Prerequisites for Labeled BGP Support
Starting Cisco IOS XE Release 3.6.0S or later that supports Labeled BGP must be installed previously on the Cisco ASR 903 Series Aggregation Services Router.
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This feature module describes how to add label mapping information to the Border Gateway Protocol (BGP) message that is used to distribute the route on the router.
Starting Cisco IOS XE Release 3.6.0S or later that supports Labeled BGP must be installed previously on the Cisco ASR 903 Series Aggregation Services Router.
The router supports only the client functionality of RFC 3107 and not its area border router (ABR) functionality.
The router does not support two label-pop (Label pop is the process of removing label header).
The Labeled BGP Support feature provides the option to use the BGP update message (that is used to distribute the route) to re-distribute Multiprotocol Label Switching (MPLS) label mapped to that route. The label mapping information is added (using send-label option of RFC 3107) to the same BGP message that is used to distribute the route. This process is useful in inter-domain routing, and the message that is used to distribute the route. This process is useful in inter-domain routing, and the router supports this functionality as well as the virtual private network (VPN) and virtual routing and forwarding (VRF) over Labeled BGP functionality.
VPN/VRF over RFC 3107
The VPN/VRF over Labeled BGP is a 3-label imposition process (VRF Label, BGP label, interior gateway protocols [IGP] label). The innermost label is VRF, followed by BGP (for RFC 3107), and IGP. This functionality allows the router to support a VRF over labeled BGP session with an ABR.
Command or Action | Purpose | |
---|---|---|
Step 1 |
enable Example:
|
Enables privileged EXEC mode.
|
Step 2 |
configure terminal Example:
|
Enters global configuration mode. |
Step 3 |
router bgp as-number Example:
|
Enters router configuration mode.
|
Step 4 |
address family ipv4 Example:
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Configures the address family as IPv4 using standard IPv4 address prefixes. |
Step 5 |
neighbor peer-group-name send-community Example:
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Specifies that the communities attribute be sent to the neighbor at this IP address.
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Step 6 |
neighbor peer-group-name next-hop-self Example:
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Configures the router as the next hop for a BGP-speaking neighbor or peer group. |
Step 7 |
neighbor peer-group-name activate Example:
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Enables the exchange of information with a neighboring BGP router. |
The following is a sample configuration of the Labeled BGP Support feature.
!
router bgp 1000
bgp router-id 100.111.13.23
neighbor pan peer-group
neighbor pan remote-as 1000
neighbor pan update-source Loopback0
neighbor 100.111.14.3 peer-group pan
!
address-family ipv4
neighbor pan send-community
neighbor pan next-hop-self
neighbor pan send-label
!The send-label option is used to associate a BGP label to the prefix.
neighbor 100.111.14.3 activate
exit-address-family
!
address-family vpnv4
neighbor pan send-community extended
neighbor 100.111.14.3 activate
exit-address-family
!
address-family ipv4 vrf LTE12
redistribute connected
exit-address-family
!
To verify the Labeled BGP Support, use the show commands given below:
Router# show bgp ipv4 unicast labels
Network Next Hop In label/Out label
1.0.0.0 0.0.0.0 imp-null/nolabel
10.13.22.2/31 0.0.0.0 imp-null/nolabel
10.13.23.0/31 0.0.0.0 imp-null/nolabel
10.70.1.0/30 0.0.0.0 imp-null/nolabel
100.100.10.1/32 100.111.14.4 nolabel/558
100.111.14.3 nolabel/560
100.100.13.23/32 0.0.0.0 imp-null/nolabel
