Filter
Top Products
33-2
Cisco ASR 901 Series Aggregation Services Router Software Configuration Guide
OL-23826-09
Chapter 33 Labeled BGP Support
Overview of Labeled BGP Support
Prerequisites
Cisco IOS Release 15.2(2)SNG or a later release that supports Labeled BGP must be installed previously
on the Cisco ASR 901 Series Aggregation Services Router.
Restrictions
• The Cisco ASR 901 router supports only the client functionality of RFC 3107 and not its area border
router (ABR) functionality.
• The Cisco ASR 901 router does not support two label-pop (Label pop is the process of removing
label header).
• Four label push is not supported. Due to this limitation, Labeled BGP access (RFC 3107) with
Remote LFA-FRR/TE-FRR is not supported, if it exceeds three labels.
Overview of Labeled BGP Support
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
Cisco ASR 901 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 Cisco ASR 901 router to support a VRF over labeled BGP session with an
ABR.
How to Configure Labeled BGP Support
Note The TDM over Labeled BGP feature is supported effective with Cisco IOS Release 15.3(3)S. The
configuration and restrictions for this feature are the same as that of Labeled BGP Support.
To configure Labeled BGP Support feature on the Cisco ASR 901 router, perform the steps given below:
SUMMARY STEPS
1. enable
2. configure terminal
3. router bgp as-number
4. address family ipv4
5. neighbor peer-group-name send-community