Blade ICE BLADEOS BMD00178 - Manual (Page 28)

BLADEOS 6.3 Application Guide
28 BMD00178, April 2010
Interoperability with Older Hubs
The command-line interface might display link up and link down messages continuously for an
external port that is connected to certain older hub models configured for 100 Mbps half-duplex.
The display might show link up erroneously. This behavior has been observed when connecting the
GbESM with the following devices:
NETGEAR FE104 100 hub
SBS 1000Base-T NIC
3Com Linkbuilder FMS100 Hub 3C250 TX/I
3Com SuperStack II 100TX 3C250C-TX-24/12
Nortel Baystack 204 Hub
If the GbESM is connected to an Alteon Application Switch which requires a link speed of 100
Mbps half-duplex, then enable auto negotiation on the GbESM port with port speed=any,
mode=any, fctl=both, and auto=on.
Link Aggregation Control Protocol
If a static trunk on a GbESM is connected to another GbESM with LACP configured (but no active
LACP trunk), the
/info/l2/trunk command might erroneously report the static trunk as
forwarding.
Since LACP trunks use LACPDU packet to maintain trunking with the partner, there is a possibility
for those packets to be dropped from an extremely busy trunk. If this happens, some links in the
LACP trunk might be removed, then aggregated back to the trunk if an LACPDU is received. To
avoid this unstable LACP trunk link, you can add more links to the trunk to increase the bandwidth,
or use regular static trunk if there are no more links available.
Linking at 10/100Mb
When the link speed for an external connection is forced (i.e. no Auto-Negotiation) to 100 Mbps
and then changed to 10 Mbps, if the external device is changed first, the external device may
erroneously report the link as DOWN even after the GbESM is changed to 10 Mbps.
Solution: At the external device, disconnect and reconnect the cable.