Provided answer is correct.
Since there are multiple VLANs on the port, the port is in trunk mode. If you leave the trunk keyword (answer C), the following message is shown:
%Portfast has been configured on GigabitEthernet0/10 but will only
have effect when the interface is in a non-trunking mode.
Answer is C.
All ports have a p2p edge status. Edge indicates that they are connected to a host, not a switch.
If the status would be p2p, they would be a trunkport. In which case, spanning-tree portfast trunk could be used.
Quote from Ciscopress ENCOR 350-401 book, page 66:
"The portfast feature is enabled on a specific access port with the command spanning-tree portfast or globally on all access ports with the command spanning-tree portfast default."
I'm saying answer is A. Reason is a trunk port can go to a client and doesn't have to go to a switch. As it's a trunk, the word 'trunk' needs to be included in the spanning-tree portfast command, otherwise its not a trunk port by definition. Graphic shows the port is carrying multiple VLANs to an end client, hence 'trunk' is required.
"spanning-tree portfast trunk"is a hidden Cisco command. Because they dont want you to use it. This question is stupid
Sw1(config-if)#spanning-tree portfas ?
disable Disable portfast for this interface
edge Enable portfast edge on the interface
network Enable portfast network on the interface
Sw1(config-if)#spanning-tree portfast trunk
%Warning: portfast should only be enabled on ports connected to a single
host. Connecting hubs, concentrators, switches, bridges, etc... to this
interface when portfast is enabled, can cause temporary bridging loops.
Use with CAUTION
Sw1(config-if)#spanning-tree portfast?
portfast
Access port (could have used spanning-tree link-type point-to-point, but it was not needed thanks to the duplex link to the server):
sw1#sh span int g0/1
Vlan Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
VLAN0001 Desg FWD 4 128.2 P2p Edge
sw1#
sw1#sh run
****
interface GigabitEthernet0/1
switchport mode access
switchport nonegotiate
negotiation auto
spanning-tree portfast edge
You can get P2p Edge displayed under "show spanning-tree interface ..." in many ways, but only a trunk port is going to show more than one vlan. Thus, we need to use " spanning-tree portfast edge trunk" or " spanning-tree portfast trunk" depending on the IOS version.
I labbed it up in CML to confirm the result.
Provided answer is correct, however the command should include edge if it's required to have the exact same output like this:
spanning-tree portfast edge trunk on the interface
Is a trunk port because Multiple VLANs are in the same port and are edge type that means that the "spanning-tree portfast trunk" command has been issued. without the trunk option porfast command does not work on trunk ports
From ENCORE book, STP Portfast section: Portfast can be enabled on trunk links with the command spanning-tree portfast trunk. However, this command should be used only with ports that are connecting to a single host (such as a server with only one NIC that is running a hypervisor with VMs on different VLANs). Running this command on interfaces
connected to other switches, bridges, and so on can result in a bridging loop.
I abslotly agree with you, it has the same output in the question with addition to a warning msg.
but cisco mentioned this in the OCG, and they want to confuse us with this, although both A and C are aplicable and have the same output, but most ppl chose to go with A.
Well They are two reasons for a port will state in DESG role:
1. When is a root bridge for a VLAN, the ports for this specific VLAN will be DESG ports.
2. After SPT calc the port result in DESG.
Now, the output shows a specific port that has many VLANs, in this way is a trunk port but at the same time have "p2p EDGE" under column Type.
So, the correct answer is "A", for sure.
Answer is A. This is a valid switch IF config:
sw2(config-if)#spanning-tree portfast trunk
%Warning: portfast should only be enabled on ports connected to a single
host. Connecting hubs, concentrators, switches, bridges, etc... to this
interface when portfast is enabled, can cause temporary bridging loops.
Use with CAUTION
sw2(config-if)#
Now look at output based on my config:
sw2#sh spanning-tree int G0/1
Vlan Role Sts Cost Prio.Nbr Type
---------------- ---- --- --------- -------- --------------------------------
VLAN0001 Altn FWD 4 128.25 P2p
VLAN0010 Altn LRN 4 128.25 P2p
VLAN0020 Altn LRN 4 128.25 P2p
VLAN0030 Altn LSN 4 128.25 P2p
VLAN0040 Altn LSN 4 128.25 P2p
sw2#
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