373
# Configure Switch B.
<SwitchB> system-view
[SwitchB] bgp 200
[SwitchB-bgp] router-id 2.2.2.2
[SwitchB-bgp] peer 1.1.2.2 as-number 300
# Configure Switch C.
<SwitchC> system-view
[SwitchC] bgp 300
[SwitchC-bgp] router-id 3.3.3.3
[SwitchC-bgp] peer 1.1.1.1 as-number 100
[SwitchC-bgp] peer 1.1.2.1 as-number 200
[SwitchC-bgp] peer 1.1.3.2 as-number 400
# Configure Switch D.
<SwitchD> system-view
[SwitchD] bgp 400
[SwitchD-bgp] router-id 4.4.4.4
[SwitchD-bgp] peer 1.1.3.1 as-number 300
[SwitchD-bgp] quit
# On Switch A, inject routes 4.4.4.4/24, 5.5.5.5/24, and 6.6.6.6/24 to BGP.
[SwitchA-bgp] network 4.4.4.4 24
[SwitchA-bgp] network 5.5.5.5 24
[SwitchA-bgp] network 6.6.6.6 24
# On Switch B, inject routes 7.7.7.7/24, 8.8.8.8/24, and 9.9.9.9/24 to BGP.
[SwitchB-bgp] network 7.7.7.7 24
[SwitchB-bgp] network 8.8.8.8 24
[SwitchB-bgp] network 9.9.9.9 24
# Display the BGP routing table information of Switch D.
[SwitchD-bgp] display bgp routing-table
Total Number of Routes: 6
BGP Local router ID is 4.4.4.4
Status codes: * - valid, > - best, d - damped,
h - history, i - internal, s - suppressed, S - Stale
Origin : i - IGP, e - EGP, ? - incomplete
Network NextHop MED LocPrf PrefVal Path/Ogn
*> 4.4.4.0/24 1.1.3.1 0 300 100i
*> 5.5.5.0/24 1.1.3.1 0 300 100i
*> 6.6.6.0/24 1.1.3.1 0 300 100i
*> 7.7.7.0/24 1.1.3.1 0 300 200i
*> 8.8.8.0/24 1.1.3.1 0 300 200i
*> 9.9.9.0/24 1.1.3.1 0 300 200i
The output shows that Switch D has learned routes 4.4.4.0/24, 5.5.5.0/24, and 6.6.6.0/24
from AS 100 and 7.7.7.0/24, 8.8.8.0/24, and 9.9.9.0/24 from AS 200.
3.
Configure Switch D to reject routes from AS 200:
# Configure AS path list 1.