what does this means (DTP)

Unanswered Question
Sep 21st, 2007
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SW1#show DTP interface

DTP information for GigabitEthernet2/1:


TOT/TAT/TNT: 802.1Q/802.1Q/802.1Q

Neighbor address 1: 000B5F418D46

Neighbor address 2: 000000000000

Hello timer expiration (sec/state): 15/RUNNING

Access timer expiration (sec/state): 286/RUNNING

Negotiation timer expiration (sec/state): never/STOPPED

Multidrop timer expiration (sec/state): never/STOPPED

FSM state: S6:TRUNK

# times multi & trunk 0

Enabled: yes

In STP: no



334587 packets received (334587 good)

0 packets dropped

0 nonegotiate, 0 bad version, 0 domain mismatches,

0 bad TLVs, 0 bad TAS, 0 bad TAT, 0 bad TOT, 0 other

334595 packets output (334595 good)

334592 native, 3 software encap isl, 0 isl hardware native

0 output errors

0 trunk timeouts

3 link ups, last link up on Mon May 28 2007, 10:18:09

2 link downs, last link down on Mon May 28 2007, 10:15:32

What does these two statements mean


TOT/TAT/TNT: 802.1Q/802.1Q/802.1Q

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Kevin Dorrell Fri, 09/21/2007 - 06:48
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This is an educated guess:

TOS = Trunk Operational Status

TAS = Trunk Administrative Status

TNS = Trunk Negotiated Status

TOT = Trunk Operational Trunk-Encapsulation

TAT = Trunk Admnistrative Trunk-Encapsulation

TNT = Tunk Negotiated Trunk-Encapsulation

Operational = What we are doing at this moment

Administrative = How we configured it

Negotiated = What we asked for during the negotiation

Kevin Dorrell


Richard Burts Fri, 09/21/2007 - 07:02
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Well DTP is Dynamic Trunking Protocol. I can find quite a few examples of the show dtp interface command which include the output lines that you ask about. But I am not finding an official explanation for these lines.

Pretty obviously the first line is about the trunking status and the second line is about trunking encapsulation. My guess is that the three fields in each line indicate how it is configured on the local device, how it is configured on the neighbor device, and what the result is after negotiation. So the TOS/TAS/TNS shows that it is configured as trunk on the local interface, configured as desirable on the neighbor, and results in trunk after negotiation. And both switches were set for dot1Q encapsulation.




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