No relevant resource is found in the selected language.

This site uses cookies. By continuing to browse the site you are agreeing to our use of cookies. Read our privacy policy>Search


To have a better experience, please upgrade your IE browser.


Configuration Guide - IP Unicast Routing

CloudEngine 12800 and 12800E V200R002C50

This document describes the configurations of IP Unicast Routing, including IP Routing, Static Route, RIP, RIPng, OSPF, OSPFv3, IPv4 IS-IS, IPv6 IS-IS, BGP, Routing Policy, and PBR.

Rate and give feedback:
Huawei uses machine translation combined with human proofreading to translate this document to different languages in order to help you better understand the content of this document. Note: Even the most advanced machine translation cannot match the quality of professional translators. Huawei shall not bear any responsibility for translation accuracy and it is recommended that you refer to the English document (a link for which has been provided).
BGP Confederation

BGP Confederation

In addition to a route reflector, the confederation is another method that reduces the number of IBGP connections in an AS. A confederation divides an AS into sub-ASs. Full-mesh IBGP connections are established in each sub-AS. EBGP connections are established between sub-ASs. ASs outside a confederation still consider the confederation as an AS. After a confederation divides an AS into sub-ASs, it assigns a confederation ID (the AS number) to each router within the AS. This brings two benefits. First, original IBGP attributes are retained, including the Local_Pref attribute, MED attribute, and Next_Hop attribute. Secondly, confederation-related attributes are automatically deleted when being advertised outside a confederation. Therefore, the administrator does not need to configure the rules for filtering information such as sub-AS numbers at the egress of a confederation.

Figure 9-7 Networking diagram of a confederation

As shown in Figure 9-7, AS 100 is divided into three sub-ASs after a confederation is configured: AS65001, AS65002, and AS65003. The AS number AS 100 is used as the confederation ID. The number of IBGP connections in AS 100 is then reduced from 10 to 4, which simplifies the device configuration and reduces the loads on the network and CPU. In addition, BGP devices outside AS 100 only know the existence of AS 100 but not the confederation within AS 100. Therefore, the confederation does not increase the CPU load.

Comparisons Between a Route Reflector and a Confederation

Table 9-3 compares a route reflector and a confederation in terms of the configuration, device connection, and applications.

Table 9-3 Comparisons between a route reflector and a confederation
Route Reflector Confederation
Retains the existing network topology and ensures compatibility. Requires the logical topology to be changed.
Requires only a route reflector to be configured because clients do not need to know that they are clients of a route reflector. Requires all devices to be reconfigured.
Requires full-mesh connections between clusters. Does not require full-mesh connections between sub-ASs of a confederation because the sub-ASs are special EBGP peers.
Applies to medium and large networks. Applies to large networks.
Updated: 2019-03-21

Document ID: EDOC1000166601

Views: 274514

Downloads: 161

Average rating:
This Document Applies to these Products

Related Version

Related Documents

Previous Next