CCNA2 Flashcards
RAM to store
IOS (copied to RAM during bootup) Running config Routing table ARP cache Packet buffer (IRRAP - Please Ask Indian Red Rabbit)
ROM to store
Bootstrap
Diagnostic software
Scaled-down version of IOS
Flash
Permanent storage for IOS
Can be upgraded
Default value of configuration register
0x2102
Command to show routing table on PC
route print
Metrics for dynamic routing protocols
Hop count, bandwidth, load, delay, reilability, cost
HBLDRC - Hello Baby, Let Dady Remove Caca
RIP: Hop count
OSPF: Bandwidth
EIGRP: combination of bandwidth and delay
Which routing protocol supports unequal cost load balancing
only EIGRP
Show command for CDP
show cdp neighbors [detail]
Command to disable CDP
(config)#no cdp run
Command to stop CDP advertisement on a interface
(config-if)# no cdp enable
To configure static route between Ethernet interfaces
always using exit interface together with next hop ip address
Distance vector routing protocols
RIP, EIGRP
AD of Connected, Static, EIGRP summary, Internal EIGRP, OSPF, RIP
0,1,5,90,110,120
RIP routing updates interval
30s
EIGRP
cisco proprietary
support unequal cost load balancing
uses DUAL
no peirodic updates, only update if thiere is a change, bounded update
RIP timers
Invalid 180s
Flush 240s
Holddown 180s
Radom Jitter
Collison caused by multiple route updates trasmited at the same time
RIP_JITTER: 0% to 15% of the interval.
Maximum metric in RIP
15 hops
Load balancing on RIPv1
Default load balancing is 4 equal cost paths, can support up to six paths.
Routes update addresses used by RIP
RIPv1 uses broadcast addresses, RIPv2 uses multicast addresses
Which routing protocol runs only on CISCO routers
EIGRP
EIGRP uses what to maintain all the routes received from neighbors
Use a Topology table
EIGRP uses what to establish adjacencies with neighboring routers
using hello protocol
EIGRP metric is based on
based on minimum bandwidth and cumulative delay of the path
EIGRP has fast convergence due to
DUAL calculation
EIGRP supports multiple network layer protocols such as
IP, IPX and AppleTalk
Class A IP addresses
Class A: 1.0.0.0 to 126.255.255.255
Class B IP addresses
Class B: 128.0.0.0 to 191.255.255.255
Class C IP addresses
Class C: 192.0.0.0 to 223.255.255.255
Configure RIPv1
#router rip (config-router)#network 192.168.4.0 (config-router)#network 192.168.5.0 (config-router)#passive-interface f0/0 (config-router)#default-information originate
Enhancements of RIPv2 to RIPv1
Next-hop addresses included in the routing updates
Use of multicast addresses in sending updates
Authentication option available
Two extensions are added in RIPv2 message:
- Subnet mask field
2. Next Hop address
Why use Null Interfaces
a static route must have an active exit interface before it will be installed in the routing table. Using the null interface will allow R2 to advertise the static route in RIP even though networks belonging to the summary 192.168.0.0/16 do not actually exist.
Command to configure Null Interfaces
R2(config)#ip route 192.168.0.0 255.255.0.0 Null0
RIPv2 command to populate static route
R2(config-router)#redistribute static
Command to enable RIPv2
(config)#router rip
(config-router)#version 2
Disable auto-summary on RIPv2
(config-router)#no auto-summary
What is A level 1 route
A level 1 route is a route with a subnet mask equal to or less than the classful mask of the network address
A level 1 route can function as:
Default route, supernet route, network route
What is an ultimate route
An ultimate route is a route that includes:
either a next-hop IP address (another path)
and/or an exit interface
What is A level 1 parent route
A level 1 parent route is a network route that does not contain a next-hop IP address or exit interface for any network.
Ex: 172.16.0.0/24 is subnetted, 1 subnets
What is A level 2 route
A level 2 route is a route that is a subnet of a classful network address.
C 172.16.3.0 is directly connected, FastEthernet0/0
Classful and classless routing behavior
Classful: (config)#no ip classless
Classless: (config)#ip classless
Purpose of Classful and classless routing behaviors
Classful and classless routing behaviors determine how the routing table is searched after it is populated.
EIGRP updates MAC address and IP address
Multicast, MAC: 01-00-5E-00-00-0A
IP: 224.0.0.10
EIGRP Packet Types
5 types: Hello | Update | Ack | Query | Reply
EIGRP Hello packets interval
5s on most networks, but 60s on NBMA such as Frame Relay, X.25 and ATM
EIGRP holdtime interval
3 times of the hello interval, which means 15s on most networks, and 180s on NBMA networks.
When will EIGRP ack packet be sent
When reliable delivery is used, ack packet always sent as unicst.
Which routing protocols can be configured to encrypt and authenticate their routing information?
RIPv2, EIGRP, OSPF, IS-IS, and BGP
What is the protocol used by EIGRP for the delivery and reception of EIGRP packets
Reliable Transport Protocol (RTP)
In order to establish neighbor adjacencies, EIGRP requires all routers in the same routing domain to be configured with the same…
process ID
EIGRP automatically includes a null0 summary route as a child route whenever both of following conditions exist:
There is at least one subnet that was learned via EIGRP.
Automatic summarization is enabled.
The default K values can be changed with the EIGRP router command:
Router(config-router)#metric weights tos k1 k2 k3 k4 k5
To verify k values
show ip protocols