.0.0 165.44.56.5
The default gateway
is set to 165.44.56.5
3. Dynamic Routes - As soon as dynamic
routing is enabled, the routing tables are automatically updated.
Dynamic routing uses broadcasts and multicasts to communicate with
other routers. Each route entry includes a subnet number, the interface
out to that subnet, and the IP address of the next router that should
receive the packet. The commands to enable rip are:
router rip
network <major network number>.
48)There are two different VTP versions. VTP version 1
and VTP version 2. These versions are not interoperable. Version
1 is the default version. All switches in a given management domain
should be configured in either version 1 or version 2. Some of the
advantages of VTP version 2 are as below:
1. Token Ring support:
Supports Token Ring LAN switching and VLANs. If Token Ring is used,
this is the version required.
2. Version number auto propagation:
In case that all switches are capable of running Version 2, only
one switch need to be Version 2 enabled, Version number is automatically
propagated to others.
There may be times that you have lost the passwords for accessing
the router and need to recover from the lost passwords. ROM Monitor
(rommon), stored ROM is used for password recovery. By hitting special
Break key within the first 60 seconds of the router power-on, it
is possible to recover from lost passwords. Broadly, the sequence
of operations is as below (For a 2501 router):
a. Power cycle
the router by turning it OFF and ON.
b. Press Break key (key
configuration depends on the router type) within 60 seconds of power
on.
C. Use the rommon command O/R 0X2142
d. Use rommon command
INITIALIZE to load IOS
e. Skip the setup mode (by choosing NO
to configuration commands)
f. Enter privileged mode
g. After
entering the privileged mode, you can view the passwords by issuing
appropriate config commands.
49)To configure your router to do look-up for domain name
server, the correct syntax is:
ip name-server <ipaddress_of_server>
Here the ipaddress_of_server is the ip address of the DNS server.
To determine the wild card mask (this is similar to ACL wild
card masks), you need to compute the summary IP address, and subtract
it from 255.255.255.255.
Example:
Following are the NY Router
interface IP addresses::
S0/0.1: 172.16.12.1/30 subnet: 172.16.12.0
host range: 172.16.12.1 - 172.16.12.2
S0/0.2: 172.16.12.5/30
subnet: 172.16.12.4 host range: 172.16.12.5 - 172.16.12.6
S0/1: 172.16.12.13/30 subnet: 172.16.12.12 host range: 172.16.12.13
- 172.16.12.14
Fa0/1: 172.16.12.33/28 subnet: 172.16.12.32
Host range: 172.16.12.33 - 172.16.12.46
Fa0/2: 172.16.12.66/28
subnet: 172.16.12.64 Host range 172.16.12.65 - 172.16.12.78
The summary IP address for router NY is 172.16.12.1 255.255.255.128
or /25
The wild card mask is: 255-128 = 127
Therefore,
the IP address with wild card mask that represents all the interfaces
on router NY is: 172.16.12.1 255.255.255.127
50)To telnet to a switch, the following are required:
1. Assignment of ip address and subnetmask to the management vlan,
2. Assignment of default gateway IP address.
The following
are the typical steps in preparing a switch for telnet access:
Switch(config)# interface vlan <vlan-id>
Switch(config-if)#
ip address <ip-address> <subnet-mask>
Switch(config-if)#
ip default-gateway <ip-address>
Switch(config-if)# no shutdown
To turn off automatic summarization, use the command,
router(config-router)#no
auto-summary
Please note that EIGRP automatically summarizes
routes at classful boundary (I.e. the network boundary), unless
otherwise specified.
To associate a switch with a management VLAN, you need to assign an IP address to the switch. The subnet portion of the switch IP address must match the subnet number of the management VLAN. Note that switches can maintain an IP stack, which enables us to manage the switches either locally, as well as remotely by Telnet.
51)Typically, a Cisco router has the following types of
memory components:
1. RAM (or DRAM): This type of memory
is used for working storage. This is where part of IOS image, routing
tables, packets, and others are stored during normal working of
a router. RAM is erased when the router is powered off.
2. ROM
(Read Only Memory): ROM stores bootstrap code for booting Cisco
IOS. It points to the functional IOS image so that the router can
complete its start-up configuration successfully. It is somewhat
analogous the BIOS in PC. ROM also contains a small portion of IOS.
3. Flash memory: Flash memory contains the fully functional IOS
images. It is the default location for getting IOS image at boot
time. You can loosely compare the IOS image with operating system
(say DOS).
4. NVRAM: NVRAM stands for Non Volatile RAM. NVRAM
stores the initial or startup configuration file.
VLAN port assignments can be configured either of two ways:
Static VLANs: The administrator statically configures VLAN port
assignment. VLAN memberships on the switch ports are assigned on
a port-by-port basis.
Dynamic VLANs: A VMPS (VLAN Management
Policy Server) can dynamically assign VLAN ports. The MAC address
of the node is used to determine the VLAN assignment. A separate
server or a Catalyst 5000 can function as a VMPS server. When a
frame arrives on a dynamic port at the switch, it queries the VMPS
for the VLAN assignment based on the source MAC address of the arriving
frame.