[Isis-wg] Clarification needed on domain-wide prefix distribution

[Rajesh Saluja]

Folks,
I am surprised to know that there can be L1 external routes also.
I thought that only L2 routers can advertise the external routes.
If there are L1 external routes, then how does a router in L2
knows about the advertising router present in L1 domain for 
calculating the metric. I do not see equivalent of OSPF type 4
summary LSA in IISIS.
Also the domain-wide prefix distribution draft talks about 
the following types of routes.
- L1 intra-area
- L2->L1 inter-area
- L2->L1 external
- L2 intra-area
- L2 external
- L1->L2 inter-area
and each can be distinguished according to the table given
in the draft. 
 
Is there any proposal to have L1 external routes and redistribution
of such routes into L2? 

Thanks,
Rajesh