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An apology like this we had to configure spanning tree HAARP link aggregation and other technologies

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to try and optimize the way that this topology works as an example we made a switch one route for some

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of the lines and then we made switch to a route for other lands.

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So we managed to optimize a to forwarding by optimizing spending tree but then to optimize the routing

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in this topology we had to configure HSP and then configure switch one as the primary for the same lines

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as the as the root switch.

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In other words if switch one is the spending tree root or for veel and 10 then we had to make it to

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the SAPI primary router for villaine 10.

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So in other words we have to optimize both spending tree as well as HAARP to make sure that they are

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aligned.

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In other words if so which one is the spending tree root for veal and 10 we don't want to make a switch

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to the edges of the primary router for the last 10.

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We want to match them up to optimize the forwarding.

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So it's a lot of additional work that you need to do here.

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You need to configure spending.

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You need to configure your.

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You need to configure LINQ aggregation you've got to match it all up.

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It's not very efficient.

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Is there a better way of doing this.

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And fortunately the answer is yes there is a better way of doing this.

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I've done a search in Google for Cisco stacking images and you'll find many images such as the following

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showing you examples of Cisco switches being stacked.

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Now they are different technologies for doing this.

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In other words they are different to stacking technologies.

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One of the oldest is stuck wise which was used on the 30 750 switches.

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But again if you do a search in Google where you have a look at some of the Cisco documentation you'll

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see a lot of examples of different stacking technologies that can be used to stack the Cisco switches.

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So what's the advantage of stacking switches in this way.

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In brief when you stack switches they appear to be a single switch to the rest of the network.

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You configure it as a single switch.

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They act as a single switch protocol such as spending tree and CGP see that switch as a single switch.

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So again Cisco has various technologies that you can use to stack switches or aggregate shesays.

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So we have these terms switch stacking and chessy aggregation separate physical switches work together

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and cooperate together to act and appear as a single switch rather than multiple discrete switches.

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As an analogy it's as if the switches are acting as blades in a Chessie based switch switch.

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Stacking is often used at the Access Layer and chessy aggregation is often used at the distribution

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and coleus of a network.

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So if you've got multiple access layer switches or multiple distribution or coleus switches rather than

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you having to configure each switch individually and configure protocol such a spanning tree the CTP

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and so forth you configure multiple physical switches as if they one switch they have a mac address

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table.

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They run protocols as if they were a single switch and share a MAC Address table.

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So when you stack switches at the Access Layer you're literally creating a stack of switches and joined

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together via special cables.

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So a stack of physical switches in a wiring closet as an example can act as a single switch.

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You would manage the stack with a single management IP address.

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You would telnet or S-sh to one switch the one that has the management IP address and not have to tell

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only two or S-sh to multiple switches.

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There's one configuration file which is included across all the physical switches spanning tree CTP

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and VTB are running on one switch not on multiple switches the ports on each physical switch appear

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to be part of the same logical switch.

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In other words you may have four physical switches each having their own physical ports.

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But logically you've got one switch with all of those ports.

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There's one MAC Address table that references all the ports on all physical switches.

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There are some additional advantages but the moral of the story is you have a single virtual switch

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that you managing rather than four separate discrete switches.

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Now to connect the switches together you use special hardware ports called stacking ports.

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Again they are different Siska technologies.

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We've got as an example Cisco flex stack and flex stack plus spec'ing technology you would as an example

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insert a stacking module in each switch and then connect them with a stacking cable.

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Different technologies work on different switches.

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So Flex stack and flex stack plus all supported by 29 60 switches such as the 29 60 Yes 29 60 or 29

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60 x and 29 60 x or switch families 37 50 switches which are older switches support stack wise.

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Now what are these fucking cables.

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Do they form a ring between the switches.

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In other words the switches are connected in a series with a lost switch connected back to the first

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switch as shown in this topology by using full duplex on each link.

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The stacking modules and cables create two paths to force data between the physical switches in the

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stack the switches use these connections to communicate between the switches in the stack as well as

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to Ford frames and perform other overhead functions.