Access Clause at Design used to be very challenging because we'd have a bunch
of independent
access switches.
We'd have to create some kind of redundancy here.
We'd have to make sure that we're connected upstream.
Maybe we'd connect it like it's in the diagram.
Maybe we'd try to create a loop through like this, but either way, again, we
have a lot
of challenges when the access switches are individual switches from one another
.
So we're asked to deploy technology that is going to kind of make things more WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
So we're asked to deploy technology that is going to kind of make things more
efficient
for us.
And so it starts by simplifying this access layer design, and we want to
leverage chassis
or stat switches.
So what this allows us to do is essentially combine all of these together into
a single
logical switch.
Now that could be either a chassis or a set of stackable switches.
Lot of network engineers have their preference.
Maybe you prefer one over the other.
Maybe you say, "Yeah, they're all the same to me. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
Maybe you say, "Yeah, they're all the same to me.
It doesn't really matter."
But either way, we would expect this now to be a single switch.
So we can get rid of this connection or call it maybe the stack cable now,
whatever it
is, but either way, it doesn't show up on our network topology diagram.
Now at this point, we still have STP blocking in place.
And so next, we're asked to simplify the distribution block with a technology.
Well, unfortunately, our network designs don't really promote turning this into
a stack, WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
a stack,
like one big stack.
We can't just say, "We don't need the second one.
We'll just create a stack."
And then we're good because if there's a control plane failure here or just
flat out the
whole switch reloads unintentionally or maybe even intentionally for
maintenance, it would
take down our entire distribution block.
We don't want to put all of the proverbial eggs in one basket.
So instead, what we do is we maintain two distinct logical switches.
But what we can do is we can combine, I said that wrong, two distinct physical WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
But what we can do is we can combine, I said that wrong, two distinct physical
switches,
but we combine them into one logical switch still.
And so by combining them into one logical switch, by having two distinct
physical switches,
this allows us to hopefully simplify the architecture.
Now what technology do we use to do this?
Well, it used to be known as VSS technology virtual switching system.
This would be on the old 6,500s and actually 6,800s and 4,500s as well. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
This would be on the old 6,500s and actually 6,800s and 4,500s as well.
But these days, on the nine case, we're going to call this stackwise virtual.
Same concept, we're going to combine two physical switches into one logical
switch.
So now we have one logical switch at the distribution layer.
We have one logical switch down here at the access layer.
And if we have one logical switch in both locations, we can now port channel
these two together,
which eliminates the third, the spanning tree protocol blocking, which is what WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
which eliminates the third, the spanning tree protocol blocking, which is what
the third
bullet point is asking us to do.
So I will say this is the beautiful architecture that we would love to deploy
to every single
access closet, if possible, so that our distribution switches operate in this
fashion.
But unfortunately, there are limitations.
For example, if there's a second switch down in the access closet, or if there
are access
closets that maybe we just have budgetary concerns or we have concerns around WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
closets that maybe we just have budgetary concerns or we have concerns around
stackwise
virtual, whatever the situation is, there will be limitations to this.
But if we can achieve this in our campus designs, it's going to greatly
simplify our topologies
from a spanning tree perspective.
And it's going to reduce the amount of broadcast storms and just general
network issues that
we have.
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