Now, if you want to use tracking technology, you need to buy the right switches, so essentially you
need to buy the right product for the feature that you want.
As mentioned, Cisco have supported stacking for a long time.
Such as,
such as the 3750 have supported stackwise for many years.
Here's some examples.
FlexStack was introduced in 2010.
FlexStack plus was introduced in 2013.
The switches that support FlexStack are the 2960s and 2960x for FlexStack
Plus you need a 2960x or 29
60xr. The speed of a single link in both directions
using full duplex is 10 gigabits per second for FlexStack and 20 gigabits per second for FlexStack
plus. The maximum number of switches supported in one stack is 4 for FlexStack and 8 for Flex
Stack
Plus. In the real world
have a look on the Cisco documentation and the data sheets for any switch that you want to buy to ensure
that it supports the speeds and capabilities that you need.
Now, Chassis aggregation is another Cisco technology which allows you to make multiple switches operate
as a single switch.
From a big picture perspective.
In a lot of cases, switch stacking is used after the access layer, whereas Chessie aggregation is
used for more powerful switches used in the distribution.
And Callejas.
So in summary, Chessie aggregation is used for high end switches.
As an example, Chessie based switches used in the distribution and Callejas of campus networks.
It does not require special hardware adapters, but rather uses Ethernet interfaces on switches.
It typically aggregates only two switches.
It's more complex to configure, but provides more options.
Now, from a big picture point of view, Chessie aggregation is the same as switch stacking.
Multiple switches act as one switch, which gives you both availability and design advantages.
However, one of the big reasons for Chessie based aggregation is high availability designs.
Technologies such as Cisco Virtual Switching System, or VSS is supported on the Cisco 6500 and 6800
series switches.
Have a look at Cisco's website for more details, but he has a quick overview.
Now, even if you're not using Chessie aggregation, you need high availability in the core and distribution
layer of your network.
As discussed, one of the reasons for having multiple switches in the distribution or KOLIA is to provide
redundancy in case one of those switches goes down.
So we use technology such as HSP, spanning tree and others to provide better redundancy and better
scalability.
However, the downside is cost.
You need additional switches and it's also more complex to configure.
You need to think about where you put your spending tree roots as well as your HSP active rodders.
Now, Chessie based switch typically has multiple line cords, one or more supervisor modules and one
or more power supplies for redundancy.
You want redundant power supplies, you want redundant supervisors and you want multiple line cords
in your Chessie.
The idea with supervisor modules is if one of the supervisors goes down, the other one can take over
the management of the switch.
A supervisor module is essentially the brain for the chassis based switch.
If you lose your supervisor, the switch will have no brain.
Hence you have redundant supervisor modules in your switch.
You have redundant power supplies in case there's a problem with one of the power supplies.
And in addition, you'll have multiple connections from your access layer to multiple line cords using
link aggregation to ensure that if one of the line cords goes down, the network can continue functioning
using the redundant line code.
Now, with chassis based aggregation, what we're doing is taking multiple chassis based switches and
using either related to a through ISO channel between multiple chassis based switches to provide better
redundancy and better throughput to the distribution core of the network.
I've discussed that in a lot of detail in the campus videos that make up this course.
What we can do is take that a step further.
And instead of using link aggregation between the chassis based switches with spanning three inches
or P, we make the chassis based switches appear to be a single switch in the model.
On the left, the two switches are independent of one another.
They run their own Mac address tables.
They run the own instance of spending three.
They essentially act totally independently of one another.
You configure two separate switches in this example and you configure them independently of each other
with an aggregated chassis environment.
However, the switches appear to be one switch to the rest of the network.
You can have multiple physical ports going to different physical switches, but you can aggregate them
together using multi chassis etha channel because a logically a one has two physical connections to
the same switch, even though physically it's to physical connections to different switches and the
different ways to implement this.
We can use multi chassis etha channel but use an active standby control plane where one of the pairs
acts as the switch for the control plane protocols.
So one of the switches is in control of spending Treva Etha channel up and running protocols.
But to take advantage of the fording power of the supervisor modules on both switches, we have active
active data planes related to fording and layer three forwarding is done by both switches.
The switches synchronize their macarius tables and routing tables to support the.
There's a single switch management plan, however, in other words, you manage both switches on the
active switch when you change the config of the active switch, that configuration is synchronized automatically
with the standby switch.
Now, you could take this a step further where you have an aggregated virtual switch and an aggregated
access switch.
Physically, we've got to two switches in the distribution layer, but by using Chessie aggregation,
they appear to be one switch to the axis layer.
We have four physical switches, but they appear to be a single virtual switch.
And then we can run eight physical ports in a single etha channel between the distribution layer and
access layer.
And in that case, we don't need spanning tree because even though physically we have six switches,
virtually, we only have two switches with one virtual cable between them.
As always, the caveats and things to be aware of when doing this.
But that's the ultimate vision of link aggregation with Chessie aggregation and switch stacking.
You're aggregating your physical distribution switches into one virtual switch and you're stacking your
access layer switches into one virtual switch.
The simplifies the network because you don't have to worry about optimizing spending tree and optimizing
HSP.
There's no need for HSP because we have one virtual aggregated switch.
We would still run spanning tree in case there are problems.
But from a spending tree point of view, both of these ports are falling because there's only one logical
cable between the two switches.
It really simplifies the management and configuration of a campus network.
So in summary, stacking technologies and Chessie aggregation technologies allow you to simplify the
management and configuration, as well as the forwarding of traffic in an Ethernet network.