■
DTP（Dynamic Trunking Protocol）とは、接続先のポートとネゴシエーションして、ポートの動作モードを決定するCisco独自のプロトコルです。
互いのポート同士がdynamic desirableモードに設定されていた場合は、ネゴシエーションの結果に関わらずtrunkモードとして動作します。
今回はスタティックでのtrunkの設定はしていません。
スタティックaccessで設定したfa0/1はネゴシエーションの結果に関わらずaccessモードとして動作します。
なので、このポートはネゴシエーションフレームを送信する必要がありません。
nonegotiateコマンドを設定してネゴシエーションフレームを無効にしています。
それによって帯域幅を無駄に使うことがなくなります。
またfa0/2はdynamic autoで設定したのですが、ポートの先にはパソコンが接続されているので、accessモードとして動作しています。
ちなみにポートの先がパソコンではなく、スイッチが接続されていて、尚且つtrunkモードやdynamic desirableモードであった場合は、trunkモードとして動作します。
以下、設定です。
―S1とS2の各fa0/1をaccessモードに設定
―S1とS2の各fa0/1からDTPのネゴシエーションフレームを送信しないように設定
―S1とS2の各fa0/2をdynamic autoモードに設定
―S1とS2の各fa0/12をdynamic desirableモードに設定
■S1
S1(config)#vlan 10
S1(config-vlan)#name VLAN_10
S1(config-vlan)#exit
S1(config)#vlan 20
S1(config-vlan)#name VLAN_20
S1(config-vlan)#exit
S1(config)#int fa0/1
S1(config-if)#switchport mode access←accessモード
S1(config-if)#switchport access vlan 10
S1(config-if)#switchport nonegotiate←DTPのネゴシエーションフレームを送信しない
S1(config-if)#int fa0/2
S1(config-if)#switchport mode dynamic auto←dynamic autoモード
S1(config-if)#switchport access vlan 20
S1(config-if)#int fa0/12
S1(config-if)#switchport mode dynamic desirable←dynamic desirableモード
S1#sh int fa0/1 switchport
Name: Fa0/1
Switchport: Enabled
Administrative Mode: static access
Operational Mode: static access
Administrative Trunking Encapsulation: dot1q
Operational Trunking Encapsulation: native
Negotiation of Trunking: Off
Access Mode VLAN: 10 (VLAN_10)
Trunking Native Mode VLAN: 1 (default)
Voice VLAN: none
Administrative private-vlan host-association: none
Administrative private-vlan mapping: none
Operational private-vlan: none
Trunking VLANs Enabled: ALL
Pruning VLANs Enabled: 2-1001
Capture Mode Disabled
Capture VLANs Allowed: ALL
Protected: false
Voice VLAN: none (Inactive)
Appliance trust: none
S1#sh int fa0/2 switchport
Name: Fa0/2
Switchport: Enabled
Administrative Mode: dynamic auto
Operational Mode: static access
Administrative Trunking Encapsulation: dot1q
Operational Trunking Encapsulation: native
Negotiation of Trunking: On
Access Mode VLAN: 20 (VLAN_20)
Trunking Native Mode VLAN: 1 (default)
Voice VLAN: none
Administrative private-vlan host-association: none
Administrative private-vlan mapping: none
Operational private-vlan: none
Trunking VLANs Enabled: ALL
Pruning VLANs Enabled: 2-1001
Capture Mode Disabled
Capture VLANs Allowed: ALL
Protected: false
Voice VLAN: none (Inactive)
Appliance trust: none
S1#sh int fa0/12 switchport
Name: Fa0/12
Switchport: Enabled
Administrative Mode: dynamic desirable
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)
Voice VLAN: none
Administrative private-vlan host-association: none
Administrative private-vlan mapping: none
Operational private-vlan: none
Trunking VLANs Enabled: ALL
Pruning VLANs Enabled: 2-1001
Capture Mode Disabled
Capture VLANs Allowed: ALL
Protected: false
Voice VLAN: none (Inactive)
Appliance trust: none
■S2
S2(config)#vlan 10
S2(config-vlan)#name VLAN_10
S2(config-vlan)#exit
S2(config)#vlan 20
S2(config-vlan)#name VLAN_20
S2(config-vlan)#exit
S2(config)#int fa0/1
S2(config-if)#switchport mode access←accessモード
S2(config-if)#switchport access vlan 10
S2(config-if)#switchport nonegotiate←DTPのネゴシエーションフレームを送信しない
S2(config-if)#int fa0/2
S2(config-if)#switchport mode dynamic auto←dynamic autoモード
S2(config-if)#switchport access vlan 20
S2(config-if)#int fa0/12
S2(config-if)#switchport mode dynamic desirable←dynamic desirableモード
S2#sh int fa0/1 switchport
Name: Fa0/1
Switchport: Enabled
Administrative Mode: static access
Operational Mode: static access
Administrative Trunking Encapsulation: dot1q
Operational Trunking Encapsulation: native
Negotiation of Trunking: Off
Access Mode VLAN: 10 (VLAN_10)
Trunking Native Mode VLAN: 1 (default)
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 encapsulation: dot1q
Administrative private-vlan trunk normal VLANs: none
Administrative private-vlan trunk private VLANs: 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
S2#sh int fa0/2 switchport
Name: Fa0/2
Switchport: Enabled
Administrative Mode: dynamic auto
Operational Mode: static access
Administrative Trunking Encapsulation: dot1q
Operational Trunking Encapsulation: native
Negotiation of Trunking: On
Access Mode VLAN: 20 (VLAN_20)
Trunking Native Mode VLAN: 1 (default)
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 encapsulation: dot1q
Administrative private-vlan trunk normal VLANs: none
Administrative private-vlan trunk private VLANs: 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
S2#sh int fa0/12 switchport
Name: Fa0/12
Switchport: Enabled
Administrative Mode: dynamic desirable
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)
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 encapsulation: dot1q
Administrative private-vlan trunk normal VLANs: none
Administrative private-vlan trunk private VLANs: 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
■192.168.0.100から192.168.0.200にping
C:\Documents and Settings\192.168.0.100>ping 192.168.0.200
Pinging 192.168.0.200 with 32 bytes of data:
Reply from 192.168.0.200: bytes=32 time=1ms TTL=128
Reply from 192.168.0.200: bytes=32 time=1ms TTL=128
Reply from 192.168.0.200: bytes=32 time=1ms TTL=128
Reply from 192.168.0.200: bytes=32 time=1ms TTL=128
Ping statistics for 192.168.0.200:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 1ms, Maximum = 1ms, Average = 1ms
■192.168.1.100から192.168.1.200にping
C:\Documents and Settings\192.168.1.100>ping 192.168.1.200
Pinging 192.168.1.200 with 32 bytes of data:
Reply from 192.168.1.200: bytes=32 time=1ms TTL=128
Reply from 192.168.1.200: bytes=32 time=1ms TTL=128
Reply from 192.168.1.200: bytes=32 time=1ms TTL=128
Reply from 192.168.1.200: bytes=32 time=1ms TTL=128
Ping statistics for 192.168.1.200:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 1ms, Maximum = 1ms, Average = 1ms
