Figure 13. Stp Bpdu Cost Modification - Olicom CrossFire 8730 Reference Manual

Secondary 1 will become forwarding first, when the primary connection fails. The
Secondary 2 connection is chosen only after the Secondary 1 connection.
Cost modification of BRF to CRF link:
•
For the Secondary 1 connection, a value of 20,000 will be added to the cost of
the internal BRF to CRF link.
•
For the Secondary 2 connection, a value of 40,000 will be added to the cost of
the internal BRF to CRF link
In the picture below, the CrossFire 8730 Switch 2 and Ethernet Switch 2 know that
the root path cost seen from the secondary link is 20,000 bigger, than the root path
cost of the primary link seen by the CrossFire 8730 Switch 1 and Ethernet Switch
1. This means that the secondary link will be blocked on the internal CRF to BRF
link.
If the spanning tree costs are configured manually for backup connection to
Ethernet, each connection attribute should be set to Primary and then spanning tree
costs must be changed on each side of the backup link.
Primary CRF
translational
connection. On
this CRF, the STP cost
stays unmodified.
STACK-LINK
STATUS
FAULT
TX RX ATTACH 21-22
MANAGEMENT PWR DIAG ERR RST
1 2 3 4 5 6 7 8

Figure 13. STP BPDU Cost Modification

CrossFire 8730 Switch Reference Guide, DOC-7047 v. 1.1
Ethernet
Ethernet Switch 1
CrossFire 8730
Fast Ethernet Translation Switch
ACT ACT ACT ACT
100 100 STATUS 100 100
LINK LINK FAULT LINK LINK
21 22 FAST ETHERNET 25-26 25 26
9 10 11 12 13 14 15 16 17 18 19 20
CrossFire Switch 8730 1
Token-Ring
cloud
SR Bridge
Ethernet Switch 2
CrossFire 8730
Fast Ethernet Translation Switch
ACT ACT ACT
STACK-LINK
STATUS STATUS
100 100 100
FAULT LINK LINK FAULT LINK
TX RX ATTACH 21-22 21 22 FAST ETHERNET 25-26 25 26
MANAGEMENT PWR DIAG ERR RST
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
CrossFire 8730 Switch 2
Token-Ring
cloud
Secondary CRF
translational connection.
On this CRF, the STP cost of
the internal BRF to CRF link
is modified.
ACT
100
LINK
20
Switch Overview
31