- DTP – Dynamic Trunking Protocol
- Cisco proprietary
- Включен по умолчанию на многих свичах, режим разный
- Best practice (как и с VTP) – отключать DTP и настраивать вручную/средствами автоматизации
- DTP пакеты передаются по vlan 1 для ISL и по native vlan для 802.1q, даже если эти vlan не разрешены в trunk
Таблица согласования в зависимости от режима ПОРТА
CONFIG
Switch(config)#interface gigabitEthernet 3/0
Switch(config-if)#switchport nonegotiate
SHOW
Switch#show dtp
Global DTP information
Sending DTP Hello packets every 30 seconds
Dynamic Trunk timeout is 300 seconds
16 interfaces using DTP
Switch#show dtp interface gigabitEthernet 0/1
DTP information for GigabitEthernet0/1:
TOS/TAS/TNS: ACCESS/AUTO/ACCESS
TOT/TAT/TNT: NATIVE/NEGOTIATE/NATIVE
Neighbor address 1: 000000000000
Neighbor address 2: 000000000000
Hello timer expiration (sec/state): 27/RUNNING
Access timer expiration (sec/state): never/STOPPED
Negotiation timer expiration (sec/state): never/STOPPED
Multidrop timer expiration (sec/state): never/STOPPED
FSM state: S2:ACCESS
# times multi & trunk 0
Enabled: yes
In STP: no
Statistics
----------
0 packets received (0 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
82 packets output (82 good)
41 native, 41 software encap isl, 0 isl hardware native
0 output errors
0 trunk timeouts
1 link ups, last link up on Sun Feb 16 2020, 19:17:00
0 link downs
Switch#show interfaces trunk
Port Mode Encapsulation Status Native vlan
Gi3/0 on 802.1q trunking 1
Port Vlans allowed on trunk
Gi3/0 1-4094
Port Vlans allowed and active in management domain
Gi3/0 1
Port Vlans in spanning tree forwarding state and not pruned
Gi3/0 none
Switch#show interfaces gigabitEthernet 3/0 switchport
Name: Gi3/0
Switchport: Enabled
Administrative Mode: trunk
Operational Mode: trunk
Administrative Trunking Encapsulation: dot1q
Operational Trunking Encapsulation: dot1q
Negotiation of Trunking: On
Access Mode VLAN: 1 (default)
Trunking Native Mode VLAN: 1 (default)
Administrative Native VLAN tagging: enabled
Voice VLAN: none
Administrative private-vlan host-association: none
Administrative private-vlan mapping: none
Administrative private-vlan trunk native VLAN: none
Administrative private-vlan trunk Native VLAN tagging: enabled
Administrative private-vlan trunk encapsulation: dot1q
Administrative private-vlan trunk normal VLANs: none
Administrative private-vlan trunk associations: none
Administrative private-vlan trunk mappings: none
Operational private-vlan: none
Trunking VLANs Enabled: ALL
Pruning VLANs Enabled: 2-1001
Capture Mode Disabled
Capture VLANs Allowed: ALL
Protected: false
Appliance trust: none
Дамп
s2-s3.pcapng
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