The total length of an MPLS label is 4 bytes (32 bits).

The TTL field in an MPLS label has the same meaning as that in an IP packet, and can prevent loops.

The S field in an MPLS label has 1 bit and is used to identify whether the label is the bottom-of-stack label. If the value is 1, the label is a penultimate-layer label.

For Ethernet and PPP packets, a label stack is located between the Layer 2 packet header and data. If a VLAN tag is available, the label stack is placed before the VLAN tag.

CQ+WFQ

PQ+WFQ

FIFO

WRR

The network protocol implementation is complex, and the O&M is difficult.

The traffic path cannot be adjusted flexibly.

The upgrade of new network services is slow.

Different vendors' devices provide similar implementation, there is less difference in operation commands, and operations are easy.