IBM 9077 manual ATM OC-12c Backbone One Port

grf16:/root brstat
Bridge Group bg1
Spanning Tree:	Enabled
Designated Root:	32768 00:c0:80:84:8c:eb
Bridge ID:	32768 00:c0:80:96:38:68
Root Port: ga0180, Root Path Cost: 10
Topology Change Detected: No
Root Max Age: 20, Hello Time:		2, Forward Delay: 15
Bridge Max Age: 20, Hello Time:		2, Forward Delay: 15, Hold Time: 1
		Path	Desig Desig	Desig
Interface Port ID Con State		Cost	Cost Bridge	Port

--------- ------- --- ---------- ----- ----- ----------------------- -------

ga010	128 1	No Disabled	10
*ga0180	128 2	Yes Forwarding 10		0	32768 00:c0:80:84:8c:eb 128 2
Dump snapshot finished at Mon Jun			15 20:01:51 1998

When port 0 is plugged in again, it resumes and takes over port 1, which in turn falls back to the blocked state, as the following screen shot proves:

grf16:/root brstat
Bridge Group bg1
Spanning Tree:	Enabled
Designated Root:	32768 00:c0:80:84:8c:eb
Bridge ID:	32768 00:c0:80:96:38:68
Root Port: ga010, Root Path Cost: 10
Topology Change Detected: No
Root Max Age: 20, Hello Time:		2, Forward Delay: 15
Bridge Max Age: 20, Hello Time:		2, Forward Delay: 15, Hold Time: 1
		Path	Desig Desig	Desig
Interface Port ID Con State		Cost	Cost Bridge	Port

--------- ------- --- ---------- ----- ----- -----------------------							-------
*ga010	128 1	Yes Forwarding 10		0	32768	00:c0:80:84:8c:eb	128 1
ga0180	128 2	Yes Blocking	10	0	32768	00:c0:80:84:8c:eb	128 2
Dump snapshot finished at Mon Jun			15 20:02:03 1998

We expect this to happen also with the one-ported ATM OC-12c 622Mbit media card, so if two of them are put into a bridging group, this could be a fault tolerant scenario.

7.2 ATM OC-12c Backbone - One Port

This setup is basically the same as using just one port of an ATM OC-3c card, as described in Section 7.1.1, “ATM OC-3c Backbone - Using One Port” on page 210.

222IBM 9077 SP Switch Router: Get Connected to the SP Switch