BigIron RX Series Configuration Guide
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Configuring RSTP parameters
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Fast uplink span
The Fast Port Span feature described in the previous section enhances STP performance for end
stations. The Fast Uplink feature enhances STP performance for wiring closet switches with
redundant uplinks. Using the default value for the standard STP forward delay, convergence
following a transition from an active link to a redundant link can take 30 seconds (15 seconds for
listening and an additional 15 seconds for learning).
You can use the Fast Uplink feature on a Brocade device deployed as a wiring closet switch to
decrease the convergence time for the uplink ports to another device to just four seconds (two
seconds for listening and two seconds for learning). The wiring closet switch must be a Brocade
device but the device at the other end of the link can be a Brocade device or another vendor’s
switch. Configuration of the Fast Uplink Span feature takes place entirely on the Brocade device.
To configure the Fast Uplink Span feature, specify a group of ports that have redundant uplinks on
the wiring closet switch (Brocade device) as members of a Fast Uplink Group. If the active link
becomes unavailable, the Fast Uplink Span feature transitions the forwarding to one of the other
ports in four seconds. You can configure one Fast Uplink Span group on the device. All Fast Uplink
Span ports are members of the same Fast Uplink Span group.
NOTE
To avoid the potential for temporary bridging loops, Brocade recommends that you use the Fast
Uplink feature only for wiring closet switches (switches at the edge of the network cloud). In
addition, enable the feature only on a group of ports intended for redundancy, so that at any given
time only one of the ports is expected to be in the forwarding state.
NOTE
When the BigIron RX first comes up or when STP is first enabled, the uplink ports still must go
through the standard STP state transition without any acceleration. This behavior guards against
temporary routing loops as the switch tries to determine the states for all the ports. Fast Uplink Span
acceleration applies only when a working uplink becomes unavailable.
Fast uplink span rules for trunk groups
If you add a port to a Fast Uplink Span group that is a member of a trunk group, the following rules
apply:
•
If you add the primary port of a trunk group to the Fast Uplink Span group, all other ports in the
trunk group are automatically included in the group. Similarly, if you remove the primary port in
a trunk group from the Fast Uplink Span group, the other ports in the trunk group are
automatically removed from the Fast Uplink Span group.
•
You cannot add a subset of the ports in a trunk group to the Fast Uplink Span group. All ports
in a trunk group have the same Fast Uplink Span property, as they do for other port properties.
•
If the working trunk group is partially down but not completely down, no switch-over to the
backup occurs. This behavior is the same as in the standard STP feature.
•
If the working trunk group is completely down, a backup trunk group can go through an
accelerated transition only if the following are true:
•
The trunk group is included in the fast uplink group.
•
All other ports except those in this trunk group are either disabled or blocked. The
accelerated transition applies to all ports in this trunk group.
Summary of Contents for Brocade DCX
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Page 88: ...16 BigIron RX Series Configuration Guide 53 1001810 01 Searching and filtering output 1 ...
Page 300: ...228 BigIron RX Series Configuration Guide 53 1001810 01 Displaying IP information 7 ...
Page 318: ...246 BigIron RX Series Configuration Guide 53 1001810 01 Deploying a LAG 8 ...
Page 418: ...346 BigIron RX Series Configuration Guide 53 1001810 01 SuperSpan 12 ...
Page 482: ...410 BigIron RX Series Configuration Guide 53 1001810 01 MRP CLI example 14 ...
Page 506: ...434 BigIron RX Series Configuration Guide 53 1001810 01 Displaying VSRP information 15 ...
Page 582: ...510 BigIron RX Series Configuration Guide 53 1001810 01 Viewing Layer 2 ACLs 20 ...
Page 634: ...562 BigIron RX Series Configuration Guide 53 1001810 01 Troubleshooting ACLs 21 ...
Page 642: ...570 BigIron RX Series Configuration Guide 53 1001810 01 Trunk formation 22 ...
Page 746: ...674 BigIron RX Series Configuration Guide 53 1001810 01 Displaying RIP filters 24 ...
Page 808: ...736 BigIron RX Series Configuration Guide 53 1001810 01 Displaying OSPF information 25 ...
Page 938: ...866 BigIron RX Series Configuration Guide 53 1001810 01 Displaying MBGP information 27 ...
Page 950: ...878 BigIron RX Series Configuration Guide 53 1001810 01 Using secure copy 28 ...
Page 988: ...916 BigIron RX Series Configuration Guide 53 1001810 01 Clearing IS IS information 29 ...
Page 1054: ...982 BigIron RX Series Configuration Guide 53 1001810 01 Sample 802 1x configurations 33 ...
Page 1108: ...1036 BigIron RX Series Configuration Guide 53 1001810 01 sFlow 39 ...
Page 1190: ...1118 BigIron RX Series Configuration Guide 53 1001810 01 Displaying RIPng information 44 ...
Page 1270: ...1198 BigIron RX Series Configuration Guide 53 1001810 01 Displaying ACLs 47 ...
Page 1310: ...1238 BigIron RX Series Configuration Guide 53 1001810 01 Displaying OSPFv3 information 48 ...
Page 1382: ...1310 BigIron RX Series Configuration Guide 53 1001810 01 Commands That Require a Reload D ...
Page 1435: ...BigIron RX Series Configuration Guide 1363 53 1001810 01 VSRP E ...
Page 1436: ...1364 BigIron RX Series Configuration Guide 53 1001810 01 VSRP E ...