default stp port cost value on hp2530

[tomoyuki]

Hi 

I  would like to confirm about default stp port cost value of hp2530.

My understanding...

In only Gigabit link, default stp port cost value is 4.

In 2 Gigabit Bagg (LACP) link , default stp port cost is 4 . (same of other link speed value.) , and Cisco  etherchannel is 3.

But,  following environment, In hp2530 Giga link's stp port cost is 5.

Is this correct ??

[edge sw]                      [access sw#1]        [core sw#1]

hp2530-24 port 23 ------ hp5500-24 ------- hp5500-24
                  port24                  || bagg               || bagg
                    |------------- hp5500-24 ------- hp5500-24

                                      [access sw#2]      [ core sw#2]

bagg ... configured 2 giga-link ports

STP mode …RSTP

bridge priority … core sw#1 =0 (route bridge)
core sw#2 =4096
access sw#1 =8192
access sw#1 =16384
edge sw =20480

port cost value …  default

block port … access sw#2 bagg1 , edge sw port24

Each links are negotiated in gigabit link