Bgp Path Selection Configuration Example - HPE 5800 Series Configuration Manual

[SwitchD] display bgp routing-table
Total Number of Routes: 1
BGP Local router ID is 4.4.4.4
Status codes: * - valid, ^ - VPNv4 best, > - best, d - damped,
*>i
[SwitchD] display bgp routing-table 9.1.1.0
BGP local router ID : 4.4.4.4
Local AS number : 65001
Paths:
BGP routing table entry information of 9.1.1.0/24:
From
Relay Nexthop
Original nexthop: 10.1.3.1
AS-path
Origin
Attribute value : MED 0, localpref 100, pref-val 0, pre 255
State
Not advertised to any peers yet
The output indicates 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 the same BGP route entries; it
seems like that they reside in the same AS although they have no direct connection in
between.

BGP path selection configuration example

Network requirements
•
In Figure
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.
h - history,
Origin : i - IGP, e - EGP, ? - incomplete
Network
9.1.1.0/24 10.1.3.1
1 available, 1 best
: 10.1.3.1 (1.1.1.1)
: 0.0.0.0
: 100
: igp
: valid, internal, best,
78, all switches run BGP. EBGP runs between Switch A and Switch B, and between
i - internal, s - suppressed, S - Stale
NextHop MED
0
236
LocPrf PrefVal Path/Ogn
100 0 100i