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Anycast RP - Cisco
そっか、デフォルトで最大のIPアドレスを利用されるから、AnycastRP用のLoopbackインタフェースが選択されないようにIGP/EGPでのrouter-idは手動設定するべきなのね
Configuration example to migrate Spanning Tree from PVST+ to MST - Cisco
Spanning Tree Protocol Problems and Related Design Considerations - Cisco
BPDUの最大HOP数は覚えてなかった
Troubleshooting STP on Catalyst Switches Running Cisco IOS System Software - Cisco
Spanning-Tree Protocol Enhancements using Loop Guard and BPDU Skew Detection Features - Cisco

  • Loop guard must be enabled on the non-designated ports (more precisely, on root and alternate ports) for all possible combinations of active topologies.
  • The root guard cannot be enabled on the same port as the loop guard.
  • Loop guard cannot be enabled for ports on which portfast is enabled.

Spanning Tree PortFast BPDU Guard Enhancement - Cisco

When STP BPDU guard disables the port, the port remains in the disabled state unless the port is enabled manually. You can configure a port to reenable itself automatically from the errdisable state. Issue these commands, which set the errdisable-timeout interval and enable the timeout feature
Note: The default timeout interval is 300 seconds and, by default, the timeout feature is disabled.

Understanding and Tuning Spanning Tree Protocol Timers - Cisco

diameter of the STP domain (dia)—This value is the maximum number of bridges between any two points of attachment of end stations. The IEEE recommendation is to consider a maximum diameter of seven bridges for the default STP timers.

max age, forward delayがその他のパラメータによって決まってたとは知らんかった

max age
= End-to-end_BPDU_propa_delay + Message_age_overestimate
= 14 + 6

2 x forward delay
= end-to-end_BPDU_propagation_delay + Message_age_overestimate +
Maximum_frame_lifetime + Maximum_transmission_halt_delay
= 14 + 6 + 7.5 + 1 = 28.5 ）

These calculations leave you with these two final formulas (if you round the 0.5 value):

max_age = (4 x hello) + (2 x dia) – 2
forward_delay = *1 / 2

hello, diaによってmax_age, forward_delayの導出ができるので、helloをいじればその他のタイマーも変わるけど

A decrease of the hello time to 1 sec is the easiest and surest way to decrease the STP parameters. However, remember that if you drop the hello time from 2 sec to 1 sec, you double the number of BPDUs that are sent/received by each bridge.

each BPDU includes the hello, forward delay, and max age STP timers. An IEEE bridge is not concerned about the local configuration of the timers value. The IEEE bridge considers the value of the timers in the BPDU that the bridge receives. Effectively, only a timer that is configured on the root bridge of the STP is important.

タイマーの定義はrootのものが使われるので

you must at least configure any timer changes on the root bridge and on the backup root bridge.

Understanding EtherChannel Inconsistency Detection - Cisco
EtherChannelの対向がチャネル解除されてる状態か…

*1:4 x hello) + (3 x dia