关于北京联通 IPv6 Delegation 设置

我的网络拓扑：

pc -> 软路由 -> 光猫(非桥接) 

我可以从光猫上看到联通给下发了网络前缀：

2408:8207:xxxx:xxxx::/60 

但是我的软路由通过 dhcpv6 client 可以拿到 ipv6 地址，但是拿不到 ipv6 prefix

ifstatus wan6 { "up": true, "pending": false, "available": true, "autostart": true, "dynamic": false, "uptime": 66334, "l3_device": "eth0", "proto": "dhcpv6", "device": "eth0", "metric": 0, "dns_metric": 0, "delegation": true, "ipv4-address": [ ], "ipv6-address": [ { "address": "2408:8207:24c7:57c0:xxx:xxxx:xxxx", "mask": 64, "preferred": 136922, "valid": 223322 } ], "ipv6-prefix": [ ], "ipv6-prefix-assignment": [ ], "route": [ { "target": "2408:8207:24c7:57c0::", "mask": 64, "nexthop": "::", "metric": 256, "valid": 22332, "source": "::/0" }, { "target": "::", "mask": 0, "nexthop": "fe80::1", "metric": 512, "valid": 1709, "source": "2408:8207:24c7:57c0:dea6:xxx:xxxx:xxxx/64" } ], "dns-server": [ "2408:8207:24c7:57c0:a23e:6bff:fea0:a2a7", "fe80::a23e:6bff:fea0:a2a7", "2408:8000:1010:1::8", "2408:8000:1010:2::8" ], "dns-search": [ ], "neighbors": [ ], "inactive": { "ipv4-address": [ ], "ipv6-address": [ ], "route": [ ], "dns-server": [ ], "dns-search": [ ], "neighbors": [ ] }, "data": { "passthru": "001700102408820724c757c0a23ea0a2a7" } } 

初步猜测是光猫的 dhcpv6 不支持下发 ipv6 delegation，或者我的 wan6 接口需要一些特殊配置

有熟悉的兄弟望指点，谢谢！