RSTP VS RPVST+

[notaciscoguy]

so I am trying to wrap my head around the finer points of spanning tree. I understand that PVST is the cisco-proprietary method of implementing 802.1d on multiple vlans and by extension RPVST is the cisco proprietary method of implenting 802.1w on multiple vlans. my question(even though I know it would be poor practice), is whether there is a way to implement plain old RSTP on a switch with all ports thrown on a single vlan or if cisco switches just automatically implement RPVST? 

the reason is I often see spanning tree questions ask for the proper commands to implement RSTP but then answers all tell you to type the commands to implement RPVST instead. 

[Moses Fernandes]

Hello,

This is the default settings on cisco 2900 Switch.

VLAN0001
  Spanning tree enabled protocol rstp
  Root ID    Priority    32769

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

32769 = 32768+1 (1=Vlan ID)

By Default all the ports are in the same Vlan. (Vlan 1)

If you find a post helpful, Don't forget to mark it as helpful !!

Regards,

Moses.

[notaciscoguy]

so by default the switch will not change to RPVST+ unless you configure a second VLAN? 

[Moses Fernandes]

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@notaciscoguy wrote:

so by default the switch will not change to RPVST+ unless you configure a second VLAN? 

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Not sure why a cisco switch will change the spanning tree mode which is not compatible (with non cisco switches). After all 802.1'w' and 'd' RSTP and STP are industry standard.

Is RPVST+ a industry standard?

A question I'll ask myself is..

In an all cisco switching environment where we've implemented RPVST+ and everything is working fine....

1. What happens when we bring in a non cisco switch that doesn’t support RPVST+

2. What happens to the loop prevention mechanism then?

3. Why keep a setting as default that doesn't work in all situations?

4. (bonus) Cisco recommends to disable Vlan 1.. Why doesn’t Cisco disable Vlan 1 by default.

The more we question to more we learn.

(To answer your question :- The next vlan you create will also be RSTP)

If you find a post helpful, Don't forget to mark it as helpful !!

Regards,
Moses.

[Joseph W. Doherty]

Hmm, perhaps the closest you might come to once instance of RSTP would be to use MSTP and place all VLANs in one instance.