CCNA 21 to 41 Flashcards
ARIN
American Registry for Internet Numbers
ARIN is a nonprofit, member-based organization that administers IP addresses & ASNs in support of the operation and growth of the Internet.
DMVPN
Dynamic Multipoint VPN (DMVPN) is a Cisco IOS Software solution for building scalable IPsec Virtual Private Networks (VPNs). Cisco DMVPN uses a centralized architecture to provide easier implementation and management for deployments that require granular access controls for diverse user communities, including mobile workers, telecommuters, and extranet users.
DMVPN depends on two protocols
- MGRE- multi point generic routing encapsulation
- NHRP- Next hop resolution protocol
VLSM
Variable Length Subnet Masking–
“subnetting subnets,” which means that VLSM allows network engineers to divide an IP address space into a hierarchy of subnets of different sizes, making it possible to create subnets with very different host counts without wasting large numbers of addresses
CIDR
Classless Indomain Routing- Number of binary ones in the subnet mask
Route Summarization
a method where we create one summary route that represent multiple networks/subnets. It’s also called route aggregation or supernetting. Summarization has a number of advantages: Saves memory: routing tables will be smaller which reduces memory requirements
IPv6
“hexadecimal notation” layer 3 addressing (same as IPv4) with greater address range
16 binary bits in each “hextet”
first 4 “hextet” = network
last 4 “hextet” = host
only uses CIDR notation
loopback interface
test interface IPv4 and IPv6
Binary- 0000…0001
loopback address= ::1/128
enable
conf t
interface loopback “0”
IPv6 Address
“Call home”
Link local address
Binary 1111 1110 10… (first ten)
IPv6 FE80::/10
Used for only local network communication
Generated using the MAC address, sliding it down the middle and add FFFE to the middle then “flip a bit” (invert the 7th bit) the add FE80:: to the beginning :D
EUI-64
Routers use for neighbor access/ communication of routes since this address is more stable
(Non routable IPs)
equivalent to 169.254.0.0/16 address (self assigned with the device is not able to obtain an address)
Can also have randomly assigned host bits*
Unspecified Address
Binary- 0000…0000
IPv6- ::/ 128
“I don’t have an address”
The unspecified address (0:0:0:0:0:0:0:0 or ::) is used only to indicate the absence of an address. It is equivalent to the IPv4 unspecified address of 0.0.0.0. The unspecified address is typically used as a source address when a unique address has not yet been determined.
Multicast Address
Binary 1111 1111 … (first eight)
IPv6 FF00::/8
“Broadcast” / multicast groups “Radio Channel”
**1 to many
One address group that multiply devices join
**OSPF broadcast address 224.0.0.5
How do you shorten an IPV6 address ?
1) You can Drop Leading Zeros.
2) You can replace running groups of zeros (once)
Example:
IPV6:2001:0010:000A:1001:0051:0000:0000:ZA11
Shorten: 2001:10:A:1001:51::ZA11
Unicast Address
A unicast address is an address that is assigned to a single interface. Unicast addressing is available in IPv4 and IPv6 and typically refers to a single sender or a single receiver, although it can be used in both sending and receiving
There are three kinds of Unicast addresses:
Global Unicast, Link Local and Unique local address
EUI-64
Ability of IPv6 to address
is a method we can use to automatically configure IPv6 host addresses. An IPv6 device will use the MAC address of its interface to generate a unique 64-bit interface ID.
Unique Local Address
Private IPv6 addresses
FC00::/7
equivalent to 10.0.0.0/ 8 private addresses
DAD
Duplicate Address Detection
Basic Service Set (BSS) and BSSID
Basic Service Set
The Basic Service Set is a group of devices (computers, printers, tablets) that communicate together within an 802.11 / wireless network. The BSS may or may not include AP (Access Point) which provide a connection to a wire network.
BSSID is the Mac address for APs
Basic Service Area (BSA)
The physical area of coverage provided by an access point in a BSS is known as the basic service area (BSA)
SSID
Service Set ID - Name of the wireless network
BSSID
Basic service set ID- used to identifier different WAPs in the same wireless network. Devices us this on the back end to determine which WAP to connect too.
Mesh Network
Wireless access points that project wireless connection to each other.
One is usually connected to a hard wire connection and the rest connect to each other wirelessly.
Roaming
One a device moves between wireless access points based on signal connection strength.
RSSI
RSSI stands for Received Signal Strength Indicator. It is an estimated measure of power level that a RF client device is receiving from an access point or router. At larger distances, the signal gets weaker and the wireless data rates get slower, leading to a lower overall data throughput.
Trunked / Tagged Ports
Trunks carry the traffic of multiple VLANs over a single link and allow you to extend VLANs across the network.
802.1 Q TAG
The most common encapsulation method for VLAN tagging.
The process of modifying frames of data to include additional information. Add vlan tag to the frame.
Enable Conf t Interface fa0/1.10 Encapsulation dot1q 10 IP address x.x.x.x x.x.x.x
Access / Untagged Ports
An access port can have only one VLAN configured on the interface; it can carry traffic for only one VLAN.
Access Control List (ACL)
ACL is an ordered list of rules used to filter traffic. Each rule states what’s permitted or what’s denied. When a packet attempts to enter or leave a router, it’s tested against each rule in the list — from first to last. If the packet matches a rule, its outcome is determined by the conditions of the statement: If the first rule the packet matches is a permit statement, it’s permitted; if it’s a deny statement, it’s denied.
Extended Service Set (ESS)
Describes multiple WAPs broadcasting the same SSID
Router-on-a-stick (ROAS)
is a feature that allows us to route packets to subnets associated with VLANs connected to a router 802.1Q trunk. It uses a router VLAN trunking configuration to give the router a logical interface connected to each VLAN.
