3com S7906E 설치 설명서

 

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You can also use policy routing to route traffic over an MPLS TE tunnel. In this approach, you need to 
create a policy that specifies the MPLS TE tunnel interface as the output interface for traffic that 
matches certain criteria defined in the referenced ACL.  

This policy should be applied to the incoming interface. 

 

For more information about policy routing, refer to the QoS Configuration in the QoS Volume.  

 

You can use automatic route advertisement to advertise MPLS TE tunnel interface routes to IGPs, 
allowing traffic to be routed down MPLS TE tunnels.  

Two approaches are available to automatic route advertisement: IGP shortcut and forwarding 
adjacency.  

OSPF and IS-IS support both approaches where TE tunnels are considered point-to-point links and TE 
tunnel interfaces can be set as outgoing interfaces.  

IGP shortcut, also known as autoroute announce, considers a TE tunnel as a logical interface directly 
connected to the destination when computing IGP routes on the ingress of the TE tunnel.  

IGP shortcut and forwarding adjacency are different in that in the forwarding adjacency approach, 
routes with TE tunnel interfaces as outgoing interfaces are advertised to neighboring devices but not in 
the IGP shortcut approach. Therefore, TE tunnels are visible to other devices in the forwarding 
adjacency approach but not in the IGP shortcut approach.  

IGP shortcut and forwarding adjacency 

Router D

Router A

Router B

Router C

Router E

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As shown in 

, a TE tunnel is present between Router D and Router C. With IGP shortcut 

enabled, the ingress node Router D can use this tunnel when calculating IGP routes. This tunnel, 
however, is invisible to Router A; therefore, Router A cannot use this tunnel to reach Router C. With 
forwarding adjacency enabled, Router A can known the presence of the TE tunnel and thus forward 
traffic to Router C to Router D though this tunnel.