Brocade FastIron Ethernet Switch Platform and Layer 2 Switching Configuration Guide - Manual (Page 248)

ACL and rate limiting effects TABLE 40
ACL profile Ingress result Egress result
Ingress ACL on port Packets ingress mirrored at expected
(sent) rate Packets egress mirrored at expected
(sent) rate
Egress ACL on port Packets ingress mirrored at expected
(sent) rate Packets egress mirrored at expected
(sent) rate
Ingress rate limiting on port Packets ingress mirrored at expected
(sent) rate
Packets egress mirrored at the limited
rate
Egress rate shaping on port Packets ingress mirrored at expected
(sent) rate
Packets egress mirrored at expected
(sent) rate
Tagged versus untagged ports in VLANs
The following table describes how VLAN-based mirroring coexists with port mirroring, assuming a
VLAN consisting of one ingress and one egress port.
VLAN-based mirroring and port mirroring effects TABLE 41
Packets sent VLAN-based
mirroring direction
Which port in VLAN
is monitored Ingress mirror traffic
count expectation Egress mirror traffic
count expectation
10000 Ingress Ingress ~10000 ~0
10000 Egress Egress ~0 ~20000
10000 Ingress Egress ~10000 ~10000
10000 Egress Ingress ~10000 ~10000
The above table can be summarized into the following two rules, assuming that VLAN-based mirroring
and port mirrroring are operating concurrently.
• If the VLAN is ingress monitored, and ports belonging to the VLAN are also ingress monitored, the
ingress traffic is only mirrored once and there are no duplicated mirrored packets.
• If the VLAN is egress monitored and ports belonging to the VLAN are also egress monitored, the
egress traffic is mirrored for each egress port, as well as the VLAN, resulting in several duplicated
mirrored packets. The count of duplicate packets is computed as (1 + Number of egress mirrored
ports in the VLAN) * Number of egress packets.
In addition to the previously mentioned rules, the behavior of VLAN-based mirroring is affected by the
tag type of the ports belonging to that VLAN, as shown in the following table.
VLAN-based mirroring behavior: Tagged versus untagged ports TABLE 42
Ingress tag type Egress tag type VLAN-based mirroring direction Mirrored traffic tag type
Untagged Untagged Ingress Untagged
Untagged Untagged Egress Tagged
Tagged versus untagged ports in VLANs
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