09-18-2017 04:06 PM - edited 03-08-2019 12:04 PM
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.
09-19-2017 04:30 AM
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.
09-19-2017 07:51 AM
so by default the switch will not change to RPVST+ unless you configure a second VLAN?
09-20-2017 06:58 AM
@notaciscoguy wrote:so by default the switch will not change to RPVST+ unless you configure a second VLAN?
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.
09-19-2017 08:08 AM
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