Service-based transport classes for mapping services to tunnels

1. A method comprising:

receiving, by processing circuitry of a first network device and over a routing protocol session between the first network device and a second network device, a single routing protocol message specifying: first data indicating one or more underlay tunnels of a first administrative domain configured to support a service route, and second data indicating a route target to cause routers receiving the service route to import the service route to use the one or more underlay tunnels, the service route being a logical route for transporting network traffic from a service host device that generates network traffic associated with a first network service to a customer edge device that receives the network traffic associated with the first network service, wherein the first network service comprises one of a plurality of network services, and wherein the first network device comprises a border node at a border of the first administrative domain and a second administrative domain;

storing, by the processing circuitry and based on the first data and the second data, data indicative of a first transport class of a plurality of transport classes, wherein the first transport class is a service-specific group comprising the route target and specifying the one or more underlay tunnels of the first administrative domain as belonging to the service-specific group, and wherein the route target of the first transport class is different from route targets of each other transport class of the plurality of transport classes;

storing, by the processing circuitry, an association between the service route and the first transport class to enable stitching together the one or more underlay tunnels of the first administrative domain with one or more underlay tunnels of the second administrative domain that also belong to the service-specific group;

receiving, by the processing circuitry, the network traffic associated with the first network service via one or more underlay tunnels of the second administrative domain;

identifying, by the processing circuitry, the network traffic associated with the first network service as being associated with the service route for the first network service of the plurality of network services; and

forwarding, by the processing circuitry and based on the association between the service route and the first transport class of the plurality of transport classes, the network traffic associated with the first network service of the plurality of network services along the one or more underlay tunnels of the first administrative domain specified by the first transport class.

2. The method of claim 1 , further comprising:

receiving, by the processing circuitry and from a second network device prior to storing the association between the service route and the first transport class, a second routing protocol message specifying the service route for the first network service of the plurality of network services, wherein the service route specifies a mapping community; and

determining, by the processing circuitry, a correspondence of the mapping community of the service route to a transport Routing Information Base (RIB) of the first transport class of the plurality of transport classes,

wherein storing the association comprises storing, based on the correspondence of the mapping community of the service route to the transport RIB of the first transport class of the plurality of transport classes, the association between the service route and the first transport class of the plurality of transport classes.

3. The method of claim 2 ,

wherein storing, based on the correspondence of the mapping community of the service route to the route target of the first transport class of the plurality of transport classes, the association between the service route and the first transport class of the plurality of transport classes comprises:

installing a transport route for the service route in a first transport routing information base (RIB) of a plurality of transport RIBs, wherein each transport RIB of the plurality of transport RIBs corresponds to a transport class of the plurality of transport classes, and

wherein forwarding, based on the association between the service route and the first transport class of the plurality of transport classes, the network traffic associated with the first network service of the plurality of network services along the one or more underlay tunnels specified by the first transport class comprises:

forwarding, based on the transport route for the service route specified by the first transport RIB of the plurality of transport RIBs, the network traffic associated with the first network service of the plurality of network services to a protocol next hop (PNH) for the first network service of the plurality of network services.

4. The method of claim 3 , wherein forwarding the network traffic associated with the first network service of the plurality of network services to the PNH for the first network service of the plurality of network services comprises:

obtaining, from a forwarding information base (FIB), a next hop for the PNH; and

forwarding the network traffic associated with the first network service of the plurality of network services to the next hop for the PNH.

5. The method of claim 1 , wherein the single routing protocol message comprises a Border Gateway Protocol (BGP) message.

6. The method of claim 1 , further comprising in response to receiving the single routing protocol message, outputting, by the processing circuitry and to a second network device, a second routing protocol message specifying the route target and the one or more underlay tunnels.

7. The method of claim 1 ,

wherein the single routing protocol message further specifies third data indicating a route distinguisher, and

wherein the first transport class comprises the route distinguisher and the route target and specifies the one or more underlay tunnels.

8. The method of claim 1 ,

wherein the single routing protocol message further specifies third data indicating a color of the one or more underlay tunnels, and

wherein the first transport class comprises the route target and specifies the one or more underlay tunnels and the color of the one or more underlay tunnels.

9. The method of claim 1 , further comprising:

receiving, by the processing circuitry, fallback resolution information specifying an order of application of the one or more underlay tunnels specified by the first transport class.

10. The network device of claim 9 ,

wherein the single routing protocol message further specifies third data indicating a route distinguisher, and

wherein the first transport class comprises the route distinguisher and the route target and specifies the one or more underlay tunnels.

11. The network device of claim 9 ,

wherein the single routing protocol message further specifies third data indicating a color of the one or more underlay tunnels, and

wherein the first transport class comprises the route target and specifies the one or more underlay tunnels and the color of the one or more underlay tunnels.

