Usage
When you see this [[CISCO IOS CHEATSHEET#ipv6 unicast-routing |
this]]you only need to focus on the left most part before the # in this case. “CISCO
IOS CHEATSHEET”. Search for the name of the file with “CTRL+f” and type the name
this will bring you the the section that talks CISCO IOS CHEATSHEET. Alternatively use
the table of contents. I apologize in advance for the bad formatting as my notes were
originally written in Obsidian and this was the best I could do to convert everything.
MAC
A MAC address consists of 6 hexadecimal pairs of two.
00-1B-63-84-45-E6
The first 3 pairs are maintained by IEEE, and is called an organizationally unique identi-
fier (OUI).
[!info] IEEE and OUI Before someone can sell any Ethernet interface they
must register with IEEE in order to get an OUI. It is not allowed for you to
create your own OUI.
[!info] MAC multicast addresses always begin with 01-00-5E # Reliable net-
works Networks are widely used in everyday life. Which means it needs to
be reliable. There are four metrics to measure network reliability.
Fault Tolerance
When a network does fail, the number of affected devices must be limited. This way not
everyone is denied the services they are requesting for.
Related: https://duckduckgo.com/?q=packet+switching+net-
work&t=newext&atb=v326-1&ia=about
Scalability
A scalable network can expand quickly and easily to support new users and applications
without impacting existing users.
Quality of service (QoS)
QoS is the primary policy used to ensure reliable delivery of content for all users. Which
allows the router to manage the flow of data easily.
OSI
OSI is made by ISO (International Organization for Standardization) and ITU (Interna-
tional Telecommunications Union). OSI includes a seven layer model called the OSI ref-
erence model. But, has been replaced by [Transmission Control Protocol]
OSI Reference Model
You look at this bottom to top. So Layer 1 is physical layer, Layer 2 is [Data link layer].
1
,Every layer will perform [Data Encapsulation] and de-encapsulation.
1. Application. Contains protocols used for process-to-process communications.
2. Presentation. Provides for common representation of the data transferred between
application layer services.
3. Session. Provides services to segment, transfer and reassemble the data for individ-
ual communications.
4. Transport. The network protocol. A network protocol is in charge of delivery your
data reliably.
5. Network. Handles addressing, routing. Provides services to exchange the individ-
ual pieces of data over the network. These services will determine which route a
packet will take in order to reach its destination.
6. Data link. Handles error detection, and routing. Describes methods for exchanging
data frames over a common media.
7. Physical layer. It describes how data is sent from one location to another. Through
fiber optic cables, wireless, etc.
IPv6 Multicast
[[IPv6]] has it’s own version of [Multicast] but it functions the same way. Just like in
[[IPv6 Unicast]] it has two types of multicast addresses. All IPv6 multicast addresses
have the prefix ff00::/8.
Well-known
Well-known [[IPv6 Unicast]] multicast addresses are reserved for different groups. Since
it is reserved, it cannot be changed.
All-nodes mulitcast group
Has ff02::1. This is a group that is sent to all IPv6 enabled devices excluding routers.
All-routers multicast group
Has ff02::2. This group is joined by all IPv6 routers. Routers will join this group
when it is enabled as an IPv6 router. A router can be enabled as IPv6 with [[CISCO IOS
CHEATSHEET#ipv6 unicast-routing | this]] command.
Solicited node
This multicast type is used to detect if there an [[IPv6]] that is currently used in the [[IPv6
Unicast#^9c43ef | LLA]] of another device. This is helpful when an IPv6 address is be-
ing assigned automatically with DCHPv6, to ensure there aren’t any duplicates. The is
process is called duplicate address detection (DAD). # Types of cloud computing ## Pub-
lic clouds Available to the general public through a pay-per-use model or for free. The
only downside is that it may not be the most secure. As you don’t really know if an em-
ployee behind the cloud service might take a peek at your files.
Private clouds
Private clouds as the name suggests private. Businesses tend to setup up their own cloud
to provide security for company data. It is quite costly as the cloud needs to be up 24/7
and that costs electricity. Although, it is a lot more customizable.
