Mypower
S4100
Troubleshooting
Maipu Confidential & Proprietary Information
Page
107
of
124
If the non-directly-connected
EBGP neighbor cannot be
created, the possible cause
is: the BGP configuration
lacks the ebgp-multihop
command.
How to find out the cause:
Check whether the EBGP neighbor is created between the non-
directly-connected devices. Check whether the ebgp-multihop
command exists.
Solution:
In the BGP, use the ebgp-multihop command to increase the
IP TTL to the desired value.
Lacking the update-source
command.
How to find out the cause:
By default, the source address for the BGP to create TCP
connection is the IP address of the egress interface found in
the routing table. Check whether the loopback interface is
used to create neighbors.
Solution:
Add the update-source command in the BGP configuration.
Fault 3: The BGP route is received but it cannot be added to the core
routing table
Possible Reasons
Judging Methods and Solutions
The switch that receives BGP
routes is unavailable for the
next hop of the BGP route
How to find out the cause:
Use the show ip bgp command to check the specific route.
Check whether the gateway route exists in the next hop of
show ip route core routing table.
Solution:
Add the route that can reach the next hop of the BGP route.
If the routes learned from the
EBGP neighbor are not added
to the IP routing table, the
possible cause is that the
BGP route is suppressed.
How to find out the cause:
Check whether the route suppression function is enabled in
the BGP configuration: bgp dampening. Check whether the
specific routes are suppressed through the show ip bgp
command.
Solution:
Wait until the penalty value decreases to the limit of reuse.
Delete the route suppression configuration. Clear the jitter
statistical data.
Fault 4: After the route filtering policy is applied, BGP route is not
filtered as expected
Possible Reasons
Judging Methods and Solutions
Reset the neighbors for BGP
in the following cases:
1)
Supplement or
change the ACL
related with the
BGP
2)
Change the
weights related
with the BGP
3)
Change the
assignment list
How to find out the cause:
Check whether the neighbor is reset after the route-map policy
is modified.
Solution:
Reset the neighbor after the policy configuration is modified.
You can use the clear ip bgp to perform soft reset or hard
reset.
