Single Forwarding Database Operation - HP 3500 Series Advanced Traffic Management Manual

Static Virtual LANs (VLANs)
Multiple VLAN Considerations
1-18
Table 1-6. Forwarding Database Structure for Managed HP Switches
Multiple Forwarding Databases* Single Forwarding Database*
Series E8200zl switches
Switch E6600
Series E6400cl switches
Switch E6200yl
Switch E6108
Series E5400zl switches
Series E5300xl switches
Series E4200vl switches
Series E4100gl switches
Series E3500 switches
Series E3500yl switches
Series E3400cl switches
Switch E2810
Series E2800 switches
Series E2600/2600-PWR switches
Series E2510 switches
*To determine whether other vendors' devices use single-
forwarding or multiple-forwarding database architectures, refer to
the documentation provided for those devices.

Single Forwarding Database Operation

When a packet arrives with a destination MAC address that matches a MAC
address in the switch's forwarding table, the switch tries to send the packet
to the port listed for that MAC address. But, if the destination port is in a
different VLAN than the VLAN on which the packet was received, the switch
drops the packet. This is not a problem for a switch with a multiple forwarding
database (refer to table 1-6, above) because the switch allows multiple
instances of a given MAC address; one for each valid destination. However, a
switch with a single forwarding database allows only one instance of a given
MAC address. If (1) you connect the two types of switches through multiple
ports or trunks belonging to different VLANs, and (2) enable routing on the
switch having the multiple forwarding database; then, on the switch having
the single forwarding database, the port and VLAN record it maintains for the
Switch E1600M/E2400M/
E2424M
Switch E4000M/E8000M
Series E2500 switches
Switch E2000
Switch E800T