STP Neighbour Type

Answered Question
Jan 14th, 2008

Hi all,

I would like to get a concrete answer for the following Neighbor Type when I issue a show span command.

P2p Peer(STP)

David Hucaby book says that it means that the neighbor is running traditional SPT (i.e. 802.1d) while on a Cisco site at http://www.cisco.com/en/US/products/hw/switches/ps708/products_configuration_example09186a00807b0670.shtml it suggests that the neighbor is running PVST.

Which one is correct? If my switch is running PVST and I see P2p Peer(STP) does it mean traditional is running on the neighbor, and if I look on the normal STP switch, will the PVST neighbor appear as P2p Peer(STP)?

Thanks in advance,

Chris

I have this problem too.
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Correct Answer by Jon Marshall about 8 years 10 months ago

Chris

PVST+ still runs 802.1d spanning-tree, it's just that it runs an 802.1d instance per vlan. So the book and the document do not contradict each other.

The P2p Peer(STP) will appear when the switch is running Rapid PVST+ and the device at the other end of the link is not running Rapid PVST+.

From the doc you highlighted

=============================================

VLAN0010

Spanning tree enabled protocol --> rstp <-- the switch is running rapid PVST+

Root ID Priority 24586

Address 0015.63f6.b700

Cost 19

Port 107 (FastEthernet3/0/1)

Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 32778 (priority 32768 sys-id-ext 10)

Address 000f.f794.3d00

Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Aging Time 300

Interface Role Sts Cost Prio.Nbr Type

---------------- ---- --- --------- -------- --------------------------------

Fa3/0/1 Root FWD 19 128.107 P2p Peer(STP)

Fa3/0/2 Altn BLK 19 128.108 P2p Peer(STP)

!--- Type P2p Peer(STP) represents that the neighbor switch runs PVST.

=============================================

HTH

Jon

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Correct Answer
Jon Marshall Mon, 01/14/2008 - 11:03

Chris

PVST+ still runs 802.1d spanning-tree, it's just that it runs an 802.1d instance per vlan. So the book and the document do not contradict each other.

The P2p Peer(STP) will appear when the switch is running Rapid PVST+ and the device at the other end of the link is not running Rapid PVST+.

From the doc you highlighted

=============================================

VLAN0010

Spanning tree enabled protocol --> rstp <-- the switch is running rapid PVST+

Root ID Priority 24586

Address 0015.63f6.b700

Cost 19

Port 107 (FastEthernet3/0/1)

Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 32778 (priority 32768 sys-id-ext 10)

Address 000f.f794.3d00

Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Aging Time 300

Interface Role Sts Cost Prio.Nbr Type

---------------- ---- --- --------- -------- --------------------------------

Fa3/0/1 Root FWD 19 128.107 P2p Peer(STP)

Fa3/0/2 Altn BLK 19 128.108 P2p Peer(STP)

!--- Type P2p Peer(STP) represents that the neighbor switch runs PVST.

=============================================

HTH

Jon

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