In this lesson,
we're going to discuss discovery protocols.
In today's complex network environments,
we have to understand and manage the myriad
of different connected devices
that we have on those networks.
By using discovery protocols,
like the Link Layer Discovery Protocol
and the Cisco Discovery Protocol,
we're going to be able to simplify this task for ourselves.
First, we have the Link Layer Discovery Protocol.
The Link Layer Discovery Protocol, also known as LLDP,
is an open standard protocol that was defined
in the IEEE 802.1ab standard,
and this open protocol allows devices on a network
to advertise themselves and discover the information
that there is about other devices,
and this promotes interoperability
across multiple different vendors.
Now, by using LLDP,
we're going to have essential details provided to us,
such as the device's identification, its capabilities,
its associated ports,
and this also offers network administrators
a clear view of the network topology
and can help us to achieve effective network management.
Now, the second protocol we have to talk about
is the Cisco Discovery Protocol.
Now, the Cisco Discovery Protocol, also known as CDP,
is a proprietary protocol developed by Cisco,
as its name implies,
and the CDP is going to provide similar functionalities
that we can use just like LLDP,
but the difference is they are specifically tailored
for use in Cisco-based environments,
including routing and switching devices
that were made by Cisco.
When you're dealing with the Cisco Discovery Protocol,
it's going to facilitate the collection
of detailed device information,
including things like model numbers,
IP addresses, connected interfaces,
and even the device's power consumption.
This information is much more detailed
and much more valuable to us
when we're operating in a Cisco-centric network
because we now have this proprietary protocol
that understands how to talk better to these devices
than the open source and non-proprietary LLDP.
Now, when you're using the CDP,
it's important to realize that the specifics of each device
can lead to a more optimized performance
and swifter troubleshooting for you,
which is why if you're running a Cisco network,
you'll probably want to use CDP over LLDP.
Now, both LLDP and CDP are considered instrumental
in maintaining an accurate and comprehensive inventory
of your network devices.
This is because this inventory
is not just going to be a list of connected devices,
but it's actually going to be a dynamic and updating
environment that provides a rich data set
with insights into how these devices are interconnected
and how data is flowing through our networks.
This kind of visibility is not just convenient for us,
but it's also necessary for us
to be able to ensure network security, network performance,
and network reliability over time.
Now, when it comes to security,
these two protocols do help us in quickly identifying
any kind of unauthorized devices or rogue devices
that may try to join our network.
By having a real-time view of our connected devices,
we're going to be able to spot any kind of anomalies
and then take immediate action,
which can then mitigate potential security threats
for us much more quickly.
Another great use for the information provided by LLDP
and CDP is to be able to conduct performance optimization.
When you're conducting performance optimization,
we have to understand our network structures first
because this allows for more informed decisions
regarding how we want to better segment our network,
how we want to conduct load balancing,
and how we want to set up our quality of service settings too.
Now, these protocols bring us lots of different benefits,
like I just said,
but they also require careful configuration and management.
If you have the incorrect settings or misinterpretations
of the data that you're receiving,
this can actually lead to network issues
or security vulnerabilities that could be exploited
by an attacker.
For example, if the Link Layer Discovery Protocol
or the Cisco Discovery Protocol information
is accessible over an unsecured port,
this can actually provide an attacker
with a roadmap of your entire network
and essentially conduct a reconnaissance for them.
Therefore, it's really important
that you implement these protocols
with a mindful approach that considers security
as well as your overall environment
to ensure that the information
is only available to authorized personnel
and authorized devices.
So remember, when it comes to LLDP and CDP,
these are more than just discovery protocols.
They're also foundational tools
for modern network management at scale.
By providing us with a detailed view
of the network's infrastructure,
these two protocols can empower us as network administrators
to better maintain, secure, and optimize our networks
more effectively.
As our networks continue to grow in size and complexity,
the role of these type of discovery protocols
in maintaining our network visibility and integrity
becomes only more significant.
So if you're using a multi-vendor environment,
you can use LLDP, or the Link Layer Discovery Protocol,
for this purpose.
But if you're using a Cisco-only network,
then you may want to opt to use CDP,
or the Cisco Discovery Protocol,
since it provides additional details and information
that you don't get with LLDP.