Phoenix Contact FL SWITCH LM 8TX-E - 4 Rapid Spanning Tree; General Function

Rapid Spanning Tree
7278_en_04 PHOENIX CONTACT 4-1
4 Rapid Spanning Tree
4.1 General function
4.1.1 General function
Loops The Rapid/Spanning Tree Protocol (RSTP) is a standardized method
(IEEE 802.802.1w/IEEE 802.1d) that enables the use of Ethernet networks with redundant
data paths. Ethernet networks with redundant data paths form a meshed topology with
impermissible loops. Due to these loops, data packets can circulate endlessly within the
network and can also be duplicated. As a consequence, the network is usually overloaded
due to circulating data packets and thus communication is interrupted. The meshed
structure is thus replaced by a logical, deterministic path with a tree structure without loops
using the Rapid Spanning Tree algorithm. In the event of data path failure, some of the
previously disconnected connections are reconnected to ensure uninterrupted network
operation.
IEEE 802.1w The Rapid Reconfiguration Spanning Tree Protocol (RSTP) is a standardized method
(IEEE 802.1w) that enables the use of Ethernet networks with redundant data paths and
prevents the long timer-controlled switch-over times of STP. Usually, the formal term "Rapid
Reconfiguration Spanning Tree" is not used, rather just "Rapid Spanning Tree Protocol
(RSTP)".
Example:
In the following network topology (six) redundant paths have been created to ensure access
to all network devices in the event of a data path failure. These redundant paths are
impermissible loops. The RSTP protocol automatically converts this topology into a tree by
disconnecting selected ports. In this context, one of the switches is assigned the role of the
root of the tree. From this root, all other switches can be accessed by via a single data path.
Figure 4-1 Possible tree structure with Rapid Spanning Tree
1
2
3
45
72780008
Root
FL SWITCH MCS 16TX
Ord.No. 28 32 70 0
00.A0.45.1B.D2.1D
MAC
Address
1357
2468
9
11
13
15
10
12
14
16
91610 11 12 13 14 15
18234567
MODE
ACT 100 FD
US1 US2 FAIL
X19
V.24
X17
US1 GND US2 GND
X18
R1 R2
FL SWITCH MCS 16TX
Ord.No. 28 32 70 0
00.A0.45.1B.D2.1D
MAC
Address
1357
2468
9
11
13
15
10
12
14
16
91610 11 12 13 14 15
18234567
MODE
ACT 100 FD
US1 US2 FAIL
X19
V.24
X17
US1 GND US2 GND
X18
R1 R2
FL SWITCH MCS 16TX
Ord.No. 28 32 70 0
00.A0.45.1B.D2.1D
MAC
Address
1357
2468
9
11
13
15
10
12
14
16
91610 11 12 13 14 15
18234567
MODE
ACT 100 FD
US1 US2 FAIL
X19
V.24
X17
US1 GND US2 GND
X18
R1 R2
FL SWITCH 5 TX
Ord.No.2832085
US1
US2
FL SWITCH LM 8TX
Ord.-No.2832632
1
2
3
4
5
6
7
8
FL SWITCH 5 TX
Ord.No.2832085
US1
US2
FL SWITCH LM 8TX
Ord.-No.2832632
1
2
3
4
5
6
7
8