When a device from another vendor fails or a link fails, the LDP session alternates between Up and Down. To prevent LDP session flapping and maintain upper-layer L2VPN services, you can enable LDP to maintain a session after receiving error TCP packets.
According to RFC5036, LDP tears down a session after receiving error TCP packets. When a device from another vendor fails or a link fails, the LDP session alternates between Up and Down after processing in this way. If the LDP transmits L2VPN services, the L2VPN services will be interrupted. To prevent this problem, enable LDP to maintain a session after receiving error TCP packets. This prevents LDP session flapping and helps maintain upper-layer L2VPN services.