100.101.13.23/32 0.0.0.0 imp-null/nolabel
100.111.13.23/32 0.0.0.0 imp-null/nolabel
100.111.13.26/32 100.111.14.3 nolabel/534
100.111.14.4 nolabel/68
100.111.15.1/32 100.111.14.3 nolabel/25
Router# show ip bgp labels
Network Next Hop In label/Out label
1.0.0.0 0.0.0.0 imp-null/nolabel
10.13.22.2/31 0.0.0.0 imp-null/nolabel
10.13.23.0/31 0.0.0.0 imp-null/nolabel
10.70.1.0/30 0.0.0.0 imp-null/nolabel
100.100.10.1/32 100.111.14.4 nolabel/563
100.111.14.3 nolabel/556
100.100.13.23/32 0.0.0.0 imp-null/nolabel
100.101.13.23/32 0.0.0.0 imp-null/nolabel
100.111.13.23/32 0.0.0.0 imp-null/nolabel
100.111.13.26/32 100.111.14.4 nolabel/561
100.111.14.3 nolabel/559
100.111.15.1/32 100.111.14.4 nolabel/59
100.111.14.3 nolabel/57
100.111.15.2/32 100.111.14.4 nolabel/62
100.111.14.3 nolabel/52
100.112.1.1/32 100.111.14.4 nolabel/nolabel
100.111.14.3 nolabel/nolabel
100.112.1.2/32 100.111.14.4 nolabel/nolabel
100.111.14.3 nolabel/nolabel
100.112.1.3/32 100.111.14.4 nolabel/nolabel
100.111.14.3 nolabel/nolabel
Router# show ip bgp vpnv4 all label
Network Next Hop In label/Out label
Route Distinguisher: 236:236
154.154.236.4/30 100.154.1.1 nolabel/14002
100.154.1.1 nolabel/14002
154.154.236.8/30 100.154.1.1 nolabel/14002
100.154.1.1 nolabel/14002
154.154.236.12/30
100.154.1.1 nolabel/14002
100.154.1.1 nolabel/14002
154.154.236.16/30
100.154.1.1 nolabel/14002
100.154.1.1 nolabel/14002
154.154.236.20/30
100.154.1.1 nolabel/14002
100.154.1.1 nolabel/14002
154.154.236.24/30
100.154.1.1 nolabel/14002
100.154.1.1 nolabel/14002
Router# show ip vrf interface
Interface IP-Address VRF Protocol
Vl100 113.23.12.1 LTE12
Router# show ip bgp vpnv4 vrf LTE12 label
Network Next Hop In label/Out label
Route Distinguisher: 6666:6666 (LTE12)
113.22.12.0/24 100.111.13.22 nolabel/51
100.111.13.22 nolabel/51
113.23.12.0/24 0.0.0.0 50/nolabel(LTE12)
113.24.12.0/24 100.111.13.24 nolabel/32
100.111.13.24 nolabel/32
115.1.12.0/24 100.111.15.1 nolabel/16024
100.111.15.1 nolabel/16024
154.154.236.4/30 100.154.1.1 nolabel/14002
154.154.236.8/30 100.154.1.1 nolabel/14002
154.154.236.12/30
100.154.1.1 nolabel/14002
154.154.236.16/30
100.154.1.1 nolabel/14002
154.154.236.20/30
100.154.1.1 nolabel/14002
154.154.236.24/30
100.154.1.1 nolabel/14002
To verify three Label Support, use the show ip cef vrf command as shown in the following example.
Router# show ip cef vrf LTE12 113.22.12.0 internal
113.22.12.0/24, epoch 0, flags rib defined all labels, RIB[B], refcount 5, per-destination sharing
sources: RIB
feature space:
IPRM: 0x00018000
LFD: 113.22.12.0/24 0 local labels
contains path extension list
ifnums: (none)
path 13E8A064, path list 13F49DC8, share 1/1, type recursive, for IPv4, flags must-be-labelled, recursive-via-host
MPLS short path extensions: MOI flags = 0x0 label 51
recursive via 100.111.13.22[IPv4:Default] label 51, fib 141253D8, 1 terminal fib, v4:Default:100.111.13.22/32
path 12520C8C, path list 13F49C38, share 1/1, type attached nexthop, for IPv4
MPLS short path extensions: MOI flags = 0x0 label 17
nexthop 100.111.14.4 Vlan10 label 17, adjacency IP adj out of Vlan10, addr 10.13.23.1 13734C80
output chain: label 22 label 51 label 17 TAG adj out of Vlan10, addr 10.13.23.1 143EDCA0
!You can see three labels in the output chain; of which 22 is VRF label, 51 is BGP label !and 17 is LDP label
Related Topic | Document Title |
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Cisco IOS XE Command Reference | Cisco IOS IP Routing: BGP Command Reference |
Standard/RFC | Title |
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RFC-3107 |
Carrying Label Information in BGP-4 |
MIB | MIBs Link |
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NA |
To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL: |
Description | Link |
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