Effect Of Downstream Vlan Tagging On Untagged, Mirrored Traffic - HP ProCurve Management And Configuration Manual

Table B-2. Maximum Frame Sizes for Mirroring
Frame Type
Configuration
Non-Jumbo
(default config.)
1
Jumbo on All VLANs
1
Jumbo On All But
Source VLAN
Non-Jumbo
1
Jumbo on All VLANs
1
Jumbo On All But
Source VLAN
1
Jumbo frames are allowed on ports operating at or above 1 Gbps.
2
For local mirroring, a non-Jumbo configuration on the source VLAN dictates an MTU of 1518
bytes for untagged frames, and an MTU of 1522 for tagged frames, regardless of the Jumbo
configuration on any other VLANs on the switch.
Effect of Downstream VLAN Tagging on
Untagged, Mirrored Traffic
In a remote mirroring application, if mirrored traffic leaves the switch without
802.1Q VLAN tagging, but is forwarded through a downstream device that adds
802.1Q VLAN tags, then the MTU for untagged, mirrored frames leaving the
source switch is reduced below the values shown in table B-2. That is, if the
MTU on the path to the destination is 1522 bytes, then untagged, mirrored
frames leaving the source switch cannot exceed 1518 bytes. If the MTU on the
path to the destination is 9220 bytes, then untagged, mirrored frames leaving
the source switch cannot exceed 9216 bytes.
Monitoring and Analyzing Switch Operation
Maximum VLAN Frame Mirrored
Frame Tag to Local Port
Size
Data
1518 0
9216 0
1518 0
1522 4 1522
9220 4
1522 4
Traffic Mirroring
Frame Mirrored to
Remote Port
Data IPv4 Header
1518 1464
9216 9162
2
n/a 1464
1468
9218 9164
2
n/a 1468
54
54
54
54
54
54
B-69