More rapid spending is backward compatible with a little to one D and in the same way Rapide previous
t is compatible with previous t on switch 3.
These ports were converging quickly because we're using rapid spending tree between switch 1 2 and 3
but the links to switch for are stored using Peavey's.
So what you'll notice is it takes longer for those links to converge
show spanning tree as an example shows me that the ports are now forwarding but they've taken a lot
longer to converge than they would have with Reppert Peavey's cheat.
So once again on interface gigabit zero one all know port shows spanning tree.
We can already see that gigabit.
0 1 is the root port and is forwarding and gigabit 0 0 is an alternate port and is blocking However
other ports such as gigabit 0 2 and 0 3 are still learning.
So it's going to take time for these ports to move to the forwarding state.
You can see they have now moved to the forwarding state but that's because there is an older version
of spanning tree negotiated between switch three and switch for switch three once again is using Reppert
previous the switch for however
is using per villans spanning tree not rapid Peavey's T.
So triple is shown in the output whereas once again on switch 3 it's Rapide previous t.
So that is backward compatibility between rapid previous t and previous t.
But the convergence will be slow between rapid previous and previous TB because of backward compatibility
and within the previous part of your network let's have a look at the capture.
So this is on switch three as advertised to the hub.
And what you can see here is that the protocol used a spanning tree not rapid spending tree and that's
because switch three has negotiated to use spending tree with switch for not rapid spending tree.
So in the output once again it's spanning tree protocol not rapid spending tree protocol path cost route
identify and bridge identify are shown here but it's negotiated to use the older version of spending
tree even though this document is old.
It provides a great explanation of rapid spending tree or ADA to the one w and multiple spending tree
or ADA to that one yes you can find this document as part of the course or you can search in Google
as an example for the Cisco Avot network infrastructure this document explains the evolution of spending
tree and house spending tree has existed for a long time in an unchanged format that has been enhanced
through the use of rapid spending tree and multiple spending tree it a two to one.
Once again is the initial version of spending tree and was designed to stop loops in switched or bridged
networks.
It was very difficult to get fast convergence with Ada to 1 D.
One of the problems with Ada 3:01 D is that it uses time as supports go from blocking to listening to
learning to forwarding and that process can take 50 seconds.
When a port comes up as an example it goes from listening to learning to forwarding which takes 30 seconds.
Now Cisco enhanced it through one D in the 1990s by introducing uplink Foster backbone first and port
fust for the CCN course today.
You don't need to know about uplink fast or backbone fast.
You can just ignore those.
The important one to remember is port fast or ports which are ports connected to and a use of devices
such as PCs or servers that transition immediately to the forwarding state.
The trouble e incorporated most of these concepts into two standards.
Rapid spending tree and multiple spending tree with these protocols convergence time as were a lot quicker
Cisco have taken that those protocols and enhanced PV is ti.
So today we have Rapide previous to t and Cisco switches.
So as an example on the switch we can type spending tree mode and we can specify Reppert previous TTY
or MSCE the industry standard version of rapid spending tree only has one root in the entire topology
where as a Reppert Peavey's T gives you a route on a per villaine basis.
So it's a lot better than pure Reppert spending tree or editor one w multiple spending tree doesn't
give you a route per Villon but it gives you the ability to associate multiple villans to a spanning
tree root.
So you could say in a campus network as an example that villans 1 to 100.
So which one is the root.
But villans 101 to 200 have switched to as the root.