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stp,auto negotiation, dtp, pagp which will run first on a port

sarahr202
Level 5
Level 5

Hi everybody.

How is everybody doing?

let say we have  ports on two switches as shown below, with all  these protocol configured : stp,auto negotiation,dtp,pagp

sw1-----------------------------sw2

Which protocol wil run first?

Let say we have another switch configured with stp,auto negotiation dtp lacp

Now we connect this switch to a server as shown below:

sw--------server

which protocol will run first ?

You guys have a great weekend.

1 Accepted Solution

Accepted Solutions

bonnardopjl
Level 1
Level 1

For sure, if "autonegotiation" is active, it will take place first.

It is necessary to decide first about the speed and half/full duplex, before doing anything else.

Next one is DTP, if active.

Please note that "autonegociation" is not active by default on any interface.

For 10/100/1000 interfaces, autonegociation is active by default,

In the normalization text, it is mandatory for RJ45 GE interfaces.

View solution in original post

3 Replies 3

gaurav bhardwaj
Level 1
Level 1

Q 1 first we run auto negotiation ,because dtp is default configure and stp is already run by default

Q 2  if it is layer 2 switch so there is no need to rn any protocol stp and dtp is default

Thanks Bharwaj.

My question was which protocol will run first?  I understand  dtp,auto negotiation and STP are on by default.  PAgp is on by default on CatOS switches as well.

I know between pAgp and STP, Pagp runs first.

thanks

bonnardopjl
Level 1
Level 1

For sure, if "autonegotiation" is active, it will take place first.

It is necessary to decide first about the speed and half/full duplex, before doing anything else.

Next one is DTP, if active.

Please note that "autonegociation" is not active by default on any interface.

For 10/100/1000 interfaces, autonegociation is active by default,

In the normalization text, it is mandatory for RJ45 GE interfaces.

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