network 192.200.10.4 0.0.0.3 area 0：

这条命令意思是这个路由器宣告他自己的网络信息，192.200.10.4是指一个网段，0.0.0.3是一个反掩码，0是精确匹配，255代表任意，不用匹配，3可以这样理解，这个网段里一共有3条主机地址。分别是192.200.10.5 192.200.10.6 192.200.10.7 也就是他指定了一个网段范围，网段范围里一共就上述的3个地址

Is the router ID required to be advertised in ospf ?

No,On Cisco routers you can explicity set it using the "router-id <ip address>" under the OSPF configuration but if you don't then it uses the loopback with the highest IP and if there are no loopbacks then the physical interface with the highest IP.

But there is no requirement for this IP to be routable ie. it simply ensures that each router has a unique id as per the RFC.

If you wanted to be able to telnet/ssh to the router id IP then yes you would need to advertise that so you can route to the IP from a remote subnet.