Hitachi GR2000 Series, Installation Manual

Page: 282 / 410

When bridge is defined on an interface where multiple VCs are grouped, BPDUs or
relay frames not learned are broadcast to all the VCs in the group. Consequently, it is
cautioned that an inadvertent addition of bridge definition to an existing grouped
interface may cause unnecessary traffic to flow through the interface if the group
includes a VC not using protocols other than IP. To avoid such occurrence of
unnecessary traffic, it is advised to separate the group into two—one comprising VCs
to use the bridge function, and the other not using protocols other than IP—and
define these groups to respective interfaces. The same is advised when you further
add IPX definition to the existing interface.
4.11.6 Bridge Definition on ISDN Interface
Bridge definition on an ISDN interface is available only on such interface where IP
interface is defined to a single ISDN peer. The IP interface should be point-to-point
type. Bridge definition on an ISDN interface with ISDN peer group is not available.
Since the spanning-tree protocol is not available on an ISDN interface, each bridge
interface can be defined “yes” or “no.” In addition, when you plan a new ISDN
network where the bridge interface definition is anticipated, it is advised that you
explicitly avoid a loop configuration in the network.