05-19-2017 10:22 AM - edited 03-08-2019 10:39 AM
Hello all,
I have two ASR routers that I use for my edge router. Each router has one connection each to the same ISP on different routers from the ISP. Each router is set up as a router on a stick with seven sub interfaces. Each interface is a different customer. I use VRF's to separate traffic and no RD's are configured. Routing is currently done with static routing. There are static routes in the global table that point to the subinterface then that same static route is also created in that vrf. I point a static default route to the ISP and a floating static route between the two ASR's for failover in the global routing table. Each vrf also has a default and floating static route that are exported to the global table by adding the "global" option at the end of the static route command. Then The ISP uses static routes to get back to individual subnets. I have a requirement to switch to BGP. When I switch to BGP is there anything special that I need to do with the VRF's that already configured to make sure that routing continues? I'm planning to advertise routes into BGP with redistribute static. Here is what I have for a config so far:
router bgp xxx 39 |
no synchronization |
bgp log-neighbor-changes |
neighbor x.x.x.126 remote-as 39 |
neighbor x.x.x.126 description IBGP R1 |
neighbor x.x.x.126 update-source loopback 7 |
neighbor x.x.x.126 next-hop-self |
neighbor x.x.x.126 soft-reconfiguration inbound |
neighbor x.x.x.225 remote-as 64 |
neighbor x.x.x.225 description EBGP to ISP |
neighbor x.x.x.225 route-map Filter_Routes in |
neighbor x.x.x.225 route-map Filter_Routes out |
neighbor x.x.x.225 soft-reconfiguration inbound |
bgp default local-preference 200 |
redistribute static |
neighbor x.x.x.225 password |
! |
ip as-path access-list 200 permit ^64$ |
ip as-path access-list 250 permit ^$ |
ip prefix-list accept_default_route seq 5 permit 0.0.0.0/0 le 32 |
! |
ip bgp-community new-format |
! |
route-map Filter_Routes permit 10 |
match as-path 200 |
match ip address prefix-list accept-default-route |
exit |
route-map Filter_Routes permit 20 |
Match as-path 250 |
router bgp 39 |
no synchronization |
bgp log-neighbor-changes |
neighbor x.x.x.125 remote-as 39 |
neighbor x.x.x.125 description IBGP to R2 |
neighbor x.x.x.125 update-source loopback 7 |
neighbor x.x.x.125 next-hop-self |
neighbor x.x.x.125 soft-reconfiguration inbound |
neighbor x.x.x.225 remote-as 64 |
neighbor x.x.x.225 description EBGP to ISP |
neighbor x.x.x.225 ebgp multi-hop 5 |
neighbor x.x.x.225 route-map Filter_Routes in |
neighbor x.x.x.225 route-map Filter_Routes out |
neighbor x.x.x.225 route-map Prepend_AS39 |
neighbor x.x.x.225 soft-reconfiguration inbound |
bgp default local-preference 50 |
redistribute static |
neighbor x.x.x.225 password |
! |
ip as-path access-list 200 permit ^64$ |
ip as-path access-list 250 permit ^$ |
ip prefix-list accept_default_route seq 5 permit 0.0.0.0/0 le 32 |
! |
ip bgp-communtiy new-format |
! |
route-map Prepend_AS39 |
set as-path prepend 39 39 39 |
route-map Filter_Routes permit 10 |
match as-path 200 |
match ip address prefix-list accept-default-route |
exit |
route-map Filter_Routes permit 20 |
Match as-path 250 |
An example of a current static route to Customer A with a global and vrf static route:
ip route x.x.45.0 255.255.254.0 TenGigabitEthernet0/0/0.3 x.x.x.129
ip route vrf custA-vrf x.x.45.0 255.255.254.0 x.x.x.129
05-20-2017 05:40 PM
Hi
If you are going to advertise the customer subnets through BGP and using VRFs, you need to create individual address families for each VRF and into each one configure the peerings and other arguments
basic example:
router bgp 100
no sync
no auto
no bgp default ipv4-unicast
address-family ipv4 vrf A
neighbor 1.1.1.1 remote 101
neighbor 1.1.1.1 activate
<other arguments>
address-family ipv4 vrf B
neighbor 1.1.1.1 remote 101
neighbor 1.1.1.1 activate
<other arguments>
address-family ipv4 vrf C
neighbor 1.1.1.1 remote 101
neighbor 1.1.1.1 activate
<other arguments>
It is just and example you should adjust it to your requirements.
Hope it is useful
:-)
05-22-2017 06:21 AM
Thanks Julio. Would this be the case even if the subnets are in the global table with the static routes?
Corey
05-22-2017 07:10 AM
Hi
You are welcome, no if the subnets are in the global routing it should be included on the normal IPv4 family address.
05-22-2017 11:32 AM
Hi corey.burden,
If you want to get rid off static routing completely then you can configure Intervrf routing or vrf to default or vice versa by using BGP. This will give you more granular control over routing.
05-23-2017 06:52 AM
There is not a requirement to remove static routing at this point and Intrevrf routing would violate our security requirement so that wouldn't work anyway. But thanks for that information.
05-23-2017 06:48 AM
Ok great. Thanks Julio
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