2
,Hybrid cloud
It’s a hybrid of public and private clouds. It has the advantages of both public and pri-
vate clouds. The disadvantage is that there may be a lot of problems at the network level.
Frame
A frame (or Ethernet frame) is a protocol data unit of the [Data link layer]. Packets from
the [[Network Access Layer]] are converted into frames via the process of [Data Encapsu-
lation].
[!note] The term “packet” is sometimes also used in place of “frame”. They’re
used interchangeably.
Powerline networking
Physical Layer
The physical layer is part of [[Transmission Control Protocol | TCP-IP]] and [[OSI |
OSI]]. It involves hardware such as NICs, routers, switches, cables such as [[Copper Ca-
bling]], etc. Before data is sent to other devices it is converted to a relevant format this
process is called encoding. This is the final step in [Data Encapsulation] and produces a
[Frame].
Different mediums will have the data converted to different signals. Fibre optic cabl
Port Number Groups
There are 65536 ports, from 0 to 65535. The Internet Assigned Numbers Authority
(IANA) is the standards organization for assigning the 16 bit port numbers. The port
groups are divided into 3 categories.
[!fig]+ Port groups
[!fig]+ Well-known port numbers # Network protocol functions 1. [[Reliable
networks]] 2. [[Protocols#^0f8263 | Flow control]] 3. [[Data Encapsula-
tion#Sequencing | Sequencing]] 4. [[Transmission Control Protocol#^c4d6aa
| Error detection]] 5. Application interface. This function contains informa-
tion used for process-to-process communications between network applica-
tions. For example, when accessing a web page, HTTP or HTTPS protocols
are used to communicate between the client and server web processes. # IPv6
packet
Bandwidth
Bandwidth refers to the amount of data that can flow in a second. It also refers to the ca-
pacity at which a medium can carry data.
Related terminology
• Latency. Amount of time including delays for data to travel from one point to an-
other.
• Throughput
3
, • Goodput. The amount of usable data. Goodput = Throughput − Network overhead.
# IPv4 Addressing An IP is split into 2 portions. Network and host.
192. 162. 10. 5
192. 162. 10 represents a network id. All devices in the finance department might have
the same numbers for the network portion of their IP.
5 is the host. Which is the specific device in the network. Perhaps your PC has the host
at 5 and your co-worker’s is 20.
Incrementing
This is the way an IPv4 increments. If the current IP is 172. 29. 0. 254, the next IP would
be 172. 29. 0. 255 the next is 172. 29. 1. 0. Since the maximum is 255, it must reset to 0 and
the next value is incremented by one. So for 129. 29. 255. 255 the next IP is 129. 30. 0. 0
Subnet mask
A subnet mask helps to identify which network a device belongs to.
255. 255. 255. 0
192. 162. 10. 5
Wherever there is a number in the subnet mask. Represents which part is the network
for the IP address. In this example the network id is 192. 162. 10 The network id is used
to show which network a device belongs to. Like a family name.
Given the following [[Subnets#Subnet mask | Subnet mask]] $255.0.0.0$ The network ID
Transmission modes
There are three transmission modes 1. Simplex 2. Half duplex 3. Full duplex (or duplex)
Regardless of which transmission mode is chosen different modes are not compatible
with each other. Switches are able to communicate with other switches or devices, only
allowing a connection between switches or other devices that share the same transmis-
sion mode as itself.
Simplex
Data can only move one way.
Keyboards are a good example. It only sends inputs from the user. It doesn't accept a
Half duplex
In half duplex mode a device can transmit and receive data as well. But not at the same
time. If the device is transmitting data it can only do that. If it wants to receive data it
has to finish transmitting data first.
