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Specifying max-age and forward-time
Hello,
I'm wondering when, if ever, we should specify the max-age and forward-time values when using RSTP on an N2000 and/or S4048 switch?
Regards.
Unsolved
This post is more than 5 years old
15 Posts
0
1336
Hello,
I'm wondering when, if ever, we should specify the max-age and forward-time values when using RSTP on an N2000 and/or S4048 switch?
Regards.
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Anonymous
274.2K Posts
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August 22nd, 2016 07:00
Those timers are used with STP, but not with RSTP. The N4000 should default to RSTP, while the S4048 would need to be configured for RSTP. Page 830: http://dell.to/2bpMvqP
Cisco has some good reading material on fine tuning timers when using STP.
http://bit.ly/2bIChzL
Hope this info helps.
hammertime1983
15 Posts
0
August 24th, 2016 06:00
Thanks for the reply.
it looks like on the CLI reference guide for S4048 p835 http://dell.to/2bpMvqP looks like you can edit those parameters for RSTP?
Also, I ran the following on an N2048P and the hello-time appears to change:
console(config)#show spanning-tree
Spanning Tree: Enabled - BPDU Flooding: Disabled - Portfast BPDU Filtering: Disabled
Mode: rstp
CST Regional Root: 80:00:F4:8E:38:02:9B:2B
Regional Root Path Cost: 0
ROOT ID
Priority 32768
Address F48E.3802.9B2B
This Switch is the Root.
Hello Time: 2s Max Age: 20s Forward Delay: 15s Transmit Hold Count: 6s
Bridge Max Hops: 20
Interfaces
console(config)#spanning-tree max-age 6
console(config)#show spanning-tree
Spanning Tree: Enabled - BPDU Flooding: Disabled - Portfast BPDU Filtering: Disabled
Mode: rstp
CST Regional Root: 80:00:F4:8E:38:02:9B:2B
Regional Root Path Cost: 0
ROOT ID
Priority 32768
Address F48E.3802.9B2B
This Switch is the Root.
Hello Time: 2s Max Age: 6s Forward Delay: 15s Transmit Hold Count: 6s
Bridge Max Hops: 20
Interfaces
Anonymous
274.2K Posts
0
August 24th, 2016 07:00
RSTP is backwards compatible with STP, so these values are mostly used when this switch connects to a device that is configured for STP. When the network is running RSTP if hellos are not received 3 consecutive times, or if the max age time is reached, then information is aged out. In an RSTP environment, the 3 lost hellos are going to occur before the max age time is reached.
Have you done any testing on what the current reconvergence time is? Are there devices on the network running STP and not RSTP? I suggest only making changes to these settings if you have identified a specific need to make changes.