10-26-2012 08:27 AM - edited 03-04-2019 05:58 PM
I am looking for some guidance with the following. I have a feeling I am missing something or that there is a better way
I have the following setup, eBGP to the same ISP, iBGP inside the AS between the routers and 6509s
I would like to do the following, lets say I have 1.1.1.0.... 1.1.6.0
These are advertised by my 6509s through BGP. I would like to balance the traffic across both of the links, so inbound/outbound traffic would be
1.1.1.0 to 3925 (primary) and 3825 as secondary
1.1.2.0 to 3825 (primary) and 3925 as secondary
I was thinking I should be able to do this using route maps
on the 3925
access-list 1 permit 1.1.1.0
access-list 1 permit 1.1.3.0
access-list 1 permit 1.1.5.0
access-list 2 permit 1.1.2.0
access-list 2 permit 1.1.4.0
access-list 2 permit 1.1.6.0
route-map subnet permit 10
match ip address 1
set as-path prepend 65401 65401
route-map subnet permit 20
match ip address 2
router bgp x.x.x.x
neighbor <core1> route-map subnet in
neighbor <core2> route-map subnet in
3825
access-list 1 permit 1.1.1.0
access-list 1 permit 1.1.3.0
access-list 1 permit 1.1.5.0
access-list 2 permit 1.1.2.0
access-list 2 permit 1.1.4.0
access-list 2 permit 1.1.6.0
route-map subnet permit 10
match ip address 2
set as-path prepend 65401 65401
route-map subnet permit 20
match ip address 1
router bgp x.x.x.x
neighbor <core1> route-map subnet in
neighbor <core2> route-map subnet in
Any help would be much appreciated
Solved! Go to Solution.
10-26-2012 08:53 AM
Hello Simon,
if you are doing eBGP to the same AS ISP you can use MED outbound to influence how traffic is routed to your network and so setting a lower or higher metric is enough.
In any case the route-map should be applied outbound to the eBGP neighbor and not inbound to the iBGP sessions.
This is the usual practice.
route-map toISP-NA permit 10
match ip address 1
set metric 1000
route-map toISP-NA permit 20
match ip address 2
set metric 500
router bgp x.x.x.x
neigh
on second border router
route-map toISP-NB permit 10
match ip address 1
set metric 500
route-map toISP-NB permit 20
match ip address 2
set metric 1000
router bgp x.x.x.x
neigh
Hope to help
Giuseppe
10-26-2012 08:53 AM
Hello Simon,
if you are doing eBGP to the same AS ISP you can use MED outbound to influence how traffic is routed to your network and so setting a lower or higher metric is enough.
In any case the route-map should be applied outbound to the eBGP neighbor and not inbound to the iBGP sessions.
This is the usual practice.
route-map toISP-NA permit 10
match ip address 1
set metric 1000
route-map toISP-NA permit 20
match ip address 2
set metric 500
router bgp x.x.x.x
neigh
on second border router
route-map toISP-NB permit 10
match ip address 1
set metric 500
route-map toISP-NB permit 20
match ip address 2
set metric 1000
router bgp x.x.x.x
neigh
Hope to help
Giuseppe
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