Product guide

Spanning-Tree Operation
802.1D Spanning-Tree Protocol (STP) on 5300xl, 3400cl and 6400cl Switches
on the other end of the links can be either ProCurve devices or another
vendor’s devices, regardless of whether they support fast uplink. For example:
• STP is running on both switches.
• Port “A” and port “B” are both configured for
fast-uplink STP (Mode = Uplink).
STP Root
Switch
3400cl or
5300xl
Switch
(Wiring
Closet or
Edge
Switch)
LAN
STP Blocking
Port A is the STP root port.
B
Port B provides a backup redundant link.
that becomes the new STP root port
(uplink port) if the link through port A
fails.
C
A
D
E
Figure 6-12. Example of How To Implement Fast-Uplink STP
Terminology
Term Definition
downlink port A switch port that is linked to a port on another switch (or to an end node) that is sequentially
(downstream port)
further away from the STP root device. For example, port “C” in figure 6-12, above, is a
downlink port.
edge switch For the purposes of fast-uplink STP, this is a switch that has no other switches connected to
its downlink ports. An edge switch is sequentially further from the root device than other
switches to which it is connected. Also termed wiring closet switch or leaf switch. For
example, switch “4” in figure 6-13 (page 6-33) is an edge switch.
interior switch In an STP environment, a switch that is sequentially closer to the STP root device than one
or more other switches to which it is connected. For example, switches “1”, “2”, and “3” in
figure 6-13 (page 6-33) are interior switches.
single-instance spanning A single spanning-tree ensuring that there are no logical network loops associated with any
tree of the connections to the switch, regardless of whether there are any VLANs configured on
the switch. For more information, see “Spanning Tree Protocol (STP)” in chapter 9,
“Configuring Advanced Features”, in the Management and Configuration Guide for your
switch.
uplink port A switch port linked to a port on another switch that is sequentially closer to the STP root
(upstream port)
device. For example, ports “A” and “B” in figure 6-12 on page 6-32 are uplink ports.
wiring closet switch Another term for an “edge” or “leaf” switch.
When single-instance spanning tree (STP) is running in a network and a
forwarding port goes down, a blocked port typically requires a period of
(2 x (forward delay) + link down detection)
6-32