Explanation
Restrictions for IPv6 RA Guard
* The IPv6 RA Guard feature does not offer protection in environments where IPv6 traffic is tunneled.
* This feature is supported only in hardware when the ternary content addressable memory (TCAM) is programmed.
* This feature can be configured on a switch port interface in the ingress direction.
* This feature supports host mode and router mode.
* This feature is supported only in the ingress direction; it is not supported in the egress direction.
* This feature is not supported on EtherChannel and EtherChannel port members.
* This feature is not supported on trunk ports with merge mode.
* This feature is supported on auxiliary VLANs and private VLANs (PVLANs). In the case of PVLANs, primary VLAN features are inherited and merged with port features.
* Packets dropped by the IPv6 RA Guard feature can be spanned.

The policy-map COPP-7600 only rate-limit HTTP & HTTPS traffic (based on the ACL conditions) so any BGP packets will be processed in the class "class-default", which drops exceeded BGP packets. Therefore we have two ways to solve this problem:
+ Add BGP to the ACL with the statement "permit tcp any any eq bgp"
+ Configure higher value for CIR in default class as 2Mbps is too low for web traffic (http &
https)

In the configuration above, the engineer has made a mistake as he was tracking 172.16.35.6 (the backup path) instead of tracking the main path (172.16.35.2). Therefore,when he shut down the main path, the track 1 was still up so traffic still went through the main path -> it failed.
To fix this issue, we just need to correct the tracking interface of the main path.