In an operator's MPLSVPN network, there are two devices, PE1 and PE2, for MPLSVPN data forwarding. PE1 receives a 172.16.1.0/24 private network route from the client, and transforms it into a VPNv4 route on PE1 and assigns labels. Released to PE2 as 1027. The outgoing label of the MPLSLSR-ID from PE2 to PE1 is 1025.
When the client on PE2 accesses 172.16.1.0/24, the inner and outer labels of the frame sent by PE2 should be the combination of the following options?

A certain park deployed both IPv4 and IPv6 networks for service testing, and IS-IS was run to achieve network interconnection. IS-IS routing protocol has good scalability and is widely used in existing networks.
Regarding IS-IS scalability, which of the following statements are correct? (Multiple choice)

Qing technology is a technology that expands the VLAN space. It achieves the function of expanding the VLAN space by adding a layer of 8D2.1Q Tag on the basis of the 8Q2.12 tag message.
Which of the following statements about qinq is wrong?

What is the value of OSPF and BFD linkage?

What is the most effective way to view device alarms through CLI?