12. A network device comprising processing circuitry, the network device configured to:

receive a single routing protocol message specifying: first data indicating one or more underlay tunnels configured to support a service route, and second data indicating a route target to cause routers receiving the service route to import the service route to use the one or more underlay tunnels, the service route being a logical route for transporting network traffic associated with a first network service to a customer edge device that receives the network traffic associated with the first network service, wherein the first network service comprises one of a plurality of network services;

store, based on the first data and the second data, data indicative of a first transport class of a plurality of transport classes, wherein the first transport class is a service-specific group comprising the route target and specifying the one or more underlay tunnels that belong to the service-specific group, and wherein the route target of the first transport class is different from route targets of each other transport class of the plurality of transport classes;

store an association between the service route and the first transport class to enable stitching together the one or more underlay tunnels of the first administrative domain with one or more underlay tunnels of the second administrative domain;

receive the network traffic associated with the first network service via one or more underlay tunnels of the second administrative domain;

identify the network traffic associated with the first network service as being associated with the service route for the first network service of the plurality of network services; and

forward, based on the association between the service route and the first transport class of the plurality of transport classes, the network traffic associated with the first network service of the plurality of network services along the one or more underlay tunnels specified by the first transport class.

13. The network device of claim 12 , wherein the network device is further configured to:

receive, from a second network device prior to storing the association between the service route and the first transport class, a second routing protocol message specifying the service route for the first network service of the plurality of network services, wherein the service route specifies a mapping community;

determine a correspondence of the mapping community of the service route to a transport Routing Information Base (RIB) of the first transport class of the plurality of transport classes; and

wherein to the association comprises to store, based on the correspondence of the mapping community of the service route to the transport RIB, the association between the service route and the first transport class of the plurality of transport classes.

14. The network device of claim 13 ,

wherein to store, based on the correspondence of the mapping community of the service route to the route target of the first transport class of the plurality of transport classes, the association between the service route and the first transport class of the plurality of transport classes, the network device is configured to:

install a transport route for the service route in a first transport routing information base (RIB) of a plurality of transport RIBs, wherein each transport RIB of the plurality of transport RIBs corresponds to a transport class of the plurality of transport classes, and

wherein to forward, based on the association between the service route and the first transport class of the plurality of transport classes, the network traffic associated with the first network service of the plurality of network services along the one or more underlay tunnels specified by the first transport class, the network device is configured to:

forward, based on the transport route for the service route specified by the first transport RIB of the plurality of transport RIBs, the network traffic associated with the first network service of the plurality of network services to a protocol next hop (PNH) for the first network service of the plurality of network services.

15. The network device of claim 12 ,

wherein the first network device comprises a border node at a border of a first administrative domain and a second administrative domain,

wherein the one or more underlay tunnels comprise one or more underlay tunnels of the first administrative domain, wherein receiving the network traffic associated with the first network service comprises receiving the network traffic via one or more underlay tunnels of the second administrative domain, and

wherein storing the association between the service route and the first transport class enables stitching together the one or more underlay tunnels of the first administrative domain with one or more underlay tunnels of the second administrative domain.

16. A non-transitory computer-readable medium comprising instructions that, when executed, are configured to cause processing circuitry of a border node capable of being positioned at a border of a first administrative domain and a second administrative domain to:

receive a transport route specifying: first data indicating one or more underlay tunnels configured to support a service route, and second data indicating a route target to cause routers receiving the service route to import the service route to use the one or more underlay tunnels, the service route being a logical route for transporting network traffic associated with a first network service to a customer edge device that receives the network traffic associated with the first network service, wherein the first network service comprises one of a plurality of network services;

store, based on the first data and the second data, data indicative of a first transport class of a plurality of transport classes, wherein the first transport class is a service-specific group comprising the route target and specifying the one or more underlay tunnels that belong to the service-specific group, and wherein the route target of the first transport class is different from route targets of each other transport class of the plurality of transport classes;

store an association between the service route and the first transport class to enable stitching together the one or more underlay tunnels of the first administrative domain with one or more underlay tunnels of the second administrative domain;

receive the network traffic associated with the first network service via one or more underlay tunnels of the second administrative domain;

identify the network traffic associated with the first network service as being associated with the service route for the first network service of the plurality of network services; and

forward, based on the association between the service route and the first transport class of the plurality of transport classes, the network traffic associated with the first network service of the plurality of network services along the one or more underlay tunnels specified by the first transport class.

17. The non-transitory computer-readable medium of claim 16 , wherein the transport route comprises a leaked transport route,

wherein the one or more underlay tunnels comprise one or more underlay tunnels of the first administrative domain, wherein receiving the network traffic associated with the first network service comprises receiving the network traffic via one or more underlay tunnels of the second administrative domain, and

wherein the instructions to cause the processing circuitry to store the association between the service route and the first transport class comprise instructions to stitch together the one or more underlay tunnels of the first administrative domain with one or more underlay tunnels of the second administrative domain.