Information Technology Reference
In-Depth Information
BGP Peering Layout with Two Central Offices
Figure A-2
L1
L1
NE
L1
L1
GNE
GNE
R11
R12
NE
L1
L1
L2
L2
R9
R10
BGP AS
Central Office 1
BGP
Core AS
R7
R8
R5
R6
BGP AS
Central Office 1
R2
R1
L2
L2
L1
L1
NE
L1
L1
GNE
GNE
R3
R4
NE
L1
L1
It is a common practice to originate a CLNS default from the core network via eBGP to the
aggregation routers. The aggregation routers advertise the area addresses in their autono-
mous system to the core routers via eBGP. In the DCN environment, the goal is not optimal
routing from any to any. The purpose is to provide fault-tolerant routing from the manage-
ment stations to all the NEs. It usually isn't necessary to advertise all the NSAP prefixes
from the core autonomous systems into the aggregation domains.
