Hi sir,

Actually what I have to do I have to make one system as a ipv6 router and other as a ipv6 node and I have to make a communication between them.

I do not how can I configure the default gateway or is it neccessary also to configure it?

Also we have tried with ip -6 route it just gives the global ip address set by me

While it is possible to manipulate the IPv6 routing table manually, IPv6 routers/gateways are usually autoconfigured by means of the Neighbor Discovery protocol, a part of ICMPv6.

Once you enable routing on an multihomed IPv6 host, it should start sending out Router Advertisement packets. These can also be triggered by other hosts sending Router Solicitaion queries

BTW, you will see that the next-hop value of an IPv6 route added using this mechanism will be the link-local address of the router interface. That's normal for IPv6.