Like a walkie-talkie. One person speaks while the other listens. Only when one person
Pros & Cons
Both devices can send and receive data and the entire bandwidth is used specifically for
either one. However, when one device is sending data the other has to wait. Since the
4
When you see this [[CISCO IOS CHEATSHEET#ipv6 unicast-routing |
this]]you only need to focus on the left most part before the # in this case. “CISCO
IOS CHEATSHEET”. Search for the name of the file with “CTRL+f” and type the name
this will bring you the the section that talks CISCO IOS CHEATSHEET. Alternatively use
the table of contents. I apologize in advance for the bad formatting as my notes were
originally written in Obsidian and this was the best I could do to convert everything.
MAC
A MAC address consists of 6 hexadecimal pairs of two.
00-1B-63-84-45-E6
The first 3 pairs are maintained by IEEE, and is called an organizationally unique identi-
fier (OUI).
[!info] IEEE and OUI Before someone can sell any Ethernet interface they
must register with IEEE in order to get an OUI. It is not allowed for you to
create your own OUI.
[!info] MAC multicast addresses always begin with 01-00-5E # Reliable net-
works Networks are widely used in everyday life. Which means it needs to
be reliable. There are four metrics to measure network reliability.
Fault Tolerance
When a network does fail, the number of affected devices must be limited. This way not
everyone is denied the services they are requesting for.
Related: https://duckduckgo.com/?q=packet+switching+net-
work&t=newext&atb=v326-1&ia=about
Scalability
A scalable network can expand quickly and easily to support new users and applications
without impacting existing users.
Quality of service (QoS)
QoS is the primary policy used to ensure reliable delivery of content for all users. Which
allows the router to manage the flow of data easily.
OSI
OSI is made by ISO (International Organization for Standardization) and ITU (Interna-
tional Telecommunications Union). OSI includes a seven layer model called the OSI ref-
erence model. But, has been replaced by [Transmission Control Protocol]
OSI Reference Model
You look at this bottom to top. So Layer 1 is physical layer, Layer 2 is [Data link layer].
1
,Every layer will perform [Data Encapsulation] and de-encapsulation.
1. Application. Contains protocols used for process-to-process communications.
2. Presentation. Provides for common representation of the data transferred between
application layer services.
3. Session. Provides services to segment, transfer and reassemble the data for individ-
ual communications.
4. Transport. The network protocol. A network protocol is in charge of delivery your
data reliably.
5. Network. Handles addressing, routing. Provides services to exchange the individ-
ual pieces of data over the network. These services will determine which route a
packet will take in order to reach its destination.
6. Data link. Handles error detection, and routing. Describes methods for exchanging
data frames over a common media.
7. Physical layer. It describes how data is sent from one location to another. Through
fiber optic cables, wireless, etc.
IPv6 Multicast
[[IPv6]] has it’s own version of [Multicast] but it functions the same way. Just like in
[[IPv6 Unicast]] it has two types of multicast addresses. All IPv6 multicast addresses
have the prefix ff00::/8.
Well-known
Well-known [[IPv6 Unicast]] multicast addresses are reserved for different groups. Since
it is reserved, it cannot be changed.
All-nodes mulitcast group
Has ff02::1. This is a group that is sent to all IPv6 enabled devices excluding routers.
All-routers multicast group
Has ff02::2. This group is joined by all IPv6 routers. Routers will join this group
when it is enabled as an IPv6 router. A router can be enabled as IPv6 with [[CISCO IOS
CHEATSHEET#ipv6 unicast-routing | this]] command.
Solicited node
This multicast type is used to detect if there an [[IPv6]] that is currently used in the [[IPv6
Unicast#^9c43ef | LLA]] of another device. This is helpful when an IPv6 address is be-
ing assigned automatically with DCHPv6, to ensure there aren’t any duplicates. The is
process is called duplicate address detection (DAD). # Types of cloud computing ## Pub-
lic clouds Available to the general public through a pay-per-use model or for free. The
only downside is that it may not be the most secure. As you don’t really know if an em-
ployee behind the cloud service might take a peek at your files.
Private clouds
Private clouds as the name suggests private. Businesses tend to setup up their own cloud
to provide security for company data. It is quite costly as the cloud needs to be up 24/7
and that costs electricity. Although, it is a lot more customizable.
