| 摘要 |
A system and method permits the creation of very-large metropolitan area networks MANs (200) using Layer 2 switching technology. Different groups of L2 switches are logically organized into Islands. (202, 204, 206) connected to each Island are a plurality of customers sites (212, 214, 217) and an interconnect fabric (208) couples the Islands together. The Islands cooperate to provide a Virtual Ethernet Connection VEC to each set of customer sites being coupled together. Customers identify their traffic that corresponds to a VEC by labeling or tagging it with a Customer-Equipment VLAN Identifier CE-VLAN ID. Within each Island, the CE-VLAN ID specified by the customer's traffic (and hence the corresponding VEC) is mapped to a unique MAN Provider-Equipment VLAN ID PE- VLAN ID. To prevent the formation of loops, the Islands run the Inter-MAN Control Protocol IMCP, which represents a modified version of the Multiple Spanning Tree Protocol MSTP. |
