04-13-2012 02:42 AM
Hello Forum
As a beginner in mpls i am confused about the differnt routing processes.
In a lab we have 4 Backbone (MPLS speaking) 6509.
- Basic routing process is ospf where all the links between this boxes are in.
Configuration 1 6509 see below.
=>>> Where is the connector from the basic routing to the mp-bgp ? no redistribution ist configured. ist that somwhrer "implicit" ?
(Lab is working, but no one understand it )
....
!
ip vrf VPN_A
rd 65000:1
route-target export 65000:100
route-target import 65000:100
!
ip vrf VPN_B2
rd 65000:22
route-target export 65000:22
!
!
interface Loopback0
ip address 10.10.2.2 255.255.255.255
!
!
router ospf 100 vrf VPN_A
log-adjacency-changes
redistribute bgp 65000 subnets
network 10.0.27.1 0.0.0.0 area 0
network 10.0.28.1 0.0.0.0 area 0
!
!
ip vrf VPN_A
rd 65000:1
route-target export 65000:100
route-target import 65000:100
!
ip vrf VPN_B2
rd 65000:22
route-target export 65000:22
!
.....
mpls label protocol ldp
....
!
interface Loopback0
ip address 10.10.2.2 255.255.255.255
!
.....
!
router ospf 100 vrf VPN_A
log-adjacency-changes
redistribute bgp 65000 subnets
network 10.0.27.1 0.0.0.0 area 0
network 10.0.28.1 0.0.0.0 area 0
!
.....
!
router ospf 1
router-id 10.10.2.2
log-adjacency-changes
network 10.0.12.2 0.0.0.0 area 0
network 10.0.24.1 0.0.0.0 area 0
network 10.10.2.2 0.0.0.0 area 0
!
!
router bgp 65000
no bgp default ipv4-unicast
no bgp default route-target filter
bgp log-neighbor-changes
neighbor 10.10.1.1 remote-as 65000
neighbor 10.10.1.1 update-source Loopback0
neighbor 10.10.3.3 remote-as 65000
neighbor 10.10.3.3 update-source Loopback0
neighbor 10.10.4.4 remote-as 65000
neighbor 10.10.4.4 update-source Loopback0
neighbor 10.10.5.5 remote-as 65000
neighbor 10.10.5.5 update-source Loopback0
neighbor 10.10.6.6 remote-as 65000
neighbor 10.10.6.6 update-source Loopback0
!
address-family vpnv4
neighbor 10.10.1.1 activate
neighbor 10.10.1.1 send-community extended
neighbor 10.10.3.3 activate
neighbor 10.10.3.3 send-community extended
neighbor 10.10.4.4 activate
neighbor 10.10.4.4 send-community extended
neighbor 10.10.4.4 route-reflector-client
neighbor 10.10.5.5 activate
neighbor 10.10.5.5 send-community extended
neighbor 10.10.6.6 activate
neighbor 10.10.6.6 send-community extended
neighbor 10.10.6.6 route-reflector-client
exit-address-family
!
address-family ipv4 vrf VPN_SER1
redistribute ospf 50 vrf VPN_SER1
no synchronization
exit-address-family
!
address-family ipv4 vrf VPN_B2
redistribute connected
no synchronization
exit-address-family
!
address-family ipv4 vrf VPN_A
redistribute connected
redistribute ospf 100 vrf VPN_A
no synchronization
exit-address-family
!
!
router ospf 1
router-id 10.10.2.2
log-adjacency-changes
network 10.0.12.2 0.0.0.0 area 0
network 10.0.24.1 0.0.0.0 area 0
network 10.10.2.2 0.0.0.0 area 0
!
- BGP with adress families for the vrf's
!
router bgp 65000
no bgp default ipv4-unicast
no bgp default route-target filter
bgp log-neighbor-changes
neighbor 10.10.1.1 remote-as 65000
neighbor 10.10.1.1 update-source Loopback0
neighbor 10.10.3.3 remote-as 65000
neighbor 10.10.3.3 update-source Loopback0
neighbor 10.10.4.4 remote-as 65000
neighbor 10.10.4.4 update-source Loopback0
neighbor 10.10.5.5 remote-as 65000
neighbor 10.10.5.5 update-source Loopback0
neighbor 10.10.6.6 remote-as 65000
neighbor 10.10.6.6 update-source Loopback0
!
address-family vpnv4
neighbor 10.10.1.1 activate
neighbor 10.10.1.1 send-community extended
neighbor 10.10.3.3 activate
neighbor 10.10.3.3 send-community extended
neighbor 10.10.4.4 activate
neighbor 10.10.4.4 send-community extended
neighbor 10.10.4.4 route-reflector-client
neighbor 10.10.5.5 activate
neighbor 10.10.5.5 send-community extended
neighbor 10.10.6.6 activate
neighbor 10.10.6.6 send-community extended
neighbor 10.10.6.6 route-reflector-client
exit-address-family
!
address-family ipv4 vrf VPN_SER1
redistribute ospf 50 vrf VPN_SER1
no synchronization
exit-address-family
!
address-family ipv4 vrf VPN_B2
redistribute connected
no synchronization
exit-address-family
!
address-family ipv4 vrf VPN_A
redistribute connected
redistribute ospf 100 vrf VPN_A
no synchronization
exit-address-family
!
