Brocade FastIron Ethernet Switch Platform and Layer 2 Switching Configuration Guide - Manual (Page 127)

This command clears the Packets sent, Packets received, and Transitions counters in the show link
keepalive ethernet [slotnum /]portnum display.
Protected link groups
A protected link group minimizes disruption to the network by protecting critical links from loss of data
and power. In a protected link group, one port in the group acts as the primary or active link, and the
other ports act as secondary or standby links. The active link carries the traffic. If the active link goes
down, one of the standby links takes over.
During normal operation, the active port in a protected link group is enabled and the standby ports are
logically disabled. If the active port fails, the Brocade device immediately enables one of the standby
ports, and switches traffic to the standby port. The standby port becomes the new, active port.
About active ports
When you create a protected link group, you can optionally specify which port in the protected link
group is the active port. If you do not explicitly configure an active port, the Brocade device dynamically
assigns one. A dynamic active port is the first port in the protected link group that comes up (usually the
lowest numbered port in the group).
Static and dynamic active ports operate as follows:
• A static active port (an active port that you explicitly configured) pre-empts other ports in the
protected link group. So, if a static active link comes back up after a failure, the Brocade device will
revert to this link as the active link.
• A dynamic active port (an active port assigned by the software) is non-pre-emptive. Therefore, if a
dynamic active link comes back up after a failure, the Brocade device does not revert to this link, but
continues carrying traffic on the current active link.
Using UDLD with protected link groups
You can use UDLD with protected link groups to detect uni-directional link failures and to improve the
speed at which the device detects a failure in the link. Use UDLD and protected link groups
simultaneously when the FastIron X Series device is connected to a device with slower link detection
times.
NOTE
When UDLD and protected links are configured on a port and the link goes down, protected links will
not come up after UDLD becomes "healthy" again without first physically disabling then re-enabling the
link.
UDLD with protected link groups configuration notes
• You can configure a maximum of 32 protected link groups.
• There is no restriction on the number of ports in a protected link group.
• Each port can belong to one protected link group at a time.
• On FastIron X Series devices, there is no restriction on the type of ports in a protected link group.
FastIron X Series devices support protected link groups consisting of 10-GbE ports, Gbps fiber ports,
10/100/1000 copper ports, and 10/100 ports, or any combination thereof.
Protected link groups
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