Bgp Path Selection Configuration Example - HP FlexFabric 12900E Series Configuration Manual

* >i 9.1.1.0/24
[SwitchD] display bgp routing-table ipv4 9.1.1.0
BGP local router ID: 4.4.4.4
Local AS number: 65001
Paths: 1 available, 1 best
BGP routing table information of 9.1.1.0/24:
From
Rely nexthop
Original nexthop: 10.1.3.1
OutLabel
AS-path
Origin
Attribute value : MED 0, localpref 100, pref-val 0, pre 255
State
IP precedence
QoS local ID
Traffic index
The output shows the following:
•
Switch F can send route information to Switch B and Switch C through the confederation by
establishing only an EBGP connection with Switch A.
•
Switch B and Switch D are in the same confederation, but belong to different sub-ASs. They
obtain external route information from Switch A, and generate identical BGP route entries
although they have no direct connection in between.

BGP path selection configuration example

Network requirements
As shown in
•
EBGP runs between Switch A and Switch B, and between Switch A and Switch C.
•
IBGP runs between Switch B and Switch D, and between Switch D and Switch C. OSPF is the
IGP protocol in AS 200.
Configure routing policies, making Switch D use the route 1.0.0.0/8 from Switch C as the optimal.
Figure 72 Network diagram
Vlan-int101
10.1.3.1
: 10.1.3.1 (1.1.1.1)
: 10.1.3.1
: NULL
: 100
: igp
: valid, internal-confed, best
: N/A
: N/A
: N/A
Figure 72, all switches run BGP.
Vlan-int100
AS 100
Vlan-int100
Vlan-int200
Switch A Vlan-int200
0 100
AS 200
Vlan-int300
Switch B
Vlan-int300
Vlan-int400
Switch D
Vlan-int400
Switch C
322
0 100i