This section discusses operational experience with BGP and BGP-4.
BGP has been used in the production environment since 1989, BGP-4 since 1993. This use involves at least two of the implementations listed above. Production use of BGP includes utilization of all significant features of the protocol. The present production environment, where BGP is used as the inter-autonomous system routing protocol, is highly heterogeneous. In terms of the link bandwidth it varies from 28 Kbits/sec to 150 Mbits/sec. In terms of the actual routes that run BGP it ranges from a relatively slow performance PC/RT to a very high performance RISC based CPUs, and includes both the special purpose routers and the general purpose workstations running UNIX.
In terms of the actual topologies it varies from a very sparse (spanning tree of ICM) to a quite dense (NSFNET backbone).
At the time of this writing BGP-4 is used as an inter-autonomous system routing protocol between ALL significant autonomous systems, including, but by all means not limited to: Alternet, ANS, Ebone, ICM, IIJ, MCI, NSFNET, and Sprint. The smallest know backbone consists of one router, whereas the largest contains nearly 90 BGP speakers. All together, there are several hundred known BGP speaking routers.
BGP is used both for the exchange of routing information between a transit and a stub autonomous system, and for the exchange of routing information between multiple transit autonomous systems. There is no distinction between sites historically considered backbones vs "regional" networks.
Within most transit networks, BGP is used as the exclusive carrier of the exterior routing information. At the time of this writing within a few sites use BGP in conjunction with an interior routing protocol to carry exterior routing information.
The full set of exterior routes that is carried by BGP is well over 20,000 aggregate entries representing several times that number of connected networks.
Operational experience described above involved multi-vendor deployment (cisco, and "gated").
Specific details of the operational experience with BGP in Alternet, ICM and Ebone were presented at the Twenty-fifth IETF meeting (Toronto, Canada) by Peter Lothberg (Ebone), Andrew Partan (Alternet) and Paul Traina (cisco).
Operational experience with BGP exercised all basic features of the protocol, including authentication, routing loop suppression and the new features of BGP-4, enhanced metrics and route aggregation.
Bandwidth consumed by BGP has been measured at the interconnection points between CA*Net and T1 NSFNET Backbone. The results of these measurements were presented by Dennis Ferguson during the Twenty- first IETF, and are available from the IETF Proceedings. These results showed clear superiority of BGP as compared with EGP in the area of bandwidth consumed by the protocol. Observations on the CA*Net by Dennis Ferguson, and on the T1 NSFNET Backbone by Susan Hares confirmed clear superiority of the BGP protocol family as compared with EGP in the area of CPU requirements.