| Acronym/Concept | Description |
|---|---|
| AS | see Autonomous System. |
| Autonomous System | a routing domain that is under one administrative authority, and which implements its own routing policies. Key concept in BGP. |
| BGP | Border Gateway Protocol. |
| Bootstrap Router | A PIM-SM router that chooses the RPs for a domain from amongst a set of candidate RPs. |
| BSR | See Bootstrap Router. |
| Candidate RP | A PIM-SM router that is configured to be a candidate to be an RP. The Bootstrap Router will then choose the RPs from the set of candidates. |
| Dynamic Route | A route learned from another router via a routing protocol such as RIP or BGP. |
| EGP | see Exterior Gateway Protocol. |
| Exterior Gateway Protocol1) | a routing protocol used to route between Autonomous Systems. The main example is BGP. |
| FEA | Forwarding Engine Abstraction |
| FIB | Forwarding Information Base |
| IGMP | Internet Group Management Protocol. |
| IGP | see Interior Gateway Protocol. |
| Interior Gateway Protocol | a routing protocol used to route within an Autonomous System. Examples include RIP, OSPF and IS-IS. |
| Live CD | A CD-ROM that is bootable. In the context of XORP, the Live CD can be used to produce a low-cost router without needing to install any software. |
| MFC | Multicast Forwarding Cache: another name for an entry in the multicast forwarding engine typically used on UNIX systems). |
| MFEA | Multicast Forwarding Engine Abstraction |
| MLD/IGMP | Multicast Listener Discovery/Internet Group Management Protocol |
| MRIB | See Multicast RIB. |
| Multicast RIB | the part of the RIB that holds multicast routes. These are not directly used for forwarding, but instead are used by multicast routing protocols such as PIM-SM to perform RPF checks when building the multicast distibution tree. |
| OSPF | See Open Shortest Path First. |
| Open Shortest Path First | an IGP routing protocol based on a link-state algorithm. Used to route within medium to large networks. |
| PIM-SM | Protocol Independent Multicast, Sparse Mode. |
| Rendezvous Point | A router used in PIM-SM as part of the rendezvous process by which new senders are grafted on to the multicast tree. |
| Reverse Path Forwarding | many multicast routing protocols such as PIM-SM build a multicast distribution tree based on the best route back from each receiver to the source, hence multicast packets will be forwarded along the reverse of the path to the source. |
| RIB | See Routing Information Base. |
| RIP | Routing Information Protocol. |
| Routing Information Base | the collection of routes learned from all the dynamic routing protocols running on the router. Subdivided into a Unicast RIB for unicast routes and a Multicast RIB. |
| RP | See Rendezvous Point. |
| RPF | See Reverse Path Forwarding. |
| Static Route | A route that has been manually configured on the router. |
| VRRP | Virtual Router Redundancy Protocol. |
| xorpsh | XORP command shell. |
| xorp_rtrmgr | XORP router manager process. |