Transmission and storage of routing path information and routing topology information using a single routing protocol
Methods, systems, and devices are described for transmitting and storing routing path information and routing topology information using a single protocol. In particular embodiments, routing path information for an exterior gateway protocol (“EGP”) network such as a border gateway protocol (“BGP”) network is transmitted throughout an interior gateway protocol (“IGP”) network using IGP messages such as open-shortest-path-first (“OSPF”) or intermediate state to intermediates state (“IS-IS”) messages. The IGP networks may transmit and store the BGP information using type length values (TLVs). As a result, network areas running an IGP may maintain BGP information throughout the network area without the overhead of an iBGP mesh and related message-passing.
1. A network environment, comprising:
an edge router configured to:
receive a border gateway protocol (“BGP”) message;
extract BGP information from the BGP message;
transform the BGP information into transformed BGP information for inclusion in an Interior Gateway Protocol (“IGP”) message; and
transmit, within a local network domain, the IGP message containing the transformed BGP information; and
an interior router configured to:
receive the IGP message containing the transformed BGP information;
store the transformed BGP information in an IGP database; and
calculate a best routing path based at least in part on the transformed BGP information;
wherein the IGP is a link-state protocol.
2. The network environment of claim 1 , wherein the IGP is an implementation of the open shortest path first (OSPF) routing protocol or the Intermediate System to Intermediate System (“IS-IS”) routing protocol, and the transformed BGP information is embedded within a type length value (“TLV”) element.
3. The network environment of claim 1 , wherein the interior router is further configured to transmit a second IGP message containing the transformed BGP information, and wherein the interior router is not directly connected to all other interior routers in the network environment.
4. The network environment of claim 1 , wherein the edge router is further configured to generate the IGP message containing the transformed BGP information based on communications with a local virtual internal BGP neighbor that supplies a set of BGP routes into a consolidated set of TLV elements.
5. The network environment of claim 1 , wherein the edge router is one of a group of edge routers and the interior router is one of a group of interior routers, wherein the edge routers run both the BGP and the IGP, and wherein the interior routers run the IGP without running the BGP.
6. The network environment of claim 1 , further comprising a second edge router configured to:
receive a second IGP message containing the transformed BGP information;
extract the transformed BGP information from the second IGP message;
derive the BGP information from the transformed BGP information;
generate a second BGP message containing the BGP information; and
transmit the second BGP message outside the local network domain.
7. A method, comprising:
receiving, at a first routing device, a first message containing routing path information for a first network;
extracting from the first message, at the first routing device, the routing path information for the first network;
generating a second message comprising:
the routing path information for the first network; and
routing topology information for a second network; and
transmitting the second message over the second network,
wherein the second message is received at a second routing device communicating over the second network and the routing path information for the first network and the routing topology information for the second network are used by the second routing device in calculating a best routing path.
8. The method of claim 7 , further comprising storing, in a first routing database on the first routing device, the routing path information for the first network, wherein the first routing database also contains routing topology information for the second network.
9. The method of claim 7 , wherein the first message is an exterior gateway protocol (“EGP”) message and the second message is an interior gateway protocol (“IGP”) message.
10. The method of claim 9 , wherein the EGP message is a border gateway protocol (“BGP”) message.
11. The method of claim 7 , wherein the second routing device stores the routing path information for the first network in a second routing database.
12. The method of claim 11 , wherein the second routing database is a link-state protocol routing database.
13. The method of claim 7 , wherein the first network comprises a network of autonomous systems and the second network comprises a network within an autonomous system.
14. The method of claim 7 , wherein the second message comprises a type length value (“TLV”) element containing the routing path information for the first network.
15. The method of claim 7 , wherein the routing path information for the first network comprises network layer reachability information (“NLRI”) and path update information.
16. The method of claim 7 , wherein the first network comprises a number of interior routing devices that are not all directly connected to one another.
17. A routing device comprising code that when executed causes the routing device to:
receive a border gateway protocol (“BGP”) message;
extract BGP information from the BGP message;
transform the BGP information into a format compatible with an Interior Gateway Protocol (“IGP”); and
transmit an IGP message containing the transformed BGP information, wherein the IGP message is configured for receipt by a second routing device and use by the second routing device of the transformed BGP information in calculating a best routing path.
18. The routing device of claim 17 , wherein the IGP message comprises a type-length value (“TLV”) containing the BGP information.
19. The routing device of claim 17 , further comprising code that when executed causes the routing device to store the BGP information in an IGP routing database along with IGP routing information.
20. The routing device of claim 17 , wherein the BGP information comprises network layer reachability information (“NLRI”) and best-path information.