Technical data

Page 19
• On both ISL and Edge ports, sFlow sampling is supported only in the inbound direction.
• The DNS configuration is primarily used for LDAP. It should be noted that DNS look-up will not be
used by PING, Traceroute, or any other services. These services will still require specifying the
actual IP address.
• VM-Aware Network Automation will work only with VMware vSphere version 4.0, 4.1 and 5.0.
• Enabling VM-Aware Network Automation will cause the Brocade VDX switch to drop CDP packets.
• Any local loop, even within a single fabric, can cause broadcast storms and potentially impact the
entire network. A local loop in one fabric may impact another fabric in the case of VCS-to-VCS
fabric connectivity. Using ELD to prevent loops is highly recommended.
• When ELD is enabled, toggling global or interface-level native VLAN tag mode can cause ELD not
to function as expected on that VLAN. It is not recommended to make such changes after ELD is
enabled; however, in the event that this occurs, disable and then enable ELD to resume proper
functionality.
• If multiple VLANs are configured on a switch, in order to enable certain features such as IGMP or
PVST, it is recommended that specific features be enabled on a per-VLAN basis instead of
enabling them globally.
• When a new switch is added to an existing VCS fabric and if the new switch takes the role of
principal node, the other switches in the fabric will receive the configuration of the distributed
features such as Virtual IP and VM-Aware Network Automation from the newly added switch. This
will cause the existing distributed configuration to be overwritten by the newly added switch in the
principal role.
• When interoperating with a Brocade 8000, it is recommended to set the mac-aging time to 0 on
the VDX switch to prevent any adverse impact caused by certain errors generated by the
Brocade 8000.
• When configuring LACP LAG between a Brocade VDX switch and non-Brocade switches, it is highly
recommended that you enable the VLAG ignore-split on the Brocade VDX switch. The ignore-split
option is enabled by default in NOS v2.1.
• When a MAC ACL with several clauses is applied to a port channel that is a member of 750 or
more VLANS, the MAC ACL counters may take several minutes to be enabled due to the
processing load associated with such configurations.
• It is recommended that you use the same CoS Tail Drop Threshold on all members of a port
channel to avoid unpredictable behavior.
• Under certain stress conditions, the copy support command may time out for some modules. In
such cases, it is recommended that you retry copy support with a higher timeout multiplier value.
• It is highly recommended that you copy the configuration file to running-config and then save the
running-config to startup-config, instead of directly copying the external configuration file to
startup-config, especially when using fabric-distributed features such as zoning, VM-Aware
Network Automation, and Virtual IP.
• It is not recommend to have FCoE ports and Long Distance ISL ports in the same port groups. This
configuration will NOT be prevented by the CLI; however it can result in unpredictable behavior for
FCoE traffic.
• Brocade VDX switches do not support tunneling non-standard BPDUs and thus IEEE BPDUs
(0180:C200:0000) generated as tagged packets in STP/RSTP/MSTP modes may not be tunneled
successfully across a VCS fabric. However, Brocade VDX switches support tunneling standards-
based BPDUs such as untagged IEEE BPDUs, and tagged or untagged PVST BPDUs
(0100:0CCC:CCCD).
•
When configuring a large ACL and VLAN configuration on a single physical interface or port
channel, it may take up to 20 minutes for the ACL statistics counter to start counting packets.