Luminous Preamble:
People see through this world, and people may not be significant bit of the high-ranking officials; there are a lot of ordinary people, thousands of them face life more wonderful internal, very different - in possession of brilliance in simple, innocent.
text:
Link virtualization: network as a link layer
Virtualization is a powerful resource management strategy system engineering.
Multiprotocol Label Switching (MPLS)
Through a key concept of the network from the VC - fixed-length labels can be improved lP forward speed of the router.
The goal is to use forward lP datagram routing device, but is based on technology and a fixed length virtual circuit label, the way forward data packet (not a destination IP address) according to the label by a fixed length, thus speeding up the forwarding speed ( label length of the fixed, small label space these two features to speed up the rate look-up table) .
MPLS header label acts as a virtual circuit identifier, 3 -bit reserved for experiments, a single s bit is used to indicate the end of a series of MPLS header, and a lifetime field.
A MPLS frame are only in two MPLS the transmission between the routers.
A MPLS enabled routers called Label Switch Routers often, because it by looking in the forwarding table MPLS
Tag forwarding MPLS frame, and then passes the data packets to the appropriate output interface. So, MPLS enabled routers do not extract the destination IP address does not match the longest prefix lookup is performed in the forwarding table.
Before it requires special signaling protocol to establish the forward channel the RSVP-the TE .
In this example, the router R1 to R4 are MPLS enabled, R5 and R6 are the standard IP routers.
R1 to R4 and R3 advertised it can be routed to a destination A , i.e. having MPLS label 6 forwards the frame to the destination A. Router R3 has the router R4 advertise it can be routed to the destination A , the use of the label 10 .
当一个 IP 数据报到达 R4 入口路由时，被贴上 MPLS 标签 10，发送到路由器 R3 时，R3
根据其转发表把标签换成 6，到达 R1 后，R1 转发到目的子网。