2
,Hybrid cloud
It’s a hybrid of public and private clouds. It has the advantages of both public and pri-
vate clouds. The disadvantage is that there may be a lot of problems at the network level.
Frame
A frame (or Ethernet frame) is a protocol data unit of the [Data link layer]. Packets from
the [[Network Access Layer]] are converted into frames via the process of [Data Encapsu-
lation].
[!note] The term “packet” is sometimes also used in place of “frame”. They’re
used interchangeably.
Powerline networking
Physical Layer
The physical layer is part of [[Transmission Control Protocol | TCP-IP]] and [[OSI |
OSI]]. It involves hardware such as NICs, routers, switches, cables such as [[Copper Ca-
bling]], etc. Before data is sent to other devices it is converted to a relevant format this
process is called encoding. This is the final step in [Data Encapsulation] and produces a
[Frame].
Different mediums will have the data converted to different signals. Fibre optic cabl
Port Number Groups
There are 65536 ports, from 0 to 65535. The Internet Assigned Numbers Authority
(IANA) is the standards organization for assigning the 16 bit port numbers. The port
groups are divided into 3 categories.
[!fig]+ Port groups
[!fig]+ Well-known port numbers # Network protocol functions 1. [[Reliable
networks]] 2. [[Protocols#^0f8263 | Flow control]] 3. [[Data Encapsula-
tion#Sequencing | Sequencing]] 4. [[Transmission Control Protocol#^c4d6aa
| Error detection]] 5. Application interface. This function contains informa-
tion used for process-to-process communications between network applica-
tions. For example, when accessing a web page, HTTP or HTTPS protocols
are used to communicate between the client and server web processes. # IPv6
packet
Bandwidth
Bandwidth refers to the amount of data that can flow in a second. It also refers to the ca-
pacity at which a medium can carry data.
Related terminology
• Latency. Amount of time including delays for data to travel from one point to an-
other.
• Throughput
3
, • Goodput. The amount of usable data. Goodput = Throughput − Network overhead.
# IPv4 Addressing An IP is split into 2 portions. Network and host.
192. 162. 10. 5
192. 162. 10 represents a network id. All devices in the finance department might have
the same numbers for the network portion of their IP.
5 is the host. Which is the specific device in the network. Perhaps your PC has the host
at 5 and your co-worker’s is 20.
Incrementing
This is the way an IPv4 increments. If the current IP is 172. 29. 0. 254, the next IP would
be 172. 29. 0. 255 the next is 172. 29. 1. 0. Since the maximum is 255, it must reset to 0 and
the next value is incremented by one. So for 129. 29. 255. 255 the next IP is 129. 30. 0. 0
Subnet mask
A subnet mask helps to identify which network a device belongs to.
255. 255. 255. 0
192. 162. 10. 5
Wherever there is a number in the subnet mask. Represents which part is the network
for the IP address. In this example the network id is 192. 162. 10 The network id is used
to show which network a device belongs to. Like a family name.
Given the following [[Subnets#Subnet mask | Subnet mask]] $255.0.0.0$ The network ID
Transmission modes
There are three transmission modes 1. Simplex 2. Half duplex 3. Full duplex (or duplex)
Regardless of which transmission mode is chosen different modes are not compatible
with each other. Switches are able to communicate with other switches or devices, only
allowing a connection between switches or other devices that share the same transmis-
sion mode as itself.
Simplex
Data can only move one way.
Keyboards are a good example. It only sends inputs from the user. It doesn't accept a
Half duplex
In half duplex mode a device can transmit and receive data as well. But not at the same
time. If the device is transmitting data it can only do that. If it wants to receive data it
has to finish transmitting data first.
Like a walkie-talkie. One person speaks while the other listens. Only when one person
Pros & Cons
Both devices can send and receive data and the entire bandwidth is used specifically for
either one. However, when one device is sending data the other has to wait. Since the
4
