25.02.2013 Views

TCP/IP Tutorial and Technical Overview - IBM Redbooks

TCP/IP Tutorial and Technical Overview - IBM Redbooks

TCP/IP Tutorial and Technical Overview - IBM Redbooks

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

ecause AS 2 does not know this aggregate contains networks located within<br />

AS 3.<br />

5.9.7 BGP confederations<br />

BGP requires that all speakers within a single AS have a fully meshed set of<br />

IBGP connections. This can be a scaling problem in networks containing a large<br />

number of IBGP peers. The use of BGP confederations addresses this problem.<br />

A BGP confederation creates a set of autonomous systems that represent a<br />

single AS to peers external to the confederation. This removes the full mesh<br />

requirement <strong>and</strong> reduces management complexity.<br />

Figure 5-28 illustrates the operation of a BGP confederation. In this sample<br />

network, AS 1 contains eight BGP speakers. A st<strong>and</strong>ard BGP network would<br />

require 28 IBGP sessions to fully mesh the speakers.<br />

BGP<br />

R2<br />

BGP<br />

R1<br />

AS 100<br />

BGP<br />

R9<br />

AS 3<br />

EBGP<br />

BGP<br />

R3<br />

Figure 5-28 BGP confederations<br />

230 <strong>TCP</strong>/<strong>IP</strong> <strong>Tutorial</strong> <strong>and</strong> <strong>Technical</strong> <strong>Overview</strong><br />

BGP<br />

R2<br />

EBGP<br />

AS 1<br />

AS 101<br />

BGP<br />

R1<br />

BGP<br />

R7<br />

EBGP<br />

BGP<br />

R6<br />

AS 102<br />

BGP<br />

R8<br />

BGP<br />

R10<br />

AS 2

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!