ရောက်တာ: တည်းဖြတ်မှု မူကွဲများ

=== Routers for Internet connectivity and internal use ===

Routers intended for [[Internet service provider|ISP]] and major enterprise connectivity almost invariably exchange routing information using the [[Border Gateway Protocol]] (BGP). RFC 4098<ref>[ftp://ftp.rfc-editor.org/in-notes/rfc4098.txt Terminology for Benchmarking BGP Device Convergence in the Control Plane],RFC 4098, H. Berkowitz ''et al.'',June 2005</ref> defines several types of BGP-speaking routers according to the routers' functions:

::Within an ISP: Internal to the provider's AS, such a router speaks internal BGP (IBGP) to that provider's edge routers, other intra-provider core routers, or the provider's inter-provider border routers.

::"Internet backbone:" The Internet does not have a clearly identifiable backbone, as did its predecessors. See [[default-free zone]] (DFZ). Nevertheless, it is the major ISPs' routers that make up what many would consider the core. These ISPs operate all four types of the BGP-speaking routers described here. In ISP usage, a "core" router is internal to an ISP, and used to interconnect its edge and border routers. Core routers may also have specialized functions in [[virtual private network]]s based on a combination of BGP and [[Multi-Protocol Label Switching]] (MPLS).<ref>[ftp://ftp.rfc-editor.org/in-notes/rfc2547.txt BGP/MPLS VPNs],RFC 2547, E. Rosen and Y. Rekhter, April 2004</ref>

These functions may or may not be performed through the same internal paths that the packets travel inside the router. Some of the functions may be performed through an [[Application-specific integrated circuit|ASIC]] (application-specific integrated circuit) to avoid overhead caused by multiple CPU cycles, and others may have to be performed through the CPU as these packets need special attention that cannot be handled by an ASIC.

 

The major router manufacturers include: