VSC7440 datasheet(287/444 Pages) MICROSEMI

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Functional Descriptions

VMDS-10492 VSC7440 Datasheet Revision 4.2

270

The device supports mirroring frames from either Rx ports (ingress mirror) or Tx ports (egress mirror).

Frames either received on a port (Rx mirror) or frames sent to a port (Tx mirror) are copied to a mirror

destination port.

For Tx mirroring, the rewriter rewrites the frame sent to the mirror destination port, exactly as the original

frame copy is rewritten when forwarded to the mirror probe port. The mirror probe port number must be

configured in the rewriter using register MIRROR_TX_PORT.

For Rx mirroring, the rewriter makes no modifications to the frame, so an exact copy of the original frame

as received on the mirror probe port (ingress port) is sent out on the mirror destination port.

The analyzer controls both Rx and Tx mirroring. For more information, see Mirroring, page 206. The

rewriter obtains mirror information for the frame from the internal frame header.

IFH.FWD.MIRROR_PROBE indicates if the frame is a mirror copy and if so, to which of three mirror

probes the frame belongs. Encoding is as follows.

•

MIRROR_PROBE = 0: Frame is not a mirror copy

•

MIRROR_PROBE = 1: Frame is mirrored using mirror probe set 1

•

MIRROR_PROBE = 2: Frame is mirrored using mirror probe set 2

•

MIRROR_PROBE = 3: Frame is mirrored using mirror probe set 3

In addition, the IFH.FWD.RX_MIRROR bit indicates if the frame is Rx mirrored (1) or Tx mirrored (0).

When mirroring traffic to a device that is not directly attached to the VSC7440 device, it may be required

to push one or two VLAN tags to mirrored frame copies as to not violate general VLAN membership for

the mirror destination port. These VLAN tags are called “remote mirror VLAN tags” and can be

configured individually for each mirror probe. When enabled, the remote mirror VLAN tags are pushed

onto all mirrored traffic by the rewriter whether it is an Rx mirrored frame or a Tx mirrored frame. For

remote mirroring it is also possible to add MPLS capsulation using the encapsulation table if this is

required for forwarding the frame.

The REMOTE_MIRROR_ENA register configures whether to add one or two remote mirror VLAN tags or

MPLS encapsulation. The REMOTE_ENCAP_ID bit selects the MPLS encapsulation to be used.

For Tx mirroring, care must be taken if maximum frame expansion is already required by the rewriter for

the TX mirror probe port. In this case enabling remote mirror VLAN tags or encapsulation would add an

extra frame expansion, which can cause frame disruption on the mirror destination port. It is not possible

to add remote mirror encapsulation to a frame that already has encapsulation added by ES0. In this case

the remote mirror encapsulation ID will replace the ID selected by the ES0.ENCAP_ID action.

3.26.13 Internal Frame Header Insertion

The rewriter can be configured to insert the internal frame header (IFH) into the frame upon transmission.

For more information about the IFH, Frame Headers, page 13.

MIRROR_TAG_x_CFG:

TAG_x_PCP_VAL

Mirror Q-tag PCP value.

2× mirror

probes

MIRROR_TAG_x_CFG:

TAG_x_PCP_SEL

Selection of mirror Q-tag PCP values.

2× mirror

probes

MIRROR_TAG_x_CFG:

TAG_x_DEI_VAL

Mirror Q-tag DEI values.

2× mirror

probes

MIRROR_TAG_x_CFG:

TAG_x_VID_VAL

Mirror Q-tag VID values.

2× mirror

probes

MIRROR_TAG_x_CFG:

TAG_x_TPID_SEL

The tag protocol identifier (TPID) for the remote mirror VLAN tag.

2× mirror

probes

Table 190 •

Mirror Probe Configuration Registers (continued)

Description

Replication

VSC7440 Datasheet(PDF) 287 Page - Microsemi Corporation

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