Traditional routing switching
CEF
fast forwarding
Process forwarding
Use the routing protocol to distribute the three-layer routing information, build the routing table
, match the routing table according to the destination address of the incoming packet, perform forwarding, and perform
a routing lookup at each hop
Route lookup based on destination address is performed at each hop and
each router must store the complete routing table
Data traffic is only passed
on the primary link. Destination address-based routing cannot balance load on links with unequal values.
Policy-based routing (PBR) is not scalable and consumes resources at the same time.
Basic MPLS functions
Use IP routing protocol and CEF exchange
to forward data packets A label in a data packet (same technology includes Frame Relay and ATM)
Designed to support a variety of Layer 3 protocols
Typically, MPLS labels correspond to the destination network segment, relying on IGP forwarding, and label distribution is related to the destination address.
The MPLS label is added between the second layer frame header and the third layer data packet header, which is a 2.5 layer protocol
Advantages
l Use a unified standard network architecture
l Better than integrating IP in ATM
l Break away from BGP core equipment
l Peer-to-peer MPLS VPN model
l Optimal data transmission (hub-spoke structure data is not optimal )
l Traffic Engineering
False Advantage
The reason for using the label switching protocol in the early days was the need for speed. For the CPU, exchanging IP packets is much slower than exchanging labels, because the former needs to read the IP address (unicast, multicast, the complexity of the same prefix and different masks), the latter only needs to read Just label
The control plane
is a set of protocols used to help create or forward data. The most important components in the control plane are routing protocols, routing tables, and other control or signaling protocols used to provide the data plane.
Data plane
The packet forwarding path through a router or switch. Packet switching---or the forwarding layer---is currently built into the ASIC, so to speed up packet forwarding, under the current hardware architecture, labels have no advantage
Using a unified standard network architecture
, MPLS can transmit IPv4, IPv6, Ethernet, HDLC, PPP, and other Layer 2 technologies. This feature of transmitting any Layer 2 frame in the MPLS backbone network is called MPLS arbitrary transmission. (AToM)