## Figure 511 Sample Network for the SPF Processing Example

Links and A'—'C have a cost of 30; all other links have a cost of 10. The tunnel from Router

A to Router E has been configured with tunnel mpls traffic-eng autoroute metric 1. This means that the cost to get to Router E is 1, the cost to get to Router F is 11, and the cost to get to Router G is also 11.

But what about the costs to Routers B, C, and D? If the tunnel from Router A to Router E had a metric of 1 when the tunnel was put in the TENT list, the SPF would look something like this:

 PATH List TENT List {A,0,0} {E,1,Tunnel0} {B,30,B} {C,30,C}
 PATH List TENT List {A,0,0} {D,11,Tunnel0} {E,1,Tunnel0} {F,11,Tunnel0} {G,11,Tunnel0} {B,30,B} {C,30,C}

In the next table, {B,30,B} and {C,30,C} are removed from the TENT list because, as far as SPF is concerned, {B,21,Tunnel0} and {C,21,Tunnel0} are the shortest paths to Routers B and C.

 PATH List TENT List {A,0,0} {F,11,Tunnel0}
 {E,1,Tunnel0} {G,11,Tunnel0} {D,11,Tunnel0} {B,21,Tunnel0} {C,21,Tunnel0} {B,30,B} {C,30,C}
 PATH List TENT List {A,0,0} {E,1,Tunnel0} {D,11,Tunnel0} {B,21,Tunnel0} {C,21,Tunnel0} {F,11,Tunnel0} {G,11,Tunnel0}

Table 5-17 shows the resulting routing table.

Table 5-17 shows the resulting routing table.