RSTP parameters in Cisco Packet Tracer

[ToyzMachine]

Hey guys!

Trying to build a RSTP network simulation with Packet Tracer 8.1 but have some doubts.

Why is the max age still shows 20s instead of 6s after the switch has been configured to run RSTP?

The switch model deployed is 2960.

Thanks.

Alex

[Jon Marshall]

It shows that because it is the default ie. from a production 2960 switch - 

VLAN0024
Spanning tree enabled protocol rstp
Root ID Priority 24
Address 0016.46fd.1500
Cost 23
Port 24 (GigabitEthernet0/24)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 12312 (priority 12288 sys-id-ext 24)
Address 001d.460a.f100
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300 sec

Jon

[Flavio Miranda]

20 seconds is the default value . You can tunne it from 6 up to 40. But, PacketTracer does not allow it. 

The option we have is priority and root config:

Switch(config)#spanning-tree vlan 20 ?
priority Set the bridge priority for the spanning tree
root Configure switch as root
<cr>

[Martin L]

I think STP values stay the same even if u switch to RSTP: Hence, that's why u see MAx age, Forward Delay , hellos are default STP timers values.  By default switch runs and shows STP values.

RSTP is backwards compatibility with STP.  This means RSTP switch listens, accepts and understands regular legacy STP.  you could have 1 port in  STP while all others are RSTP.

Regards, ML
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