From CT3

By Ivan Pepelnjak

The BGP templates introduced in Cisco IOS releases 12.3T, 12.4, 12.2S and 12.2SBC allow you to group session-specific and routing-policy-specific BGP settings into templates with a hierarchical inheritance structure. The peer-session templates define all session-specific parameters (for example, update-source, ebgp-multihop, password, remote-as or local-as), while the peer-policy templates define parameters that influence routing policies, route filters, community propagation and generation of BGP updates (for example, route-map, filter-list, send-community and route-reflector-client).

The Cisco IOS documentation does not tell you how to apply BGP templates to multiple address families:

• The peer-session template is applied to the global neighbor definition.
• The peer-policy template needs to be applied to a neighbor for each address family in which the neighbor is activated.

For example, to configure two PE-routers (using both IPv4 and VPNv4 address families) as route-reflector clients on a route reflector, use the following configuration:

router bgp 65000
 template peer-policy Internal
  route-reflector-client
  send-community both
 exit-peer-policy
 !
 template peer-session Internal
  remote-as 65000
  update-source Loopback0
 exit-peer-session
 !
 bgp log-neighbor-changes
 neighbor 10.0.1.1 inherit peer-session Internal
 neighbor 10.0.1.1 description PE-A
 neighbor 10.0.1.2 inherit peer-session Internal
 neighbor 10.0.1.2 description PE-B
 !
 address-family ipv4
  no synchronization
  neighbor 10.0.1.1 activate
  neighbor 10.0.1.1 inherit peer-policy Internal
  neighbor 10.0.1.2 activate
  neighbor 10.0.1.2 inherit peer-policy Internal
  no auto-summary
 exit-address-family
 !
 address-family vpnv4
  neighbor 10.0.1.1 activate
  neighbor 10.0.1.1 send-community extended
  neighbor 10.0.1.1 inherit peer-policy Internal
  neighbor 10.0.1.2 activate
  neighbor 10.0.1.2 send-community extended
  neighbor 10.0.1.2 inherit peer-policy Internal
 exit-address-family