Brocade Multi-Service IronWare Switching Configuration Guide (Supporting R05.6.00) - Manual (Page 504)

474 Multi-Service IronWare Switching Configuration Guide
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Metro Ring Protocol (MRP)
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Metro Ring Protocol (MRP)
Brocade MRP is a proprietary protocol that prevents layer 2 loops and provides fast reconvergence
in ring topologies. It is an alternative to Spanning Tree Protocol (STP) and is especially useful in
Metropolitan Area Networks (MANs) where using 802.1D STP has the following drawbacks:
• 802.1D recommends a maximum bridge diameter of seven nodes with standard timers. MRP
is capable of many more nodes than this.
• 802.1D has a slow reconvergence time, taking many seconds or even minutes. MRP can
detect and heal a break in the ring in under one second.
Figure 105 shows a simple metro ring.
FIGURE 105 MRP – normal state
The ring in this example consists of four Brocade device nodes that support MRP. Each node has
two ring interfaces and the interfaces are all in one port-based vlan. There are customer networks
utilizing the nodes and layer 2 traffic is forwarded to and from the customer networks through the
ring. Each customer interface can be in the same vlan as the ring or in a separate vlan under
control of MRP as part of a topology group.