Mellanox MLNX-OS® User Manualfor SX1018HP Ethernet Managed Blade Switch

Rev 1.6.9
Mellanox Technologies
83
Mellanox Technologies Confidential
The system on the receiving end of the analyzer port must be set to handle the egress traffic. If it
is not, it might discard it and indicate this in its statistics (packet too long).
5.10.1.3 Header Format
Ingress traffic from the source interface can be man
ipulated in several ways depending on the
network layout using the command
header-format .
If the analyzer system is directly connect
ed to the destination interface, then the only parameters
that can be configured on the port are the MTU, speed and port based flow control. Priority flow
control is not supported is this case. However, if the analyzer system is indirectly connected to
the destination interface, there are two options for switching the mirrored data to the analyzer
system:
• A VLAN tag may be added to the Ethernet header of the mirrored traffic
• An Ethernet header can be added with include
a new destination address and VLAN tag
Figure 12: Header Format Options
SourceFrame MirrorFrame
SourceFrame MirrorFrame
SourceFrame MirrorFrame
SourceFrame MirrorFrame
Data
Type/
Len
SADA
Data
Type/
Len
SADA
Data
Type/
Len
SADA
Data
Type/
Len
SADA Data
Type/
Len
SADA
Data
Type/
Len
SADADA SA
0x8949
Data
Type/
Len
SADADA SA
0x89490x8100
VLAN
Data
Type/
Len
0x8100
DA VLANSA
local
add‐vlan
add‐ethernet‐header
add‐ethernet‐header
(+vlan)
5.10.1.4 Congestion Control
The destination ports might receive pause frames that
lead to congestion in the switch port. In
addition, too much traffic directed to the analyzer port (for example 40GbE mirror port is
directed into 10G analyzer port) might also lead to congestion.
In case of congestion:
• When best effort mode is enable
d on the analyzer port, SwitchX drops excessive traffic
headed to the analyzer port using tail drop mechanism, however, the regular data (mir-
rored data heading to its original port) does not s
uffer from a delay or drops due to the
analyzer port congestion.
• When the best effort mode on the analyzer po
rt is disabled, the SwitchX does not drop
the excessive traffic. This might lead to buffer exhaustion and data path packet loss.
It must be taken into account that adding headers increases packet size.