1. BGP Connector Attribute
IETF 64 Nov 2005

2. Tunneling applications in BGP
Various Tunneling applications exist or are being proposed in BGP
Some examples are :
The MDT SAFI used for Auto-discovery of MDTs for PIM LAN procedures in Multicast VPNs
The Tunnel SAFI for Tunnel discovery

3. MDT discovery in PIM-LAN procedures for MVPNs
The MDT SAFI carries
the Tunnel endpoint address in the NLRI of the form RD:Tunnel-address, MDT-group address
Needs an RPF check on the Tunnel-endpoint-address
The VPNv4 update carries
the VPNv4 NLRI of the form RD: IP-address
a BGP Connector attribute of the form Tunnel-address
The BGP Connector attribute for the VPNv4 NLRI links the NLRI carried by the MDT SAFI

4. Tunnel Endpoint discovery
The Tunnel SAFI carries
the Tunnel endpoint address in the NLRI of the form Tunnel-ID:Tunnel-address
a BGP Tunnel Encapsulation attribute which contains encapsulations and preferences.
The VPNv4 update carries
the VPNv4 NLRI of the form RD: IP-address
a BGP Connector attribute of the form Tunnel-ID:Tunnel-address
The BGP Connector attribute for the VPNv4 NLRI links the Tunnel SAFI NLRI

5. Tunnel Discovery PE-2 CE-2 CE-2 PE-1 CE-1 PE-3 CE-3 VPNv4 update
RD2:1.1.1
NHOP = PE1
Connector = TunID2:PE1
PE-2
VPNv4 update
RD1:
NHOP = PE1
Connector = TunID1:PE1
CE-2
Host =
CE-2
PE-1
CE-1
Host =
PE-3
VPNv4 update
RD1:1.1.1
NHOP = PE1
Connector = TunID2:PE1
VPNv4 update
RD1:
NHOP = PE1
Connector = TunID1:PE1
CE-3

6. Tunnel Discovery (contd.)
VPNv4 update
RD1:
NHOP = PE1
Connector = TunID1:PE1
VPNv4 update
RD1:
NHOP = ASBR-1
Connector = TunID1:PE1
PE-1
PE-2
ASBR-1
ASBR-2
VPNv4 update
RD1:
NHOP = ASBR-1
Connector = TunID1:PE1
CE-1
Host =
CE-3

7. Summary
The Connector attribute is used for carrying the address of a Tunnel endpoint or an originator in a given network.
Already has 3 applications.
Could have more.