what is use of dev_queue_xmit_nit?

[linux lover <linux.lover2004@xxxxxxxxx>]

Hello all,
       I want to know what is use of dev_queue_xmit_nit function in
dev.c file? Also why it calls following statement
                        ptype->func(skb2, skb->dev, ptype);
Also why skb2 is created by cloning skb? Acually i trace TCP packets
and found that control goes from neigh_resolve_output to directly
dev_queue_xmit_nit and then to HW driver 8139too.c? I want to know why
it not goes from dev_queue_xmit? I place printk statments and found
after dev_queue_xmit_nit control moves to network interface driver?
Help to understand the control  packet path.
Thanks in advance.
linux_lover