tdubb123
Expert
Expert

cisco trunk port config

Does anyone have a cisco trunk port config ? I am setting up vm network switch with 2 ports that will have a few vlans.

i am using VST

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5 Replies
Rubeck
Virtuoso
Virtuoso

interface GigabitEthernet1/1

description VMware ESX Trunk port

switchport trunk encapsulation dot1q

switchport trunk allowed vlan 5,10,11,130

switchport mode trunk

switchport nonegotiate

spanning-tree portfast trunk

/Rubeck

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tdubb123
Expert
Expert

hi

why do I need to enabled portfast on the trunk?

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benma
Hot Shot
Hot Shot

STP Portfast is a feature in Cisco IOS which allows a switchport which

is participating in STP to directly transition from Blocking mode to

Forwarding mode when a device connects and the link goes up.

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Rubeck
Virtuoso
Virtuoso

As vSwitches cant participate in a STP loop anyway, the port might as well start to forward right away..

From

Due to the specifics of VMware, the following design considerations apply:

Configure the switchport trunk for trunkfast (i.e., such that the port goes forwarding immediately without waiting for Spanning Tree timers).

/Rubeck

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tdubb123
Expert
Expert

we also have loopguard enabled. Its generating errors even with portfast enabled on the trunks. Should I disbale loopguard?

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