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Functional Descriptions

VMDS-10488 VSC7511 Datasheet Revision 4.2

113

The frame’s VID is used as an address for lookup in the VLAN table and the returned VLAN information

is processed as follows:

•

All ports that are not members of the VLAN are removed from DEST, except if the (DMAC, VID)

match in the MAC table has VLAN_IGNORE set, or if there is no match in the MAC table and

AGENCTRL.FLOOD_IGNORE_VLAN is set.

Note These two exceptions are skipped if AGENCTRL.IGNORE_DMAC_FLAGS is set.

•

If the VLAN_PRIV_VLAN flag in the VLAN table is set, the VLAN is private, and isolated and

community ports must be treated differently. An isolated port is identified as an ingress port for which

PPORT is cleared in the ISOLATED_PORTS register. An community port is identified as an ingress

port for which PPORT is cleared in the COMMUNITY_PORTS register. For frames received on an

isolated port, all isolated and community ports are removed from the forwarding decision. For frames

received on a community port, all isolated ports are removed from the forwarding decision.

•

If VLAN ingress filtering is enabled, it is checked whether PPORT is member of the VLAN

(VLAN_PORT_MASK). If this is not the case, DEST is cleared.

VLAN ingress filtering is enabled per port in the VLANMASK register or per VLAN in the

VLAN_SRC_CHK flag in the VLAN table. If either is set, VLAN ingress filtering is performed.

Next, it is checked whether the ingress port is enabled to forward frames to other front ports and the

source mask (PGID[80+PPORT]) is processed as follows:

•

If PORT_CFG.RECV_ENA for PPORT is 0, DEST is cleared.

•

Any ports, which are cleared in PGID[80+PPORT], are removed from DEST.

Finally, SMAC learning is disabled by setting the LRN_DIS flag when either of the following two

conditions is fulfilled as follows:

•

VLAN_LEARN_DISABLED is set in the VLAN table for the VLAN.

•

A frame is subject to VLAN ingress filtering (frame dropped due to PPORT not being member of

VLAN), and ADVLEARN.VLAN_CHK is set.

3.9.3.3

Aggregation

During the aggregation step, link aggregation is handled. The following table lists the registers

associated with aggregation.

The aggregation step ensures that when a frame is destined for an aggregation group, it is forwarded to

exactly one of the group’s member ports.

For non-aggregated ports, there is a one-to-one correspondence between logical port (LPORT) and

physical port (PPORT). The aggregation step does not change the forwarding decision.

For aggregated ports, all physical ports in the aggregation group map to the same logical port, and the

entry in the destination mask table for the logical port includes all physical ports, which are members of

ISOLATED_PORTS

Private VLAN mask. Isolated ports are cleared in this

mask.

None

COMMUNITY_PORTS

Private VLAN mask. Community ports are cleared in this

mask.

None

ADVLEARN.VLAN_CHK If set and VLAN ingress filtering clears DEST, then SMAC

learning is disabled.

None

Table 87 •

Analyzer Aggregation Registers

Description

Replication

PGID[79:64]

Aggregation mask table.

Table 86 •

VLAN Analysis Registers (continued)

Description

Replication

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