Thanks for help !
Martin
Solved! Go to Solution.
04-16-2012 05:01 AM
martin,
In order for BGP to form peering it needs to know the neighbor ip addresses right? so you achieve that layer 3 connectivity via some IGP when you have a couple of routers. Of course if they are directly connected then its not necessary to run IGP( depends on how u peer).
BGP is needed for MPLS VPN's between the PE's as its the routing protocol to carry the VPNv4 routes which is an address family which is not your normal ipv4.
for the PE-CE, its up to you to choose whichever routing protocol you want RIP,ospf, BGP etc
Hope this helps
Kishore
04-13-2012 02:46 AM
Hi Martin,
this is the MP-BGP snippet:
address-family vpnv4
neighbor 10.10.1.1 activate
neighbor 10.10.1.1 send-community extended
neighbor 10.10.3.3 activate
neighbor 10.10.3.3 send-community extended
neighbor 10.10.4.4 activate
neighbor 10.10.4.4 send-community extended
neighbor 10.10.4.4 route-reflector-client
neighbor 10.10.5.5 activate
neighbor 10.10.5.5 send-community extended
neighbor 10.10.6.6 activate
neighbor 10.10.6.6 send-community extended
neighbor 10.10.6.6 route-reflector-client
exit-address-family
try to check 'sh ip bgp neighbor' - you'll see the address-families negotiated.
HTH,
Ivan.
04-13-2012 03:08 AM
Hi Ivan
This will be the output:
bl1s101#sh ip bgp neighbors
bl1s101#
Did I understand you correct ?
Regards, Martin
04-13-2012 03:13 AM
Hi Martin,
sorry my bad, you don't have IPv4 AF negotiated, you better look at:
sh ip bgp vpnv4 all neighbors
Ivan.
04-13-2012 04:29 AM
Thanks again,
here my output.
bl1s101#sh ip bgp vpnv4 all neighbors
BGP neighbor is 10.10.1.1, remote AS 65000, internal link
BGP version 4, remote router ID 0.0.0.0
BGP state = Active
Last read 2w6d, last write 2w6d, hold time is 180, keepalive interval is 60 seconds
Message statistics:
InQ depth is 0
OutQ depth is 0
Sent Rcvd
Opens: 0 0
Notifications: 0 0
Updates: 0 0
Keepalives: 0 0
Route Refresh: 0 0
Total: 0 0
Default minimum time between advertisement runs is 0 seconds
For address family: VPNv4 Unicast
BGP table version 88, neighbor version 0/0
Output queue size : 0
Index 2, Offset 0, Mask 0x4
2 update-group member
Sent Rcvd
Prefix activity: ---- ----
Prefixes Current: 31 0
Prefixes Total: 0 0
Implicit Withdraw: 0 0
Explicit Withdraw: 0 0
Used as bestpath: n/a 0
Used as multipath: n/a 0
Outbound Inbound
Local Policy Denied Prefixes: -------- -------
Total: 0 0
Number of NLRIs in the update sent: max 0, min 0
Address tracking is enabled, the RIB does have a route to 10.10.1.1
Connections established 0; dropped 0
Last reset never
Transport(tcp) path-mtu-discovery is enabled
No active TCP connection
........
Sorry about my bad understanding but I can still not make the relationship between basic IGP Routing . OSPF 1 and the MPLS, MP-BGP.
Martin
04-13-2012 09:00 PM
Hi Martin,
For MPLS VPN's there are 3 things you need.
1. IGP- This is used between the PE-P-PE routers for full connectivity so that you can run bgp later on
2. BGP- for MP-BGP tranport safi
3. PE-CE routing protocol- could be ospf bgp, rip,eigrp etc
in your case ospf 1 is used as the tranport IGP which i mentioned in point 1.
router osp 50, 60 and all are used as PE-CE routing protocol
Does this help ? Let me know if u need more info
Kishore
04-16-2012 02:26 AM
Hi Kishore
Thank you - yes that helps.
What I still not understand ist HOW the BGP will learn the connectivity from the IGP ?
Other than with PE-CE there is no Redistribution.
Or I am totally false and there is no need for BGP to knowing that ?
Martin
04-16-2012 05:01 AM
martin,
In order for BGP to form peering it needs to know the neighbor ip addresses right? so you achieve that layer 3 connectivity via some IGP when you have a couple of routers. Of course if they are directly connected then its not necessary to run IGP( depends on how u peer).
BGP is needed for MPLS VPN's between the PE's as its the routing protocol to carry the VPNv4 routes which is an address family which is not your normal ipv4.
for the PE-CE, its up to you to choose whichever routing protocol you want RIP,ospf, BGP etc
Hope this helps
Kishore
04-19-2012 07:11 AM
Thank you!
Martin
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